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5050 lines
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HTML
<HTML>
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<!-- Created on January, 23 2003 by texi2html 1.64 -->
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<!--
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Written by: Lionel Cons <Lionel.Cons@cern.ch> (original author)
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Karl Berry <karl@freefriends.org>
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Olaf Bachmann <obachman@mathematik.uni-kl.de>
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and many others.
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Maintained by: Olaf Bachmann <obachman@mathematik.uni-kl.de>
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Send bugs and suggestions to <texi2html@mathematik.uni-kl.de>
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<HEAD>
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<TITLE>GDB Manual: </TITLE>
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<META NAME="description" CONTENT="GDB Manual: ">
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<META NAME="keywords" CONTENT="GDB Manual: ">
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<META NAME="resource-type" CONTENT="document">
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</HEAD>
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<BODY LANG="" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#800080" ALINK="#FF0000">
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<A NAME="SEC_Top"></A>
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<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
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<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
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</TR></TABLE>
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<H1>GDB Manual</H1><H1> Summary of GDB </H1>
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<!--docid::SEC1::-->
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<P>
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The purpose of a debugger such as GDB is to allow you to execute another
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program while examining what is going on inside it. We call the other
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program "your program" or "the program being debugged".
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</P><P>
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GDB can do four kinds of things (plus other things in support of these):
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</P><P>
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<OL>
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<LI>
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Start the program, specifying anything that might affect its behavior.
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<P>
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<LI>
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Make the program stop on specified conditions.
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<P>
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<LI>
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Examine what has happened, when the program has stopped, so that you
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can see bugs happen.
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<P>
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<LI>
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Change things in the program, so you can correct the effects of one bug
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and go on to learn about another without having to recompile first.
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</OL>
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<P>
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GDB can be used to debug programs written in C and C++. Pascal support
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is being implemented, and Fortran support will be added when a GNU
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Fortran compiler is written.
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</P><P>
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<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC2">GDB General Public License</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">The GDB General Public License gives you permission
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to redistribute GDB on certain terms; and also
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explains that there is no warranty.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC5">1. GDB Input Conventions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">GDB command syntax and input conventions.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC6">2. Specifying GDB's Files</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying files for GDB to operate on.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC9">3. Options and Arguments for GDB</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">GDB arguments and options.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC13">4. Compiling Your Program for Debugging</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Compiling your program so you can debug it.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC14">5. Running Your Program Under GDB</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Running your program under GDB.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC20">6. Stopping and Continuing</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Making your program stop. Why it may stop. What to do then.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC31">7. Examining the Stack</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Examining your program's stack.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC36">8. Examining Source Files</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Examining your program's source files.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC40">9. Examining Data</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Examining data in your program.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Examining the debugger's symbol table.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC52">11. Altering Execution</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Altering things in your program.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC57">12. Canned Sequences of Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Canned command sequences for repeated use.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC61">13. Using GDB under GNU Emacs</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Using GDB through GNU Emacs.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC62">14. Remote Kernel Debugging</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Remote kernel debugging across a serial line.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC64">Command Index</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Index of GDB commands.</TD></TR>
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<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC65">Concept Index</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Index of GDB concepts.</TD></TR>
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</TABLE></BLOCKQUOTE>
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<P>
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<HR SIZE=1>
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<A NAME="SEC1"></A>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
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</TR></TABLE>
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<A NAME="License"></A>
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<HR SIZE="6">
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<A NAME="SEC2"></A>
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<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
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<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC1"> < </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC3"> > </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> << </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC5"> >> </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
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</TR></TABLE>
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<H1> GDB General Public License </H1>
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<!--docid::SEC2::-->
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<center>
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(Clarified 11 Feb 1988)
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</center>
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<P>
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The license agreements of most software companies keep you at the mercy
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of those companies. By contrast, our general public license is intended to
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give everyone the right to share GDB. To make sure that you get the rights
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we want you to have, we need to make restrictions that forbid anyone to
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deny you these rights or to ask you to surrender the rights. Hence this
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license agreement.
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</P><P>
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Specifically, we want to make sure that you have the right to give away
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copies of GDB, that you receive source code or else can get it if you want
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it, that you can change GDB or use pieces of it in new free programs, and
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that you know you can do these things.
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</P><P>
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To make sure that everyone has such rights, we have to forbid you to
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deprive anyone else of these rights. For example, if you distribute copies
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of GDB, you must give the recipients all the rights that you have. You
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must make sure that they, too, receive or can get the source code. And you
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must tell them their rights.
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</P><P>
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Also, for our own protection, we must make certain that everyone finds
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out that there is no warranty for GDB. If GDB is modified by someone else
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and passed on, we want its recipients to know that what they have is not
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what we distributed, so that any problems introduced by others will not
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reflect on our reputation.
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</P><P>
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Therefore we (Richard Stallman and the Free Software Foundation,
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Inc.) make the following terms which say what you must do to be
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allowed to distribute or change GDB.
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</P><P>
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<HR SIZE="6">
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<A NAME="SEC3"></A>
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<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
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<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC2"> < </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC4"> > </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
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</TR></TABLE>
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<H2> Copying Policies </H2>
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<!--docid::SEC3::-->
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<P>
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<OL>
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<LI>
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You may copy and distribute verbatim copies of GDB source code as you
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receive it, in any medium, provided that you conspicuously and
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appropriately publish on each file a valid copyright notice "Copyright
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(C) 1988 Free Software Foundation, Inc." (or with whatever year
|
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is appropriate); keep intact the notices on all files that
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refer to this License Agreement and to the absence of any warranty; and
|
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give any other recipients of the GDB program a copy of this License
|
|
Agreement along with the program. You may charge a distribution fee
|
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for the physical act of transferring a copy.
|
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<P>
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<LI>
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You may modify your copy or copies of GDB source code or any portion
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of it, and copy and distribute such modifications under the terms of
|
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Paragraph 1 above, provided that you also do the following:
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<P>
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<UL>
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<LI>
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cause the modified files to carry prominent notices stating
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that you changed the files and the date of any change; and
|
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<P>
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<LI>
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cause the whole of any work that you distribute or publish, that
|
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in whole or in part contains or is a derivative of GDB or any
|
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part thereof, to be licensed at no charge to all third parties on
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terms identical to those contained in this License Agreement
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(except that you may choose to grant more extensive warranty
|
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protection to some or all third parties, at your option).
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<P>
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<LI>
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if the modified program serves as a debugger, cause it, when
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started running in the simplest and usual way, to print an
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announcement including a valid copyright notice "Copyright
|
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(C) 1988 Free Software Foundation, Inc." (or with the
|
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year that is appropriate), saying that there is no warranty (or
|
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else, saying that you provide a warranty) and that users may
|
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redistribute the program under these conditions, and telling the
|
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user how to view a copy of this License Agreement.
|
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<P>
|
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|
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<LI>
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You may charge a distribution fee for the physical act of
|
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transferring a copy, and you may at your option offer warranty
|
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protection in exchange for a fee.
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</UL>
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<P>
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Mere aggregation of another unrelated program with this program (or its
|
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derivative) on a volume of a storage or distribution medium does not bring
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the other program under the scope of these terms.
|
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</P><P>
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<LI>
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You may copy and distribute GDB (or a portion or derivative of it,
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under Paragraph 2) in object code or executable form under the terms
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of Paragraphs 1 and 2 above provided that you also do one of the
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following:
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<P>
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<UL>
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<LI>
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accompany it with the complete corresponding machine-readable
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source code, which must be distributed under the terms of
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Paragraphs 1 and 2 above; or,
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<P>
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<LI>
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accompany it with a written offer, valid for at least three
|
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years, to give any third party free (except for a nominal
|
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shipping charge) a complete machine-readable copy of the
|
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corresponding source code, to be distributed under the terms of
|
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Paragraphs 1 and 2 above; or,
|
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<P>
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<LI>
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accompany it with the information you received as to where the
|
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corresponding source code may be obtained. (This alternative is
|
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allowed only for noncommercial distribution and only if you
|
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received the program in object code or executable form alone.)
|
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</UL>
|
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<P>
|
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For an executable file, complete source code means all the source code
|
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for all modules it contains; but, as a special exception, it need not
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include source code for modules which are standard libraries that
|
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accompany the operating system on which the executable file runs.
|
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</P><P>
|
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<LI>
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You may not copy, sublicense, distribute or transfer GDB except as
|
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expressly provided under this License Agreement. Any attempt
|
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otherwise to copy, sublicense, distribute or transfer GDB is void and
|
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your rights to use GDB under this License agreement shall be
|
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automatically terminated. However, parties who have received computer
|
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software programs from you with this License Agreement will not have
|
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their licenses terminated so long as such parties remain in full
|
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compliance.
|
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<P>
|
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<LI>
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If you wish to incorporate parts of GDB into other free programs whose
|
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distribution conditions are different, write to the Free Software
|
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Foundation. We have not yet worked out a simple rule that can be
|
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stated here, but we will often permit this. We will be guided by the
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two goals of preserving the free status of all derivatives our free
|
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software and of promoting the sharing and reuse of software.
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</OL>
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<P>
|
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<HR SIZE="6">
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<A NAME="SEC4"></A>
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<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
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<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC3"> < </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC5"> > </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[ << ]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
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</TR></TABLE>
|
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<H2> NO WARRANTY </H2>
|
|
<!--docid::SEC4::-->
|
|
<P>
|
|
|
|
BECAUSE GDB IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY
|
|
NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW. EXCEPT
|
|
WHEN OTHERWISE STATED IN WRITING, THE FREE SOFTWARE FOUNDATION, INC,
|
|
RICHARD M. STALLMAN AND/OR OTHER PARTIES PROVIDE GDB "AS IS"
|
|
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
|
|
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
|
|
FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY
|
|
AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE GDB
|
|
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY
|
|
SERVICING, REPAIR OR CORRECTION.
|
|
</P><P>
|
|
|
|
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL FREE SOFTWARE
|
|
FOUNDATION, INC., RICHARD M. STALLMAN, AND/OR ANY OTHER PARTY WHO MAY
|
|
MODIFY AND REDISTRIBUTE GDB AS PERMITTED ABOVE, BE LIABLE TO YOU
|
|
FOR DAMAGES, INCLUDING ANY LOST PROFITS, LOST MONIES, OR OTHER
|
|
SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR
|
|
INABILITY TO USE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA
|
|
BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR A
|
|
FAILURE OF THE PROGRAM TO OPERATE WITH PROGRAMS NOT DISTRIBUTED BY
|
|
FREE SOFTWARE FOUNDATION, INC.) THE PROGRAM, EVEN IF YOU HAVE BEEN
|
|
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM BY ANY
|
|
OTHER PARTY.
|
|
</P><P>
|
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<A NAME="Input"></A>
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<HR SIZE="6">
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<A NAME="SEC5"></A>
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<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 1. GDB Input Conventions </H1>
|
|
<!--docid::SEC5::-->
|
|
<P>
|
|
|
|
GDB is invoked with the shell command <SAMP>`gdb'</SAMP>. Once started, it reads
|
|
commands from the terminal until you tell it to exit.
|
|
</P><P>
|
|
|
|
A GDB command is a single line of input. There is no limit on how long
|
|
it can be. It starts with a command name, which is followed by arguments
|
|
whose meaning depends on the command name. Some command names do not
|
|
allow arguments.
|
|
</P><P>
|
|
|
|
GDB command names may always be abbreviated if the abbreviation is
|
|
unambiguous. Sometimes even ambiguous abbreviations are allowed; for
|
|
example, <SAMP>`s'</SAMP> is specially defined as equivalent to <SAMP>`step'</SAMP>
|
|
even though there are other commands whose names start with <SAMP>`s'</SAMP>.
|
|
Possible command abbreviations are often stated in the documentation
|
|
of the individual commands.
|
|
</P><P>
|
|
|
|
A blank line as input to GDB means to repeat the previous command verbatim.
|
|
Certain commands do not allow themselves to be repeated this way; these are
|
|
commands for which unintentional repetition might cause trouble and which
|
|
you are unlikely to want to repeat. Certain others (<SAMP>`list'</SAMP> and
|
|
<SAMP>`x'</SAMP>) act differently when repeated because that is more useful.
|
|
</P><P>
|
|
|
|
A line of input starting with <SAMP>`#'</SAMP> is a comment; it does nothing.
|
|
This is useful mainly in command files (See section <A HREF="gdb.html#SEC59">12.2 Command Files</A>).
|
|
</P><P>
|
|
|
|
Occasionally it is useful to execute a shell command from within gdb.
|
|
This can be done with the <SAMP>`shell'</SAMP> command, or the shell escape
|
|
character <SAMP>`!'</SAMP>.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>shell <VAR>shell command string</VAR></CODE>
|
|
<DD><A NAME="IDX1"></A>
|
|
<DT><CODE>!<VAR>shell command string</VAR></CODE>
|
|
<DD><A NAME="IDX2"></A>
|
|
<A NAME="IDX3"></A>
|
|
Directs GDB to invoke an inferior shell to execute <SAMP>`shell command string'</SAMP>.
|
|
The environmental variable <SAMP>`SHELL'</SAMP> is used if it exists, otherwise gdb
|
|
uses <SAMP>`/bin/sh'</SAMP>.
|
|
</DL>
|
|
<P>
|
|
|
|
GDB <EM>prompts</EM> for commands with a string that is normally <SAMP>`(gdb)'</SAMP>.
|
|
When debugging GDB with GDB, it is useful to change the prompt in one of
|
|
the GDBs so that you can distinguish them. This can be done with the
|
|
<SAMP>`set prompt'</SAMP> command.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>set prompt <VAR>newprompt</VAR></CODE>
|
|
<DD><A NAME="IDX4"></A>
|
|
Directs GDB to use <VAR>newprompt</VAR> as its prompt string henceforth.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="IDX5"></A>
|
|
<A NAME="IDX6"></A>
|
|
To exit GDB, use the <SAMP>`quit'</SAMP> command (abbreviated <SAMP>`q'</SAMP>).
|
|
<KBD>Ctrl-c</KBD> will not exit from GDB, but rather will terminate the action
|
|
of any GDB command that is in progress and return to GDB command level.
|
|
It is safe to type <KBD>Ctrl-c</KBD> at any time because GDB does not allow
|
|
it to take effect until a time when it is safe.
|
|
</P><P>
|
|
|
|
<A NAME="Files"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC6"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC5"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC7"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC5"> << </A>]</TD>
|
|
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|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> >> </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 2. Specifying GDB's Files </H1>
|
|
<!--docid::SEC6::-->
|
|
<P>
|
|
|
|
<A NAME="IDX7"></A>
|
|
<A NAME="IDX8"></A>
|
|
<A NAME="IDX9"></A>
|
|
GDB needs to know the filename of the program to be debugged. To debug a
|
|
core dump of a previous run, GDB must be told the filename of the core
|
|
dump.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC7">2.1 Specifying Files with Arguments</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying files with arguments</TD></TR>
|
|
</TABLE>
|
|
(when you start GDB).
|
|
<br>
|
|
<TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying files with GDB commands.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="File Arguments"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC7"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC6"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC8"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC6"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC6"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 2.1 Specifying Files with Arguments </H2>
|
|
<!--docid::SEC7::-->
|
|
<P>
|
|
|
|
The usual way to specify the executable and core dump file names is with
|
|
two command arguments given when you start GDB. The first argument is used
|
|
as the file for execution and symbols, and the second argument (if any) is
|
|
used as the core dump file name. Thus,
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>gdb progm core
|
|
</pre></td></tr></table></P><P>
|
|
|
|
specifies <TT>`progm'</TT> as the executable program and <TT>`core'</TT> as a core
|
|
dump file to examine. (You do not need to have a core dump file if what
|
|
you plan to do is debug the program interactively.)
|
|
</P><P>
|
|
|
|
See section <A HREF="gdb.html#SEC9">3. Options and Arguments for GDB</A>, for full information on command options and arguments for
|
|
GDB.
|
|
</P><P>
|
|
|
|
<A NAME="File Commands"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC8"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC7"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC6"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC6"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 2.2 Specifying Files with Commands </H2>
|
|
<!--docid::SEC8::-->
|
|
<P>
|
|
|
|
Usually you specify the files for GDB to work with by giving arguments when
|
|
you invoke GDB. But occasionally it is necessary to change to a different
|
|
file during a GDB session. Or you may run GDB and forget to specify the
|
|
files you want to use. In these situations the GDB commands to specify new
|
|
files are useful.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>exec-file <VAR>filename</VAR></CODE>
|
|
<DD><A NAME="IDX10"></A>
|
|
Specify that the program to be run is found in <VAR>filename</VAR>. If you
|
|
do not specify a directory and the file is not found in GDB's working
|
|
directory, GDB will use the environment variable <SAMP>`PATH'</SAMP> as a list
|
|
of directories to search, just as the shell does when looking for a
|
|
program to run.
|
|
<P>
|
|
|
|
<DT><CODE>symbol-file <VAR>filename</VAR></CODE>
|
|
<DD><A NAME="IDX11"></A>
|
|
Read symbol table information from file <VAR>filename</VAR>. <SAMP>`PATH'</SAMP>
|
|
is searched when necessary. Most of the time you will use both the
|
|
<SAMP>`exec-file'</SAMP> and <SAMP>`symbol-file'</SAMP> commands on the same file.
|
|
<P>
|
|
|
|
<SAMP>`symbol-file'</SAMP> with no argument clears out GDB's symbol table.
|
|
</P><P>
|
|
|
|
<DT><CODE>core-file <VAR>filename</VAR></CODE>
|
|
<DD><A NAME="IDX12"></A>
|
|
Specify the whereabouts of a core dump file to be used as the
|
|
"contents of memory". Note that the core dump contains only the
|
|
writable parts of memory; the read-only parts must come from the
|
|
executable file.
|
|
<P>
|
|
|
|
<SAMP>`core-file'</SAMP> with no argument specifies that no core file is
|
|
to be used.
|
|
</P><P>
|
|
|
|
<DT><CODE>add-file <VAR>filename</VAR> <VAR>address</VAR></CODE>
|
|
<DD><A NAME="IDX13"></A>
|
|
The <SAMP>`add-file'</SAMP> command takes two arguments, a file name, and the
|
|
address at which that file has been (or should be) dynamically loaded.
|
|
GDB will then treat that file as though it had always been dynamically
|
|
linked, and provide the user with all the normal GDB features, including
|
|
symbolic debugging.
|
|
<P>
|
|
|
|
With the <SAMP>`add-file'</SAMP> command, it is possible to debug code which was
|
|
not present in the initial load image of the program under test.
|
|
Suppose you have a program which can, while running, dynamically link a
|
|
program fragment into its address space. One program which does this is
|
|
KCL, a free common lisp implementation. The fragment will be loaded
|
|
into the main program's address space at some address, and the main
|
|
program can then call functions within the fragment by calculating (or
|
|
otherwise obtaining) their addresses.
|
|
</P><P>
|
|
|
|
<DT><CODE>kill</CODE>
|
|
<DD><A NAME="IDX14"></A>
|
|
Cancel running the program under GDB. This could be used if you wish
|
|
to debug a core dump instead. GDB ignores any core dump file if it is
|
|
actually running the program, so the <SAMP>`kill'</SAMP> command is the only
|
|
sure way to go back to using the core dump file.
|
|
<P>
|
|
|
|
<DT><CODE>info files</CODE>
|
|
<DD><A NAME="IDX15"></A>
|
|
Print the names of the executable and core dump files currently in
|
|
use by GDB, and the file from which symbols were loaded.
|
|
</DL>
|
|
<P>
|
|
|
|
While all three file-specifying commands allow both absolute and relative
|
|
file names as arguments, GDB always converts the file name to an absolute
|
|
one and remembers it that way.
|
|
</P><P>
|
|
|
|
The <SAMP>`symbol-file'</SAMP> command causes GDB to forget the contents of its
|
|
convenience variables, the value history, and all breakpoints and
|
|
auto-display expressions. This is because they may contain pointers to the
|
|
internal data recording symbols and data types, which are part of the old
|
|
symbol table data being discarded inside GDB.
|
|
</P><P>
|
|
|
|
<A NAME="Options"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC9"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC8"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC10"> > </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC6"> << </A>]</TD>
|
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|
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC13"> >> </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 3. Options and Arguments for GDB </H1>
|
|
<!--docid::SEC9::-->
|
|
<P>
|
|
|
|
When you invoke GDB, you can pass commands telling it what files to
|
|
operate on and what other things to do.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC10">3.1 Mode Options</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Options controlling modes of operation.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC11">3.2 File-specifying Options</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Options to specify files (executable, coredump, commands)</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC12">3.3 Other Arguments</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Any other arguments without options
|
|
also specify files.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Mode Options"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC10"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC11"> > </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC13"> >> </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 3.1 Mode Options </H2>
|
|
<!--docid::SEC10::-->
|
|
<P>
|
|
|
|
<DL COMPACT>
|
|
<DT><SAMP>`-nx'</SAMP>
|
|
<DD>Do not execute commands from the init files <TT>`.gdbinit'</TT>.
|
|
Normally, the commands in these files are executed after all the
|
|
command options and arguments have been processed. See section <A HREF="gdb.html#SEC59">12.2 Command Files</A>.
|
|
<P>
|
|
|
|
<DT><SAMP>`-q'</SAMP>
|
|
<DD>"Quiet". Do not print the usual introductory messages.
|
|
<P>
|
|
|
|
<DT><SAMP>`-batch'</SAMP>
|
|
<DD>Run in batch mode. Exit with code 1 after processing all the command
|
|
files specified with <SAMP>`-x'</SAMP> (and <TT>`.gdbinit'</TT>, if not
|
|
inhibited). Exit also if, due to an error, GDB would otherwise
|
|
attempt to read a command from the terminal.
|
|
<P>
|
|
|
|
<DT><SAMP>`-fullname'</SAMP>
|
|
<DD>This option is used when Emacs runs GDB as a subprocess. It tells GDB
|
|
to output the full file name and line number in a standard,
|
|
recognizable fashion each time a stack frame is displayed (which
|
|
includes each time the program stops). This recognizable format looks
|
|
like two <SAMP>`\032'</SAMP> characters, followed by the filename, line number
|
|
and character position separated by colons, and a newline. The
|
|
Emacs-to-GDB interface program uses the two <SAMP>`\032'</SAMP> characters as
|
|
a signal to display the source code for the frame.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="File Options"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC11"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC10"> < </A>]</TD>
|
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|
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|
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|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 3.2 File-specifying Options </H2>
|
|
<!--docid::SEC11::-->
|
|
<P>
|
|
|
|
All the options and command line arguments given are processed
|
|
in sequential order. The order makes a difference when the
|
|
<SAMP>`-x'</SAMP> command is used.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><SAMP>`-s <VAR>file</VAR>'</SAMP>
|
|
<DD>Read symbol table from file <VAR>file</VAR>.
|
|
<P>
|
|
|
|
<DT><SAMP>`-e <VAR>file</VAR>'</SAMP>
|
|
<DD>Use file <VAR>file</VAR> as the executable file to execute when
|
|
appropriate, and for examining pure data in conjunction with a core
|
|
dump.
|
|
<P>
|
|
|
|
<DT><SAMP>`-se <VAR>file</VAR>'</SAMP>
|
|
<DD>Read symbol table from file <VAR>file</VAR> and use it as the executable
|
|
file.
|
|
<P>
|
|
|
|
<DT><SAMP>`-c <VAR>file</VAR>'</SAMP>
|
|
<DD>Use file <VAR>file</VAR> as a core dump to examine.
|
|
<P>
|
|
|
|
<DT><SAMP>`-x <VAR>file</VAR>'</SAMP>
|
|
<DD>Execute GDB commands from file <VAR>file</VAR>.
|
|
<P>
|
|
|
|
<DT><SAMP>`-d <VAR>directory</VAR>'</SAMP>
|
|
<DD>Add <VAR>directory</VAR> to the path to search for source files.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Other Arguments"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC12"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC11"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC13"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC13"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 3.3 Other Arguments </H2>
|
|
<!--docid::SEC12::-->
|
|
<P>
|
|
|
|
If there are arguments to GDB that are not options or associated with
|
|
options, the first one specifies the symbol table and executable file name
|
|
(as if it were preceded by <SAMP>`-se'</SAMP>) and the second one specifies a core
|
|
dump file name (as if it were preceded by <SAMP>`-c'</SAMP>).
|
|
</P><P>
|
|
|
|
<A NAME="Compilation"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC13"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC12"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC9"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 4. Compiling Your Program for Debugging </H1>
|
|
<!--docid::SEC13::-->
|
|
<P>
|
|
|
|
In order to debug a program effectively, you need to ask for debugging
|
|
information when you compile it. This information in the object file
|
|
describes the data type of each variable or function and the correspondence
|
|
between source line numbers and addresses in the executable code.
|
|
</P><P>
|
|
|
|
To request debugging information, specify the <SAMP>`-g'</SAMP> option when you run
|
|
the compiler.
|
|
</P><P>
|
|
|
|
The Unix C compiler is unable to handle the <SAMP>`-g'</SAMP> and <SAMP>`-O'</SAMP> options
|
|
together. This means that you cannot ask for optimization if you ask for
|
|
debugger information.
|
|
</P><P>
|
|
|
|
The GNU C compiler supports <SAMP>`-g'</SAMP> with or without <SAMP>`-O'</SAMP>, making it
|
|
possible to debug optimized code. We recommend that you <EM>always</EM> use
|
|
<SAMP>`-g'</SAMP> whenever you compile a program. You may think the program is
|
|
correct, but there's no sense in pushing your luck.
|
|
</P><P>
|
|
|
|
If you are using the GNU C compiler, the GNU assembler and the GNU linker,
|
|
you can choose between two formats of debugging information: the standard
|
|
Unix format, which is what you get with <SAMP>`-g'</SAMP>, and GDB's own format,
|
|
which you request by using <SAMP>`-gg'</SAMP> instead of <SAMP>`-g'</SAMP>. This stores
|
|
debugging information in the executable file in a format much like that
|
|
which is used inside GDB. This has these advantages and disadvantages:
|
|
</P><P>
|
|
|
|
<UL>
|
|
<LI>
|
|
GDB can read <SAMP>`-gg'</SAMP> format more than twice as fast as Unix
|
|
<SAMP>`-g'</SAMP> format.
|
|
<P>
|
|
|
|
<LI>
|
|
The <SAMP>`-gg'</SAMP> format uses much more disk space than Unix format.
|
|
<P>
|
|
|
|
<LI>
|
|
The Unix debuggers can understand only Unix format, so you cannot use
|
|
Unix source-level debuggers if you compile with <SAMP>`-gg'</SAMP>. (The
|
|
<CODE>adb</CODE> debugger works with either format; it does not use this
|
|
information in any case.)
|
|
</UL>
|
|
<P>
|
|
|
|
<A NAME="Running"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC14"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC13"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC15"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC13"> << </A>]</TD>
|
|
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|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 5. Running Your Program Under GDB </H1>
|
|
<!--docid::SEC14::-->
|
|
<P>
|
|
|
|
<A NAME="IDX16"></A>
|
|
<A NAME="IDX17"></A>
|
|
To start your program under GDB, use the <SAMP>`run'</SAMP> command. The program
|
|
must already have been specified using the <SAMP>`exec-file'</SAMP> command or with
|
|
an argument to GDB (see section <A HREF="gdb.html#SEC6">2. Specifying GDB's Files</A>); what <SAMP>`run'</SAMP> does is create an
|
|
inferior process, load the program into it, and set it in motion.
|
|
</P><P>
|
|
|
|
The execution of a program is affected by certain information it receives
|
|
from its superior. GDB provides ways to specify them, which you must do
|
|
<I>before</I> starting the program. (You can change them after starting the
|
|
program, but such changes do not affect the program unless you start it
|
|
over again.)
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT>The <I>arguments.</I>
|
|
<DD>You specify the arguments to give the program as the arguments of the
|
|
<SAMP>`run'</SAMP> command.
|
|
<P>
|
|
|
|
<DT>The <I>environment.</I>
|
|
<DD>The program normally inherits its environment from GDB, but you can
|
|
use the GDB commands <SAMP>`set environment'</SAMP> and
|
|
<SAMP>`unset environment'</SAMP> to change parts of the environment that will
|
|
be given to the program.<P>
|
|
|
|
<DT>The <I>working directory.</I>
|
|
<DD>The program inherits its working directory from GDB. You can set GDB's
|
|
working directory with the <SAMP>`cd'</SAMP> command in GDB.
|
|
</DL>
|
|
<P>
|
|
|
|
After the <SAMP>`run'</SAMP> command, the debugger does nothing but wait for your
|
|
program to stop. See section <A HREF="gdb.html#SEC20">6. Stopping and Continuing</A>.
|
|
</P><P>
|
|
|
|
Note that once your program has been started by the <SAMP>`run'</SAMP> command,
|
|
you may evaluate expressions that involve calls to functions in the
|
|
inferior. See section <A HREF="gdb.html#SEC41">9.1 Expressions</A>. If you wish to evaluate a function
|
|
simply for it's side affects, you may use the <SAMP>`set'</SAMP> command.
|
|
See section <A HREF="gdb.html#SEC53">11.1 Assignment to Variables</A>.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC15">5.1 Your Program's Arguments</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying the arguments for your program.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC16">5.2 Your Program's Environment</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying the environment for your program.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC17">5.3 Your Program's Working Directory</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying the working directory for giving
|
|
to your program when it is run.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC18">5.4 Your Program's Input and Output</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying the program's standard input and output.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC19">5.5 Debugging an Already-Running Process</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Debugging a process started outside GDB.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Arguments"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC15"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC16"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> >> </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 5.1 Your Program's Arguments </H2>
|
|
<!--docid::SEC15::-->
|
|
<P>
|
|
|
|
<A NAME="IDX18"></A>
|
|
You specify the arguments to give the program as the arguments of the
|
|
<SAMP>`run'</SAMP> command. They are passed to a shell, which expands wildcard
|
|
characters and performs redirection of I/O, and thence to the program.
|
|
</P><P>
|
|
|
|
<SAMP>`run'</SAMP> with no arguments uses the same arguments used by the previous
|
|
<SAMP>`run'</SAMP>.
|
|
</P><P>
|
|
|
|
<A NAME="IDX19"></A>
|
|
The command <SAMP>`set args'</SAMP> can be used to specify the arguments to be used
|
|
the next time the program is run. If <SAMP>`set args'</SAMP> has no arguments, it
|
|
means to use no arguments the next time the program is run. If you have
|
|
run your program with arguments and want to run it again with no arguments,
|
|
this is the only way to do so.
|
|
</P><P>
|
|
|
|
<A NAME="Environment"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC16"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC15"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC17"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 5.2 Your Program's Environment </H2>
|
|
<!--docid::SEC16::-->
|
|
<P>
|
|
|
|
<A NAME="IDX20"></A>
|
|
The <EM>environment</EM> consists of a set of <EM>environment variables</EM> and
|
|
their values. Environment variables conventionally record such things as
|
|
your user name, your home directory, your terminal type, and your search
|
|
path for programs to run. Usually you set up environment variables with
|
|
the shell and they are inherited by all the other programs you run. When
|
|
debugging, it can be useful to try running the program with different
|
|
environments without having to start the debugger over again.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>info environment <VAR>varname</VAR></CODE>
|
|
<DD><A NAME="IDX21"></A>
|
|
Print the value of environment variable <VAR>varname</VAR> to be given to
|
|
your program when it is started. This command can be abbreviated
|
|
<SAMP>`i env <VAR>varname</VAR>'</SAMP>.
|
|
<P>
|
|
|
|
<DT><CODE>info environment</CODE>
|
|
<DD>Print the names and values of all environment variables to be given to
|
|
your program when it is started. This command can be abbreviated
|
|
<SAMP>`i env'</SAMP>.
|
|
<P>
|
|
|
|
<DT><CODE>set environment <VAR>varname</VAR> <VAR>value</VAR></CODE>
|
|
<DD><DT><CODE>set environment <VAR>varname</VAR> = <VAR>value</VAR></CODE>
|
|
<DD><A NAME="IDX22"></A>
|
|
Sets environment variable <VAR>varname</VAR> to <VAR>value</VAR>, for your program
|
|
only, not for GDB itself. <VAR>value</VAR> may be any string; the values of
|
|
environment variables are just strings, and any interpretation is
|
|
supplied by your program itself. The <VAR>value</VAR> parameter is optional;
|
|
if it is eliminated, the variable is set to a null value. This command
|
|
can be abbreviated as short as <SAMP>`set e'</SAMP>.
|
|
<P>
|
|
|
|
<DT><CODE>delete environment <VAR>varname</VAR></CODE>
|
|
<DD><A NAME="IDX23"></A>
|
|
<DT><CODE>unset environment <VAR>varname</VAR></CODE>
|
|
<DD><A NAME="IDX24"></A>
|
|
Remove variable <VAR>varname</VAR> from the environment to be passed to
|
|
your program. This is different from <SAMP>`set env <VAR>varname</VAR> ='</SAMP>
|
|
because <SAMP>`delete environment'</SAMP> makes a variable not be defined at
|
|
all, which is distinguishable from an empty value. This command can
|
|
be abbreviated <SAMP>`d e'</SAMP>.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Working Directory"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC17"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC16"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC18"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 5.3 Your Program's Working Directory </H2>
|
|
<!--docid::SEC17::-->
|
|
<P>
|
|
|
|
<A NAME="IDX25"></A>
|
|
Each time you start your program with <SAMP>`run'</SAMP>, it inherits its working
|
|
directory from the current working directory of GDB. GDB's working
|
|
directory is initially whatever it inherited from its superior, but you can
|
|
specify the working directory for GDB with the <SAMP>`cd'</SAMP> command.
|
|
</P><P>
|
|
|
|
The GDB working directory also serves as a default for the commands
|
|
that specify files for GDB to operate on. See section <A HREF="gdb.html#SEC6">2. Specifying GDB's Files</A>.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>cd <VAR>directory</VAR></CODE>
|
|
<DD><A NAME="IDX26"></A>
|
|
Set GDB's working directory to <VAR>directory</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>pwd</CODE>
|
|
<DD><A NAME="IDX27"></A>
|
|
Print GDB's working directory.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Input/Output"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC18"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC17"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC19"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 5.4 Your Program's Input and Output </H2>
|
|
<!--docid::SEC18::-->
|
|
<P>
|
|
|
|
<A NAME="IDX28"></A>
|
|
<A NAME="IDX29"></A>
|
|
By default, the program you run under GDB does input and output to the same
|
|
terminal that GDB uses.
|
|
</P><P>
|
|
|
|
You can redirect the program's input and/or output using <SAMP>`sh'</SAMP>-style
|
|
redirection commands in the <SAMP>`run'</SAMP> command. For example,
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>run > outfile
|
|
</pre></td></tr></table></P><P>
|
|
|
|
starts the program, diverting its output to the file <TT>`outfile'</TT>.
|
|
</P><P>
|
|
|
|
<A NAME="IDX30"></A>
|
|
Another way to specify where the program should do input and output is with
|
|
the <SAMP>`tty'</SAMP> command. This command accepts a file name as argument, and
|
|
causes this file to be the default for future <SAMP>`run'</SAMP> commands. It also
|
|
resets the controlling terminal for future <SAMP>`run'</SAMP> commands. For
|
|
example,
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>tty /dev/ttyb
|
|
</pre></td></tr></table></P><P>
|
|
|
|
directs that processes started with subsequent <SAMP>`run'</SAMP> commands default
|
|
to do input and output on the terminal <TT>`/dev/ttyb'</TT> and sets the
|
|
controlling terminal to <TT>`/dev/ttyb'</TT>. An explicit redirection in
|
|
<SAMP>`run'</SAMP> overrides the <SAMP>`tty'</SAMP> command's effect on input/output
|
|
redirection.
|
|
</P><P>
|
|
|
|
When you use the <SAMP>`tty'</SAMP> command or redirect input in the <SAMP>`run'</SAMP>
|
|
command, the <EM>input for your program</EM> comes from the specified file,
|
|
but the input for GDB still comes from your terminal.
|
|
</P><P>
|
|
|
|
<A NAME="Attach"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC19"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC18"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 5.5 Debugging an Already-Running Process </H2>
|
|
<!--docid::SEC19::-->
|
|
<P>
|
|
|
|
Some operating systems (in particular, Sun) allow GDB to begin debugging an
|
|
already-running process that was started outside of GDB. To do this you
|
|
must use the <SAMP>`attach'</SAMP> command instead of the <SAMP>`run'</SAMP> command.
|
|
</P><P>
|
|
|
|
The <SAMP>`attach'</SAMP> command requires one argument, which is the process-id of
|
|
the process you want to debug. (The usual way to find out the process-id
|
|
of the process is with the <SAMP>`ps'</SAMP> utility.)
|
|
</P><P>
|
|
|
|
The first thing GDB does after arranging to debug the process is to stop
|
|
it. You can examine and modify an attached process with all the GDB
|
|
commands that ordinarily available when you start processes with
|
|
<SAMP>`run'</SAMP>. You can insert breakpoints; you can step and continue; you
|
|
can modify storage. If you would rather the process continue running,
|
|
use the <SAMP>`continue'</SAMP> command after attaching.
|
|
</P><P>
|
|
|
|
When you are finished debugging the attached process, you can use the
|
|
<SAMP>`detach'</SAMP> command to release it from GDB's control. Detaching
|
|
the process continues its execution. After the <SAMP>`detach'</SAMP> command,
|
|
that process and GDB become completely independent once more, and you
|
|
are ready to <SAMP>`attach'</SAMP> another process or start one with <SAMP>`run'</SAMP>.
|
|
</P><P>
|
|
|
|
If you exit GDB or use the <SAMP>`run'</SAMP> command while you have an attached
|
|
process, you kill that process. You will be asked for confirmation if you
|
|
try to do either of these things.
|
|
</P><P>
|
|
|
|
<A NAME="Stopping"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC20"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC19"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC14"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 6. Stopping and Continuing </H1>
|
|
<!--docid::SEC20::-->
|
|
<P>
|
|
|
|
When you run a program normally, it runs until exiting. The purpose
|
|
of using a debugger is so that you can stop it before that point;
|
|
or so that if the program runs into trouble you can find out why.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC21">6.1 Signals</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Fatal signals in your program just stop it;
|
|
then you can use GDB to see what is going on.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC22">6.2 Breakpoints</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Breakpoints let you stop your program when it
|
|
reaches a specified point in the code.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC29">6.3 Continuing</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Resuming execution until the next signal or breakpoint.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Stepping runs the program a short distance and
|
|
then stops it wherever it has come to.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Signals"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC21"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 6.1 Signals </H2>
|
|
<!--docid::SEC21::-->
|
|
<P>
|
|
|
|
A signal is an asynchronous event that can happen in a program. The
|
|
operating system defines the possible kinds of signals, and gives each kind
|
|
a name and a number. For example, <CODE>SIGINT</CODE> is the signal a program
|
|
gets when you type <KBD>Ctrl-c</KBD>; <CODE>SIGSEGV</CODE> is the signal a program
|
|
gets from referencing a place in memory far away from all the areas in use;
|
|
<CODE>SIGALRM</CODE> occurs when the alarm clock timer goes off (which happens
|
|
only if the program has requested an alarm).
|
|
</P><P>
|
|
|
|
Some signals, including <CODE>SIGALRM</CODE>, are a normal part of the
|
|
functioning of the program. Others, such as <CODE>SIGSEGV</CODE>, indicate
|
|
errors; these signals are <EM>fatal</EM> (kill the program immediately) if the
|
|
program has not specified in advance some other way to handle the signal.
|
|
<CODE>SIGINT</CODE> does not indicate an error in the program, but it is normally
|
|
fatal so it can carry out the purpose of <KBD>Ctrl-c</KBD>: to kill the program.
|
|
</P><P>
|
|
|
|
GDB has the ability to detect any occurrence of a signal in the program
|
|
running under GDB's control. You can tell GDB in advance what to do for
|
|
each kind of signal.
|
|
</P><P>
|
|
|
|
Normally, GDB is set up to ignore non-erroneous signals like <CODE>SIGALRM</CODE>
|
|
(so as not to interfere with their role in the functioning of the program)
|
|
but to stop the program immediately whenever an error signal happens.
|
|
You can change these settings with the <SAMP>`handle'</SAMP> command. You must
|
|
specify which signal you are talking about with its number.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>info signal</CODE>
|
|
<DD><A NAME="IDX31"></A>
|
|
Print a table of all the kinds of signals and how GDB has been told to
|
|
handle each one. You can use this to see the signal numbers of all
|
|
the defined types of signals.
|
|
<P>
|
|
|
|
<DT><CODE>handle <VAR>signalnum</VAR> <VAR>keywords</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX32"></A>
|
|
Change the way GDB handles signal <VAR>signalnum</VAR>. The <VAR>keywords</VAR>
|
|
say what change to make.
|
|
</DL>
|
|
<P>
|
|
|
|
To use the <SAMP>`handle'</SAMP> command you must know the code number of the
|
|
signal you are concerned with. To find the code number, type <SAMP>`info
|
|
signal'</SAMP> which prints a table of signal names and numbers.
|
|
</P><P>
|
|
|
|
The keywords allowed by the handle command can be abbreviated. Their full
|
|
names are
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>stop</CODE>
|
|
<DD>GDB should stop the program when this signal happens. This implies
|
|
the <SAMP>`print'</SAMP> keyword as well.
|
|
<P>
|
|
|
|
<DT><CODE>print</CODE>
|
|
<DD>GDB should print a message when this signal happens.
|
|
<P>
|
|
|
|
<DT><CODE>nostop</CODE>
|
|
<DD>GDB should not stop the program when this signal happens. It may
|
|
still print a message telling you that the signal has come in.
|
|
<P>
|
|
|
|
<DT><CODE>noprint</CODE>
|
|
<DD>GDB should not mention the occurrence of the signal at all. This
|
|
implies the <SAMP>`nostop'</SAMP> keyword as well.
|
|
<P>
|
|
|
|
<DT><CODE>pass</CODE>
|
|
<DD>GDB should allow the program to see this signal; the program will be
|
|
able to handle the signal, or may be terminated if the signal is fatal
|
|
and not handled.
|
|
<P>
|
|
|
|
<DT><CODE>nopass</CODE>
|
|
<DD>GDB should not allow the program to see this signal.
|
|
</DL>
|
|
<P>
|
|
|
|
When a signal has been set to stop the program, the program cannot see the
|
|
signal until you continue. It will see the signal then, if <SAMP>`pass'</SAMP> is
|
|
in effect for the signal in question <I>at that time</I>. In other words,
|
|
after GDB reports a signal, you can use the <SAMP>`handle'</SAMP> command with
|
|
<SAMP>`pass'</SAMP> or <SAMP>`nopass'</SAMP> to control whether that signal will be seen by
|
|
the program when you later continue it.
|
|
</P><P>
|
|
|
|
You can also use the <SAMP>`signal'</SAMP> command to prevent the program from
|
|
seeing a signal, or cause it to see a signal it normally would not see,
|
|
or to give it any signal at any time. See section <A HREF="gdb.html#SEC55">11.3 Giving the Program a Signal</A>.
|
|
</P><P>
|
|
|
|
<A NAME="Breakpoints"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC22"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC23"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 6.2 Breakpoints </H2>
|
|
<!--docid::SEC22::-->
|
|
<P>
|
|
|
|
<A NAME="IDX33"></A>
|
|
A <EM>breakpoint</EM> makes your program stop whenever a certain point in the
|
|
program is reached. You set breakpoints explicitly with GDB commands,
|
|
specifying the place where the program should stop by line number, function
|
|
name or exact address in the program. You can add various other conditions
|
|
to control whether the program will stop.
|
|
</P><P>
|
|
|
|
Each breakpoint is assigned a number when it is created; these numbers are
|
|
successive integers starting with 1. In many of the commands for controlling
|
|
various features of breakpoints you use the breakpoint number to say which
|
|
breakpoint you want to change. Each breakpoint may be <EM>enabled</EM> or
|
|
<EM>disabled</EM>; if disabled, it has no effect on the program until you
|
|
enable it again.
|
|
</P><P>
|
|
|
|
<A NAME="IDX34"></A>
|
|
<A NAME="IDX35"></A>
|
|
The command <SAMP>`info break'</SAMP> prints a list of all breakpoints set and not
|
|
cleared, showing their numbers, where in the program they are, and any
|
|
special features in use for them. Disabled breakpoints are included in the
|
|
list, but marked as disabled. <SAMP>`info break'</SAMP> with a breakpoint number
|
|
as argument lists only that breakpoint. The convenience variable <SAMP>`$_'</SAMP>
|
|
and the default examining-address for the <SAMP>`x'</SAMP> command are set to the
|
|
address of the last breakpoint listed (see section <A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A>).
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC23">6.2.1 Setting Breakpoints</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to establish breakpoints.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC24">6.2.2 Clearing Breakpoints</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to remove breakpoints no longer needed.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to disable breakpoints (turn them off temporarily).</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Making extra conditions on whether to stop.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC27">6.2.5 Commands Executed on Breaking</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Commands to be executed at a breakpoint.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC28">6.2.6 "Cannot Insert Breakpoints" Error</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">"Cannot insert breakpoints" error--why, what to do.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Set Breaks"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC23"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC24"> > </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 6.2.1 Setting Breakpoints </H3>
|
|
<!--docid::SEC23::-->
|
|
<P>
|
|
|
|
<A NAME="IDX36"></A>
|
|
Breakpoints are set with the <SAMP>`break'</SAMP> command (abbreviated <SAMP>`b'</SAMP>).
|
|
You have several ways to say where the breakpoint should go.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>break <VAR>function</VAR></CODE>
|
|
<DD>Set a breakpoint at entry to function <VAR>function</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>break <VAR>linenum</VAR></CODE>
|
|
<DD>Set a breakpoint at line <VAR>linenum</VAR> in the current source file.
|
|
That file is the last file whose source text was printed. This
|
|
breakpoint will stop the program just before it executes any of the
|
|
code on that line.
|
|
<P>
|
|
|
|
<DT><CODE>break <VAR>filename</VAR>:<VAR>linenum</VAR></CODE>
|
|
<DD>Set a breakpoint at line <VAR>linenum</VAR> in source file <VAR>filename</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>break <VAR>filename</VAR>:<VAR>function</VAR></CODE>
|
|
<DD>Set a breakpoint at entry to function <VAR>function</VAR> found in file
|
|
<VAR>filename</VAR>. Specifying a filename as well as a function name is
|
|
superfluous except when multiple files contain similarly named
|
|
functions.
|
|
<P>
|
|
|
|
<DT><CODE>break *<VAR>address</VAR></CODE>
|
|
<DD>Set a breakpoint at address <VAR>address</VAR>. You can use this to set
|
|
breakpoints in parts of the program which do not have debugging
|
|
information or source files.
|
|
<P>
|
|
|
|
<DT><CODE>break</CODE>
|
|
<DD>Set a breakpoint at the next instruction to be executed in the selected
|
|
stack frame (see section <A HREF="gdb.html#SEC31">7. Examining the Stack</A>). In any selected frame but the innermost,
|
|
this will cause the program to stop as soon as control returns to that
|
|
frame. This is equivalent to a <SAMP>`finish'</SAMP> command in the frame
|
|
inside the selected frame. If this is done in the innermost frame gdb
|
|
will stop the next time it reaches the current location; this may be
|
|
useful inside of loops. It does not stop at this breakpoint immediately
|
|
upon continuation of the program since no code would be executed if it
|
|
did.
|
|
<P>
|
|
|
|
<DT><CODE>break <small>...</small> if <VAR>cond</VAR></CODE>
|
|
<DD>Set a breakpoint with condition <VAR>cond</VAR>; evaluate the expression
|
|
<VAR>cond</VAR> each time the breakpoint is reached, and stop only if the
|
|
value is nonzero. <SAMP>`<small>...</small>'</SAMP> stands for one of the possible
|
|
arguments described above (or no argument) specifying where to break.
|
|
See section <A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A>, for more information on breakpoint conditions.
|
|
<P>
|
|
|
|
<DT><CODE>tbreak <VAR>args</VAR></CODE>
|
|
<DD><A NAME="IDX37"></A>
|
|
Set a breakpoint enabled only for one stop. <VAR>args</VAR> are the
|
|
same as in the <SAMP>`break'</SAMP> command, and the breakpoint is set in the same
|
|
way, but the breakpoint is automatically <EM>disabled</EM> the first time it
|
|
is hit.
|
|
</DL>
|
|
<P>
|
|
|
|
GDB allows you to set any number of breakpoints at the same place in the
|
|
program. There is nothing silly or meaningless about this. When the
|
|
breakpoints are conditional, this is even useful (see section <A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A>).
|
|
</P><P>
|
|
|
|
<A NAME="Clear Breaks"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC24"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC23"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC25"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 6.2.2 Clearing Breakpoints </H3>
|
|
<!--docid::SEC24::-->
|
|
<P>
|
|
|
|
<A NAME="IDX38"></A>
|
|
<A NAME="IDX39"></A>
|
|
It is often necessary to eliminate a breakpoint once it has done its job
|
|
and you no longer want the program to stop there. This is called
|
|
<EM>clearing</EM> or <SAMP>`deleting'</SAMP> the breakpoint. A breakpoint that
|
|
has been cleared no longer exists in any sense.
|
|
</P><P>
|
|
|
|
With the <SAMP>`clear'</SAMP> command you can clear breakpoints according to where
|
|
they are in the program. With the <SAMP>`delete'</SAMP> command you can clear
|
|
individual breakpoints by specifying their breakpoint numbers.
|
|
</P><P>
|
|
|
|
<B>It is not necessary to clear a breakpoint to proceed past it.</B> GDB
|
|
automatically ignores breakpoints in the first instruction to be executed
|
|
when you continue execution at the same address where the program stopped.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>clear</CODE>
|
|
<DD><A NAME="IDX40"></A>
|
|
Clear any breakpoints at the next instruction to be executed in the
|
|
selected stack frame (see section <A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A>). When the innermost frame
|
|
is selected, this is a good way to clear a breakpoint that the program
|
|
just stopped at.
|
|
<P>
|
|
|
|
<DT><CODE>clear <VAR>function</VAR></CODE>
|
|
<DD><DT><CODE>clear <VAR>filename</VAR>:<VAR>function</VAR></CODE>
|
|
<DD>Clear any breakpoints set at entry to the function <VAR>function</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>clear <VAR>linenum</VAR></CODE>
|
|
<DD><DT><CODE>clear <VAR>filename</VAR>:<VAR>linenum</VAR></CODE>
|
|
<DD>Clear any breakpoints set at or within the code of the specified line.
|
|
<P>
|
|
|
|
<DT><CODE>delete <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX41"></A>
|
|
Delete the breakpoints of the numbers specified as arguments.
|
|
A breakpoint deleted is forgotten completely.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Disabling"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC25"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC24"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC26"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 6.2.3 Disabling Breakpoints </H3>
|
|
<!--docid::SEC25::-->
|
|
<P>
|
|
|
|
<A NAME="IDX42"></A>
|
|
<A NAME="IDX43"></A>
|
|
Rather than clearing a breakpoint, you might prefer to <EM>disable</EM> it.
|
|
This makes the breakpoint inoperative as if it had been cleared, but
|
|
remembers the information on the breakpoint so that you can <EM>enable</EM>
|
|
it again later.
|
|
</P><P>
|
|
|
|
You disable and enable breakpoints with the <SAMP>`enable'</SAMP> and
|
|
<SAMP>`disable'</SAMP> commands, specifying one or more breakpoint numbers as
|
|
arguments. Use <SAMP>`info break'</SAMP> to print a list of breakpoints if you
|
|
don't know which breakpoint numbers to use.
|
|
</P><P>
|
|
|
|
A breakpoint can have any of four different states of enablement:
|
|
</P><P>
|
|
|
|
<UL>
|
|
<LI>
|
|
Enabled. The breakpoint will stop the program. A breakpoint made
|
|
with the <SAMP>`break'</SAMP> command starts out in this state.
|
|
<LI>
|
|
Disabled. The breakpoint has no effect on the program.
|
|
<LI>
|
|
Enabled once. The breakpoint will stop the program, but
|
|
when it does so it will become disabled. A breakpoint made
|
|
with the <SAMP>`tbreak'</SAMP> command starts out in this state.
|
|
<LI>
|
|
Enabled for deletion. The breakpoint will stop the program, but
|
|
immediately after it does so it will be deleted permanently.
|
|
</UL>
|
|
<P>
|
|
|
|
You change the state of enablement of a breakpoint with the following
|
|
commands:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>disable breakpoints <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX44"></A>
|
|
<DT><CODE>disable <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX45"></A>
|
|
Disable the specified breakpoints. A disabled breakpoint has no
|
|
effect but is not forgotten. All options such as ignore-counts,
|
|
conditions and commands are remembered in case the breakpoint is
|
|
enabled again later.
|
|
<P>
|
|
|
|
<DT><CODE>enable breakpoints <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX46"></A>
|
|
<DT><CODE>enable <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX47"></A>
|
|
Enable the specified breakpoints. They become effective once again in
|
|
stopping the program, until you specify otherwise.
|
|
<P>
|
|
|
|
<DT><CODE>enable breakpoints once <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD><DT><CODE>enable once <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD>Enable the specified breakpoints temporarily. Each will be disabled
|
|
again the next time it stops the program (unless you have used one of
|
|
these commands to specify a different state before that time comes).
|
|
<P>
|
|
|
|
<DT><CODE>enable breakpoints delete <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD><DT><CODE>enable delete <VAR>bnums</VAR><small>...</small></CODE>
|
|
<DD>Enable the specified breakpoints to work once and then die. Each of
|
|
the breakpoints will be deleted the next time it stops the program
|
|
(unless you have used one of these commands to specify a different
|
|
state before that time comes).
|
|
</DL>
|
|
<P>
|
|
|
|
Aside from the automatic disablement or deletion of a breakpoint when it
|
|
stops the program, which happens only in certain states, the state of
|
|
enablement of a breakpoint changes only when one of the commands above
|
|
is used.
|
|
</P><P>
|
|
|
|
<A NAME="Conditions"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC26"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC25"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC27"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 6.2.4 Break Conditions </H3>
|
|
<!--docid::SEC26::-->
|
|
<P>
|
|
|
|
<A NAME="IDX48"></A>
|
|
The simplest sort of breakpoint breaks every time the program reaches a
|
|
specified place. You can also specify a <EM>condition</EM> for a breakpoint.
|
|
A condition is just a boolean expression in your programming language
|
|
(See section <A HREF="gdb.html#SEC41">9.1 Expressions</A>). A breakpoint with a condition evaluates the
|
|
expression each time the program reaches it, and the program stops
|
|
only if the condition is true.
|
|
</P><P>
|
|
|
|
Break conditions may have side effects, and may even call functions in your
|
|
program. These may sound like strange things to do, but their effects are
|
|
completely predictable unless there is another enabled breakpoint at the
|
|
same address. (In that case, GDB might see the other breakpoint first and
|
|
stop the program without checking the condition of this one.) Note that
|
|
breakpoint commands are usually more convenient and flexible for the
|
|
purpose of performing side effects when a breakpoint is reached
|
|
(see section <A HREF="gdb.html#SEC27">6.2.5 Commands Executed on Breaking</A>).
|
|
</P><P>
|
|
|
|
Break conditions can be specified when a breakpoint is set, by using
|
|
<SAMP>`if'</SAMP> in the arguments to the <SAMP>`break'</SAMP> command. See section <A HREF="gdb.html#SEC23">6.2.1 Setting Breakpoints</A>.
|
|
They can also be changed at any time with the <SAMP>`condition'</SAMP> command:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>condition <VAR>bnum</VAR> <VAR>expression</VAR></CODE>
|
|
<DD><A NAME="IDX49"></A>
|
|
Specify <VAR>expression</VAR> as the break condition for breakpoint number
|
|
<VAR>bnum</VAR>. From now on, this breakpoint will stop the program only if
|
|
the value of <VAR>expression</VAR> is true (nonzero, in C). <VAR>expression</VAR>
|
|
is not evaluated at the time the <SAMP>`condition'</SAMP> command is given.
|
|
See section <A HREF="gdb.html#SEC41">9.1 Expressions</A>.
|
|
<P>
|
|
|
|
<DT><CODE>condition <VAR>bnum</VAR></CODE>
|
|
<DD>Remove the condition from breakpoint number <VAR>bnum</VAR>. It becomes
|
|
an ordinary unconditional breakpoint.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="IDX50"></A>
|
|
A special feature is provided for one kind of condition: to prevent the
|
|
breakpoint from doing anything until it has been reached a certain number
|
|
of times. This is done with the <EM>ignore count</EM> of the breakpoint.
|
|
When the program reaches a breakpoint whose ignore count is positive, then
|
|
instead of stopping, it just decrements the ignore count by one and
|
|
continues.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>ignore <VAR>bnum</VAR> <VAR>count</VAR></CODE>
|
|
<DD><A NAME="IDX51"></A>
|
|
Set the ignore count of breakpoint number <VAR>bnum</VAR> to <VAR>count</VAR>.
|
|
The next <VAR>count</VAR> times the breakpoint is reached, it will not stop.
|
|
<P>
|
|
|
|
To make the breakpoint stop the next time it is reached, specify
|
|
a count of zero.
|
|
</P><P>
|
|
|
|
<DT><CODE>cont <VAR>count</VAR></CODE>
|
|
<DD>Continue execution of the program, setting the ignore count of the
|
|
breakpoint that the program stopped at to <VAR>count</VAR> minus one.
|
|
Continuing through the breakpoint does not itself count as one of
|
|
<VAR>count</VAR>. Thus, the program will not stop at this breakpoint until the
|
|
<VAR>count</VAR>'th time it is hit.
|
|
<P>
|
|
|
|
This command is allowed only when the program stopped due to a
|
|
breakpoint. At other times, the argument to <SAMP>`cont'</SAMP> is ignored.
|
|
</DL>
|
|
<P>
|
|
|
|
If a breakpoint has a positive ignore count and a condition, the condition
|
|
is not checked. Once the ignore count reaches zero, the condition will
|
|
start to be checked.
|
|
</P><P>
|
|
|
|
Note that you could achieve the effect of the ignore count with a condition
|
|
such as <SAMP>`$foo-- <= 0'</SAMP> using a debugger convenience variable that is
|
|
decremented each time. That is why the ignore count is considered a
|
|
special case of a condition. See section <A HREF="gdb.html#SEC48">9.7 Convenience Variables</A>.
|
|
</P><P>
|
|
|
|
<A NAME="Break Commands"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC27"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC26"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC28"> > </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 6.2.5 Commands Executed on Breaking </H3>
|
|
<!--docid::SEC27::-->
|
|
<P>
|
|
|
|
<A NAME="IDX52"></A>
|
|
You can give any breakpoint a series of commands to execute when the
|
|
program stops due to that breakpoint. For example, you might want to
|
|
print the values of certain expressions, or enable other breakpoints.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>commands <VAR>bnum</VAR></CODE>
|
|
<DD>Specify commands for breakpoint number <VAR>bnum</VAR>. The commands
|
|
themselves appear on the following lines. Type a line containing just
|
|
<SAMP>`end'</SAMP> to terminate the commands.
|
|
<P>
|
|
|
|
To remove all commands from a breakpoint, use the command
|
|
<SAMP>`commands'</SAMP> and follow it immediately by <SAMP>`end'</SAMP>; that is, give
|
|
no commands.
|
|
</P><P>
|
|
|
|
With no arguments, <SAMP>`commands'</SAMP> refers to the last breakpoint set.
|
|
</DL>
|
|
<P>
|
|
|
|
It is possible for breakpoint commands to start the program up again.
|
|
Simply use the <SAMP>`cont'</SAMP> command, or <SAMP>`step'</SAMP>, or any other command
|
|
to resume execution. However, any remaining breakpoint commands are
|
|
ignored. When the program stops again, GDB will act according to why
|
|
that stop took place.
|
|
</P><P>
|
|
|
|
<A NAME="IDX53"></A>
|
|
If the first command specified is <SAMP>`silent'</SAMP>, the usual message about
|
|
stopping at a breakpoint is not printed. This may be desirable for
|
|
breakpoints that are to print a specific message and then continue.
|
|
If the remaining commands too print nothing, you will see no sign that
|
|
the breakpoint was reached at all. <SAMP>`silent'</SAMP> is not really a command;
|
|
it is meaningful only at the beginning of the commands for a breakpoint.
|
|
</P><P>
|
|
|
|
The commands <SAMP>`echo'</SAMP> and <SAMP>`output'</SAMP> that allow you to print precisely
|
|
controlled output are often useful in silent breakpoints. See section <A HREF="gdb.html#SEC60">12.3 Commands for Controlled Output</A>.
|
|
</P><P>
|
|
|
|
For example, here is how you could use breakpoint commands to print the
|
|
value of <CODE>x</CODE> at entry to <CODE>foo</CODE> whenever it is positive. We
|
|
assume that the newly created breakpoint is number 4; <SAMP>`break'</SAMP> will
|
|
print the number that is assigned.
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>break foo if x>0
|
|
commands 4
|
|
silent
|
|
echo x is\040
|
|
output x
|
|
echo \n
|
|
cont
|
|
end
|
|
</pre></td></tr></table></P><P>
|
|
|
|
One application for breakpoint commands is to correct one bug so you can
|
|
test another. Put a breakpoint just after the erroneous line of code, give
|
|
it a condition to detect the case in which something erroneous has been
|
|
done, and give it commands to assign correct values to any variables that
|
|
need them. End with the <SAMP>`cont'</SAMP> command so that the program does not
|
|
stop, and start with the <SAMP>`silent'</SAMP> command so that no output is
|
|
produced. Here is an example:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>break 403
|
|
commands 5
|
|
silent
|
|
set x = y + 4
|
|
cont
|
|
end
|
|
</pre></td></tr></table></P><P>
|
|
|
|
One deficiency in the operation of automatically continuing breakpoints
|
|
under Unix appears when your program uses raw mode for the terminal.
|
|
GDB switches back to its own terminal modes (not raw) before executing
|
|
commands, and then must switch back to raw mode when your program is
|
|
continued. This causes any pending terminal input to be lost.
|
|
</P><P>
|
|
|
|
In the GNU system, this will be fixed by changing the behavior of
|
|
terminal modes.
|
|
</P><P>
|
|
|
|
Under Unix, when you have this problem, you might be able to get around
|
|
it by putting your actions into the breakpoint condition instead of
|
|
commands. For example
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>condition 5 (x = y + 4), 0
|
|
</pre></td></tr></table></P><P>
|
|
|
|
is a condition expression (See section <A HREF="gdb.html#SEC41">9.1 Expressions</A>) that will change <CODE>x</CODE>
|
|
as needed, then always have the value 0 so the program will not stop.
|
|
Loss of input is avoided here because break conditions are evaluated
|
|
without changing the terminal modes. When you want to have nontrivial
|
|
conditions for performing the side effects, the operators <SAMP>`&&'</SAMP>,
|
|
<SAMP>`||'</SAMP> and <SAMP>`? <small>...</small> :'</SAMP> may be useful.
|
|
</P><P>
|
|
|
|
<A NAME="Error in Breakpoints"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC28"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC27"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC21"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 6.2.6 "Cannot Insert Breakpoints" Error </H3>
|
|
<!--docid::SEC28::-->
|
|
<P>
|
|
|
|
Under some Unix systems, breakpoints cannot be used in a program if any
|
|
other process is running that program. Attempting to run or continue
|
|
the program with a breakpoint in this case will cause GDB to stop it.
|
|
</P><P>
|
|
|
|
When this happens, you have three ways to proceed:
|
|
</P><P>
|
|
|
|
<OL>
|
|
<LI>
|
|
Remove or disable the breakpoints, then continue.
|
|
<P>
|
|
|
|
<LI>
|
|
Suspend GDB, and copy the file containing the program to a new name.
|
|
Resume GDB and use the <SAMP>`exec-file'</SAMP> command to specify that GDB
|
|
should run the program under that name. Then start the program again.
|
|
<P>
|
|
|
|
<LI>
|
|
Recompile the program so that the text is non-sharable (a.out format
|
|
OMAGIC).
|
|
</OL>
|
|
<P>
|
|
|
|
<A NAME="Continuing"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC29"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC28"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC30"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC22"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 6.3 Continuing </H2>
|
|
<!--docid::SEC29::-->
|
|
<P>
|
|
|
|
After your program stops, most likely you will want it to run some more if
|
|
the bug you are looking for has not happened yet.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>cont</CODE>
|
|
<DD><A NAME="IDX54"></A>
|
|
Continue running the program at the place where it stopped.
|
|
</DL>
|
|
<P>
|
|
|
|
If the program stopped at a breakpoint, the place to continue running
|
|
is the address of the breakpoint. You might expect that continuing would
|
|
just stop at the same breakpoint immediately. In fact, <SAMP>`cont'</SAMP>
|
|
takes special care to prevent that from happening. You do not need
|
|
to clear the breakpoint to proceed through it after stopping at it.
|
|
</P><P>
|
|
|
|
You can, however, specify an ignore-count for the breakpoint that the
|
|
program stopped at, by means of an argument to the <SAMP>`cont'</SAMP> command.
|
|
See section <A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A>.
|
|
</P><P>
|
|
|
|
If the program stopped because of a signal other than <CODE>SIGINT</CODE> or
|
|
<CODE>SIGTRAP</CODE>, continuing will cause the program to see that signal.
|
|
You may not want this to happen. For example, if the program stopped
|
|
due to some sort of memory reference error, you might store correct
|
|
values into the erroneous variables and continue, hoping to see more
|
|
execution; but the program would probably terminate immediately as
|
|
a result of the fatal signal once it sees the signal. To prevent this,
|
|
you can continue with <SAMP>`signal 0'</SAMP>. See section <A HREF="gdb.html#SEC55">11.3 Giving the Program a Signal</A>. You can
|
|
also act in advance to prevent the program from seeing certain kinds
|
|
of signals, using the <SAMP>`handle'</SAMP> command (see section <A HREF="gdb.html#SEC21">6.1 Signals</A>).
|
|
</P><P>
|
|
|
|
<A NAME="Stepping"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC30"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC29"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 6.4 Stepping </H2>
|
|
<!--docid::SEC30::-->
|
|
<P>
|
|
|
|
<A NAME="IDX55"></A>
|
|
<EM>Stepping</EM> means setting your program in motion for a limited time, so
|
|
that control will return automatically to the debugger after one line of
|
|
code or one machine instruction. Breakpoints are active during stepping
|
|
and the program will stop for them even if it has not gone as far as the
|
|
stepping command specifies.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>step</CODE>
|
|
<DD><A NAME="IDX56"></A>
|
|
Proceed the program until control reaches a different line, then stop
|
|
it and return to the debugger. This command is abbreviated <SAMP>`s'</SAMP>.
|
|
<P>
|
|
|
|
<DT><CODE>step <VAR>count</VAR></CODE>
|
|
<DD>Proceed as in <SAMP>`step'</SAMP>, but do so <VAR>count</VAR> times. If a breakpoint
|
|
or a signal not related to stepping is reached before <VAR>count</VAR> steps,
|
|
stepping stops right away.
|
|
<P>
|
|
|
|
This command may be given when control is within a routine for which
|
|
there is no debugging information. In that case, execution will proceed
|
|
until control reaches a different routine, or is about to return from
|
|
this routine. An argument repeats this action.
|
|
</P><P>
|
|
|
|
<DT><CODE>next</CODE>
|
|
<DD><A NAME="IDX57"></A>
|
|
Similar to <SAMP>`step'</SAMP>, but any function calls appearing within the line of
|
|
code are executed without stopping. Execution stops when control reaches a
|
|
different line of code at the stack level which was executing when the
|
|
<SAMP>`next'</SAMP> command was given. This command is abbreviated <SAMP>`n'</SAMP>.
|
|
<P>
|
|
|
|
An argument is a repeat count, as in <SAMP>`step'</SAMP>.
|
|
</P><P>
|
|
|
|
<SAMP>`next'</SAMP> within a routine without debugging information acts as does
|
|
<SAMP>`step'</SAMP>, but any function calls appearing within the code of the
|
|
routine are executed without stopping.
|
|
</P><P>
|
|
|
|
<DT><CODE>finish</CODE>
|
|
<DD><A NAME="IDX58"></A>
|
|
Continue running until just after the selected stack frame returns
|
|
(or until there is some other reason to stop, such as a fatal signal
|
|
or a breakpoint). Print value returned by the selected stack frame (if
|
|
any).
|
|
<P>
|
|
|
|
Contrast this with the <SAMP>`return'</SAMP> command (see section <A HREF="gdb.html#SEC56">11.4 Returning from a Function</A>).
|
|
</P><P>
|
|
|
|
<DT><CODE>until</CODE>
|
|
<DD><A NAME="IDX59"></A>
|
|
Proceed the program until control reaches a line greater than the current
|
|
line, then stop is and return to the debugger. Control is also returned to
|
|
the debugger if the program exits the current stack frame. Note that this
|
|
form of the command uses single stepping, and hence is slower than
|
|
<SAMP>`until'</SAMP> with an argument. This command is abbreviated <SAMP>`u'</SAMP>.
|
|
<P>
|
|
|
|
<DT><CODE>until <VAR>location</VAR></CODE>
|
|
<DD>Proceed the program until either the specified location is reached, or the
|
|
current (innermost) stack frame returns. This form of the command uses
|
|
breakpoints, and hence is quicker than <SAMP>`until'</SAMP> without an argument.
|
|
<P>
|
|
|
|
<DT><CODE>stepi</CODE>
|
|
<DD><DT><CODE>si</CODE>
|
|
<DD><A NAME="IDX60"></A>
|
|
<A NAME="IDX61"></A>
|
|
Proceed one machine instruction, then stop and return to the debugger.
|
|
<P>
|
|
|
|
It is often useful to do <SAMP>`display/i $pc'</SAMP> when stepping by machine
|
|
instructions. This will cause the next instruction to be executed to
|
|
be displayed automatically at each stop. See section <A HREF="gdb.html#SEC46">9.5 Automatic Display</A>.
|
|
</P><P>
|
|
|
|
An argument is a repeat count, as in <SAMP>`step'</SAMP>.
|
|
</P><P>
|
|
|
|
<DT><CODE>nexti</CODE>
|
|
<DD><DT><CODE>ni</CODE>
|
|
<DD><A NAME="IDX62"></A>
|
|
<A NAME="IDX63"></A>
|
|
Proceed one machine instruction, but if it is a subroutine call,
|
|
proceed until the subroutine returns.
|
|
<P>
|
|
|
|
An argument is a repeat count, as in <SAMP>`next'</SAMP>.
|
|
</DL>
|
|
<P>
|
|
|
|
A typical technique for using stepping is to put a breakpoint
|
|
(see section <A HREF="gdb.html#SEC22">6.2 Breakpoints</A>) at the beginning of the function or the section of
|
|
the program in which a problem is believed to lie, and then step through
|
|
the suspect area, examining the variables that are interesting, until the
|
|
problem happens.
|
|
</P><P>
|
|
|
|
The <SAMP>`cont'</SAMP> command can be used after stepping to resume execution
|
|
until the next breakpoint or signal.
|
|
</P><P>
|
|
|
|
<A NAME="Stack"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC31"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC30"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC32"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC20"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 7. Examining the Stack </H1>
|
|
<!--docid::SEC31::-->
|
|
<P>
|
|
|
|
When your program has stopped, the first thing you need to know is where it
|
|
stopped and how it got there.
|
|
</P><P>
|
|
|
|
<A NAME="IDX64"></A>
|
|
Each time your program performs a function call, the information about
|
|
where in the program the call was made from is saved in a block of data
|
|
called a <EM>stack frame</EM>. The frame also contains the arguments of the
|
|
call and the local variables of the function that was called. All the
|
|
stack frames are allocated in a region of memory called the <EM>call
|
|
stack</EM>.
|
|
</P><P>
|
|
|
|
When your program stops, the GDB commands for examining the stack allow you
|
|
to see all of this information.
|
|
</P><P>
|
|
|
|
One of the stack frames is <EM>selected</EM> by GDB and many GDB commands
|
|
refer implicitly to the selected frame. In particular, whenever you ask
|
|
GDB for the value of a variable in the program, the value is found in the
|
|
selected frame. There are special GDB commands to select whichever frame
|
|
you are interested in.
|
|
</P><P>
|
|
|
|
When the program stops, GDB automatically selects the currently executing
|
|
frame and describes it briefly as the <SAMP>`frame'</SAMP> command does
|
|
(see section <A HREF="gdb.html#SEC35">Info</A>).
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Explanation of stack frames and terminology.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC33">7.2 Backtraces</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Summarizing many frames at once.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">How to select a stack frame.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC35">7.4 Information on a Frame</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Commands to print information on stack frames.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Frames"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC32"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC33"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 7.1 Stack Frames </H2>
|
|
<!--docid::SEC32::-->
|
|
<P>
|
|
|
|
<A NAME="IDX65"></A>
|
|
The call stack is divided up into contiguous pieces called <EM>frames</EM>;
|
|
each frame is the data associated with one call to one function. The frame
|
|
contains the arguments given to the function, the function's local
|
|
variables, and the address at which the function is executing.
|
|
</P><P>
|
|
|
|
<A NAME="IDX66"></A>
|
|
<A NAME="IDX67"></A>
|
|
<A NAME="IDX68"></A>
|
|
When your program is started, the stack has only one frame, that of the
|
|
function <CODE>main</CODE>. This is called the <EM>initial</EM> frame or the
|
|
<EM>outermost</EM> frame. Each time a function is called, a new frame is
|
|
made. Each time a function returns, the frame for that function invocation
|
|
is eliminated. If a function is recursive, there can be many frames for
|
|
the same function. The frame for the function in which execution is
|
|
actually occurring is called the <EM>innermost</EM> frame. This is the most
|
|
recently created of all the stack frames that still exist.
|
|
</P><P>
|
|
|
|
<A NAME="IDX69"></A>
|
|
Inside your program, stack frames are identified by their addresses. A
|
|
stack frame consists of many bytes, each of which has its own address; each
|
|
kind of computer has a convention for choosing one of those bytes whose
|
|
address serves as the address of the frame. Usually this address is kept
|
|
in a register called the <EM>frame pointer register</EM> while execution is
|
|
going on in that frame.
|
|
</P><P>
|
|
|
|
<A NAME="IDX70"></A>
|
|
GDB assigns numbers to all existing stack frames, starting with zero for
|
|
the innermost frame, one for the frame that called it, and so on upward.
|
|
These numbers do not really exist in your program; they are to give you a
|
|
way of talking about stack frames in GDB commands.
|
|
</P><P>
|
|
|
|
<A NAME="IDX71"></A>
|
|
Many GDB commands refer implicitly to one stack frame. GDB records a stack
|
|
frame that is called the <EM>selected</EM> stack frame; you can select any
|
|
frame using one set of GDB commands, and then other commands will operate
|
|
on that frame. When your program stops, GDB automatically selects the
|
|
innermost frame.
|
|
</P><P>
|
|
|
|
<A NAME="Backtrace"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC33"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC32"> < </A>]</TD>
|
|
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|
|
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|
|
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|
|
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|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 7.2 Backtraces </H2>
|
|
<!--docid::SEC33::-->
|
|
<P>
|
|
|
|
A backtrace is a summary of how the program got where it is. It shows one
|
|
line per frame, for many frames, starting with the currently executing
|
|
frame (frame zero), followed by its caller (frame one), and on up the
|
|
stack.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>backtrace</CODE>
|
|
<DD><DT><CODE>bt</CODE>
|
|
<DD>Print a backtrace of the entire stack: one line per frame for all
|
|
frames in the stack.
|
|
<P>
|
|
|
|
You can stop the backtrace at any time by typing the system interrupt
|
|
character, normally <KBD>Control-C</KBD>.
|
|
</P><P>
|
|
|
|
<DT><CODE>backtrace <VAR>n</VAR></CODE>
|
|
<DD><DT><CODE>bt <VAR>n</VAR></CODE>
|
|
<DD>Similar, but stop after <VAR>n</VAR> frames.
|
|
<P>
|
|
|
|
<DT><CODE>backtrace <VAR>-n</VAR></CODE>
|
|
<DD><DT><CODE>bt <VAR>-n</VAR></CODE>
|
|
<DD>Similar, but print the outermost <VAR>n</VAR> frames instead of the
|
|
innermost.
|
|
</DL>
|
|
<P>
|
|
|
|
Each line in a backtrace shows the frame number, the program counter, the
|
|
function and its arguments, and the source file name and line number (if
|
|
known). The program counter is omitted if is the beginning of the code for
|
|
the source line. This is the same as the first of the two lines printed
|
|
when you select a frame.
|
|
</P><P>
|
|
|
|
<A NAME="Selection"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC34"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC33"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC35"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 7.3 Selecting a Frame </H2>
|
|
<!--docid::SEC34::-->
|
|
<P>
|
|
|
|
Most commands for examining the stack and other data in the program work on
|
|
whichever stack frame is selected at the moment. Here are the commands for
|
|
selecting a stack frame; all of them finish by printing a brief description
|
|
of the stack frame just selected.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>frame <VAR>n</VAR></CODE>
|
|
<DD><A NAME="IDX72"></A>
|
|
Select frame number <VAR>n</VAR>. Recall that frame zero is the innermost
|
|
(currently executing) frame, frame one is the frame that called the
|
|
innermost one, and so on. The highest-numbered frame is <CODE>main</CODE>'s
|
|
frame.
|
|
<P>
|
|
|
|
<DT><CODE>frame <VAR>addr</VAR></CODE>
|
|
<DD>Select the frame at address <VAR>addr</VAR>. This is useful mainly if the
|
|
chaining of stack frames has been damaged by a bug, making it
|
|
impossible for GDB to assign numbers properly to all frames. In
|
|
addition, this can be useful when the program has multiple stacks and
|
|
switches between them.
|
|
<P>
|
|
|
|
<DT><CODE>up <VAR>n</VAR></CODE>
|
|
<DD><A NAME="IDX73"></A>
|
|
Select the frame <VAR>n</VAR> frames up from the frame previously selected.
|
|
For positive numbers <VAR>n</VAR>, this advances toward the outermost
|
|
frame, to higher frame numbers, to frames that have existed longer.
|
|
<VAR>n</VAR> defaults to one.
|
|
<P>
|
|
|
|
<DT><CODE>down <VAR>n</VAR></CODE>
|
|
<DD><A NAME="IDX74"></A>
|
|
Select the frame <VAR>n</VAR> frames down from the frame previously
|
|
selected. For positive numbers <VAR>n</VAR>, this advances toward the
|
|
innermost frame, to lower frame numbers, to frames that were created
|
|
more recently. <VAR>n</VAR> defaults to one.
|
|
</DL>
|
|
<P>
|
|
|
|
All of these commands end by printing some information on the frame that
|
|
has been selected: the frame number, the function name, the arguments, the
|
|
source file and line number of execution in that frame, and the text of
|
|
that source line. For example:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>#3 main (argc=3, argv=??, env=??) at main.c, line 67
|
|
67 read_input_file (argv[i]);
|
|
</pre></td></tr></table></P><P>
|
|
|
|
After such a printout, the <SAMP>`list'</SAMP> command with no arguments will print
|
|
ten lines centered on the point of execution in the frame. See section <A HREF="gdb.html#SEC37">8.1 Printing Source Lines</A>.
|
|
</P><P>
|
|
|
|
<A NAME="Frame Info"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC35"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC34"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 7.4 Information on a Frame </H2>
|
|
<!--docid::SEC35::-->
|
|
<P>
|
|
|
|
There are several other commands to print information about the selected
|
|
stack frame.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>frame</CODE>
|
|
<DD>This command prints a brief description of the selected stack frame.
|
|
It can be abbreviated <SAMP>`f'</SAMP>. With an argument, this command is
|
|
used to select a stack frame; with no argument, it does not change
|
|
which frame is selected, but still prints the same information.
|
|
<P>
|
|
|
|
<DT><CODE>info frame</CODE>
|
|
<DD><A NAME="IDX75"></A>
|
|
This command prints a verbose description of the selected stack frame,
|
|
including the address of the frame, the addresses of the next frame in
|
|
(called by this frame) and the next frame out (caller of this frame),
|
|
the address of the frame's arguments, the program counter saved in it
|
|
(the address of execution in the caller frame), and which registers
|
|
were saved in the frame. The verbose description is useful when
|
|
something has gone wrong that has made the stack format fail to fit
|
|
the usual conventions.
|
|
<P>
|
|
|
|
<DT><CODE>info frame <VAR>addr</VAR></CODE>
|
|
<DD>Print a verbose description of the frame at address <VAR>addr</VAR>,
|
|
without selecting that frame. The selected frame remains unchanged by
|
|
this command.
|
|
<P>
|
|
|
|
<DT><CODE>info args</CODE>
|
|
<DD><A NAME="IDX76"></A>
|
|
Print the arguments of the selected frame, each on a separate line.
|
|
<P>
|
|
|
|
<DT><CODE>info locals</CODE>
|
|
<DD><A NAME="IDX77"></A>
|
|
Print the local variables of the selected frame, each on a separate
|
|
line. These are all variables declared static or automatic within all
|
|
program blocks that execution in this frame is currently inside of.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Source"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC36"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC35"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC37"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC31"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 8. Examining Source Files </H1>
|
|
<!--docid::SEC36::-->
|
|
<P>
|
|
|
|
GDB knows which source files your program was compiled from, and
|
|
can print parts of their text. When your program stops, GDB
|
|
spontaneously prints the line it stopped in. Likewise, when you
|
|
select a stack frame (see section <A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A>), GDB prints the line
|
|
which execution in that frame has stopped in. You can also
|
|
print parts of source files by explicit command.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC37">8.1 Printing Source Lines</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Using the <SAMP>`list'</SAMP> command to print source files.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC38">8.2 Searching Source Files</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Commands for searching source files.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC39">8.3 Specifying Source Directories</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying the directories to search for source files.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="List"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC37"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC38"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 8.1 Printing Source Lines </H2>
|
|
<!--docid::SEC37::-->
|
|
<P>
|
|
|
|
<A NAME="IDX78"></A>
|
|
To print lines from a source file, use the <SAMP>`list'</SAMP> command
|
|
(abbreviated <SAMP>`l'</SAMP>). There are several ways to specify what part
|
|
of the file you want to print.
|
|
</P><P>
|
|
|
|
Here are the forms of the <SAMP>`list'</SAMP> command most commonly used:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>list <VAR>linenum</VAR></CODE>
|
|
<DD>Print ten lines centered around line number <VAR>linenum</VAR> in the
|
|
current source file.
|
|
<P>
|
|
|
|
<DT><CODE>list <VAR>function</VAR></CODE>
|
|
<DD>Print ten lines centered around the beginning of function
|
|
<VAR>function</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>list</CODE>
|
|
<DD>Print ten more lines. If the last lines printed were printed with a
|
|
<SAMP>`list'</SAMP> command, this prints ten lines following the last lines
|
|
printed; however, if the last line printed was a solitary line printed
|
|
as part of displaying a stack frame (see section <A HREF="gdb.html#SEC31">7. Examining the Stack</A>), this prints ten
|
|
lines centered around that line.
|
|
<P>
|
|
|
|
<DT><CODE>list -</CODE>
|
|
<DD>Print ten lines just before the lines last printed.
|
|
</DL>
|
|
<P>
|
|
|
|
Repeating a <SAMP>`list'</SAMP> command with <KBD>RET</KBD> discards the argument,
|
|
so it is equivalent to typing just <SAMP>`list'</SAMP>. This is more useful
|
|
than listing the same lines again. An exception is made for an
|
|
argument of <SAMP>`-'</SAMP>; that argument is preserved in repetition so that
|
|
each repetition moves up in the file.
|
|
</P><P>
|
|
|
|
In general, the <SAMP>`list'</SAMP> command expects you to supply zero, one or two
|
|
<EM>linespecs</EM>. Linespecs specify source lines; there are several ways
|
|
of writing them but the effect is always to specify some source line.
|
|
Here is a complete description of the possible arguments for <SAMP>`list'</SAMP>:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>list <VAR>linespec</VAR></CODE>
|
|
<DD>Print ten lines centered around the line specified by <VAR>linespec</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>list <VAR>first</VAR>,<VAR>last</VAR></CODE>
|
|
<DD>Print lines from <VAR>first</VAR> to <VAR>last</VAR>. Both arguments are
|
|
linespecs.
|
|
<P>
|
|
|
|
<DT><CODE>list ,<VAR>last</VAR></CODE>
|
|
<DD>Print ten lines ending with <VAR>last</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>list <VAR>first</VAR>,</CODE>
|
|
<DD>Print ten lines starting with <VAR>first</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>list +</CODE>
|
|
<DD>Print ten lines just after the lines last printed.
|
|
<P>
|
|
|
|
<DT><CODE>list -</CODE>
|
|
<DD>Print ten lines just before the lines last printed.
|
|
<P>
|
|
|
|
<DT><CODE>list</CODE>
|
|
<DD>As described in the preceding table.
|
|
</DL>
|
|
<P>
|
|
|
|
Here are the ways of specifying a single source line--all the
|
|
kinds of linespec.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><VAR>linenum</VAR>
|
|
<DD>Specifies line <VAR>linenum</VAR> of the current source file.
|
|
When a <SAMP>`list'</SAMP> command has two linespecs, this refers to
|
|
the same source file as the first linespec.
|
|
<P>
|
|
|
|
<DT>+<VAR>offset</VAR>
|
|
<DD>Specifies the line <VAR>offset</VAR> lines after the last line printed.
|
|
When used as the second linespec in a <SAMP>`list'</SAMP> command that has
|
|
two, this specifies the line <VAR>offset</VAR> lines down from the
|
|
first linespec.
|
|
<P>
|
|
|
|
<DT>-<VAR>offset</VAR>
|
|
<DD>Specifies the line <VAR>offset</VAR> lines before the last line printed.
|
|
<P>
|
|
|
|
<DT><VAR>filename</VAR>:<VAR>linenum</VAR>
|
|
<DD>Specifies line <VAR>linenum</VAR> in the source file <VAR>filename</VAR>.
|
|
<P>
|
|
|
|
<DT><VAR>function</VAR>
|
|
<DD>Specifies the line of the open-brace that begins the body of the
|
|
function <VAR>function</VAR>.
|
|
<P>
|
|
|
|
<DT><VAR>filename</VAR>:<VAR>function</VAR>
|
|
<DD>Specifies the line of the open-brace that begins the body of the
|
|
function <VAR>function</VAR> in the file <VAR>filename</VAR>. The file name is
|
|
needed with a function name only for disambiguation of identically
|
|
named functions in different source files.
|
|
<P>
|
|
|
|
<DT>*<VAR>address</VAR>
|
|
<DD>Specifies the line containing the program address <VAR>address</VAR>.
|
|
<VAR>address</VAR> may be any expression.
|
|
</DL>
|
|
<P>
|
|
|
|
One other command is used to map source lines to program addresses.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>info line <VAR>linenum</VAR></CODE>
|
|
<DD><A NAME="IDX79"></A>
|
|
Print the starting and ending addresses of the compiled code for
|
|
source line <VAR>linenum</VAR>.
|
|
<P>
|
|
|
|
<A NAME="IDX80"></A>
|
|
The default examine address for the <SAMP>`x'</SAMP> command is changed to the
|
|
starting address of the line, so that <SAMP>`x/i'</SAMP> is sufficient to
|
|
begin examining the machine code (see section <A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A>). Also, this address
|
|
is saved as the value of the convenience variable <SAMP>`$_'</SAMP>
|
|
(see section <A HREF="gdb.html#SEC48">9.7 Convenience Variables</A>).
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Search"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC38"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC37"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC39"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 8.2 Searching Source Files </H2>
|
|
<!--docid::SEC38::-->
|
|
<P>
|
|
|
|
There are two commands for searching through the current source file for a
|
|
regular expression.
|
|
</P><P>
|
|
|
|
The command <SAMP>`forward-search <VAR>regexp</VAR>'</SAMP> checks each line, starting
|
|
with the one following the last line listed, for a match for <VAR>regexp</VAR>.
|
|
It lists the line that is found. You can abbreviate the command name
|
|
as <SAMP>`fo'</SAMP>.
|
|
</P><P>
|
|
|
|
The command <SAMP>`reverse-search <VAR>regexp</VAR>'</SAMP> checks each line, starting
|
|
with the one before the last line listed and going backward, for a match
|
|
for <VAR>regexp</VAR>. It lists the line that is found. You can abbreviate
|
|
this command with as little as <SAMP>`rev'</SAMP>.
|
|
</P><P>
|
|
|
|
<A NAME="Source Path"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC39"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC38"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 8.3 Specifying Source Directories </H2>
|
|
<!--docid::SEC39::-->
|
|
<P>
|
|
|
|
<A NAME="IDX81"></A>
|
|
<A NAME="IDX82"></A>
|
|
Executable programs do not record the directories of the source files they
|
|
were compiled from, just the names. GDB remembers a list of directories to
|
|
search for source files; this is called the <EM>source path</EM>. Each time
|
|
GDB wants a source file, it tries all the directories in the list, in the
|
|
order they are present in the list, until it finds a file with the desired
|
|
name.
|
|
</P><P>
|
|
|
|
<A NAME="IDX83"></A>
|
|
When you start GDB, its source path contains just the current working
|
|
directory. To add other directories, use the <SAMP>`directory'</SAMP> command.
|
|
<B>Note that the search path for executable files and the working directory
|
|
are <I>not</I> used for finding source files.</B>
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>directory <VAR>dirname</VAR></CODE>
|
|
<DD>Add directory <VAR>dirname</VAR> to the end of the source path.
|
|
<P>
|
|
|
|
<DT><CODE>directory</CODE>
|
|
<DD>Reset the source path to just the current working directory of GDB.
|
|
This requires confirmation.
|
|
<P>
|
|
|
|
<SAMP>`directory'</SAMP> with no argument can cause source files previously
|
|
found by GDB to be found in a different directory. To make this work
|
|
correctly, this command also clears out the tables GDB maintains
|
|
about the source files it has already found.
|
|
</P><P>
|
|
|
|
<DT><CODE>info directories</CODE>
|
|
<DD><A NAME="IDX84"></A>
|
|
Print the source path: show which directories it contains.
|
|
</DL>
|
|
<P>
|
|
|
|
Because the <SAMP>`directory'</SAMP> command adds to the end of the source path,
|
|
it does not affect any file that GDB has already found. If the source
|
|
path contains directories that you do not want, and these directories
|
|
contain misleading files with names matching your source files, the
|
|
way to correct the situation is as follows:
|
|
</P><P>
|
|
|
|
<OL>
|
|
<LI>
|
|
Choose the directory you want at the beginning of the source path.
|
|
Use the <SAMP>`cd'</SAMP> command to make that the current working directory.
|
|
<P>
|
|
|
|
<LI>
|
|
Use <SAMP>`directory'</SAMP> with no argument to reset the source path to just
|
|
that directory.
|
|
<P>
|
|
|
|
<LI>
|
|
Use <SAMP>`directory'</SAMP> with suitable arguments to add any other
|
|
directories you want in the source path.
|
|
</OL>
|
|
<P>
|
|
|
|
<A NAME="Data"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC40"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC39"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC41"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC36"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 9. Examining Data </H1>
|
|
<!--docid::SEC40::-->
|
|
<P>
|
|
|
|
<A NAME="IDX85"></A>
|
|
<A NAME="IDX86"></A>
|
|
<A NAME="IDX87"></A>
|
|
The usual way of examining data in your program is with the <SAMP>`print'</SAMP>
|
|
command (abbreviated <SAMP>`p'</SAMP>). It evaluates and prints the value of any
|
|
valid expression of the language the program is written in (for now, C).
|
|
You type
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>print <VAR>exp</VAR>
|
|
</pre></td></tr></table></P><P>
|
|
|
|
where <VAR>exp</VAR> is any valid expression, and the value of <VAR>exp</VAR>
|
|
is printed in a format appropriate to its data type.
|
|
</P><P>
|
|
|
|
A more low-level way of examining data is with the <SAMP>`x'</SAMP> command.
|
|
It examines data in memory at a specified address and prints it in a
|
|
specified format.
|
|
</P><P>
|
|
|
|
GDB supports one command to modify the default format of displayed data:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><SAMP>`set array-max'</SAMP>
|
|
<DD><A NAME="IDX88"></A>
|
|
<SAMP>`set array-max'</SAMP> sets the maximum number of elements of an array which
|
|
will be printed. This limit also applies to the display of strings.
|
|
</DL>
|
|
<P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC41">9.1 Expressions</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Expressions that can be computed and printed.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC42">9.2 Program Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Using your program's variables in expressions.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC53">11.1 Assignment to Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Setting your program's variables.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC43">9.3 Artificial Arrays</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Examining part of memory as an array.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC44">9.4 Formats</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Specifying formats for printing values.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Examining memory explicitly.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC46">9.5 Automatic Display</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Printing certain expressions whenever program stops.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC47">9.6 Value History</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Referring to values previously printed.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC48">9.7 Convenience Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Giving names to values for future reference.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC49">9.8 Registers</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Referring to and storing in machine registers.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Expressions"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC41"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC42"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.1 Expressions </H2>
|
|
<!--docid::SEC41::-->
|
|
<P>
|
|
|
|
<A NAME="IDX89"></A>
|
|
Many different GDB commands accept an expression and compute its value.
|
|
Any kind of constant, variable or operator defined by the programming
|
|
language you are using is legal in an expression in GDB. This includes
|
|
conditional expressions, function calls, casts and string constants.
|
|
It unfortunately does not include symbols defined by preprocessor
|
|
#define commands.
|
|
</P><P>
|
|
|
|
Casts are supported in all languages, not just in C, because it is so
|
|
useful to cast a number into a pointer so as to examine a structure
|
|
at that address in memory.
|
|
</P><P>
|
|
|
|
GDB supports three kinds of operator in addition to those of programming
|
|
languages:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>@</CODE>
|
|
<DD><SAMP>`@'</SAMP> is a binary operator for treating parts of memory as arrays.
|
|
See section <A HREF="gdb.html#SEC43">9.3 Artificial Arrays</A>, for more information.
|
|
<P>
|
|
|
|
<DT><CODE>::</CODE>
|
|
<DD><SAMP>`::'</SAMP> allows you to specify a variable in terms of the file or
|
|
function it is defined in. See section <A HREF="gdb.html#SEC42">9.2 Program Variables</A>.
|
|
<P>
|
|
|
|
<DT><CODE>{<VAR>type</VAR>} <VAR>addr</VAR></CODE>
|
|
<DD>Refers to an object of type <VAR>type</VAR> stored at address <VAR>addr</VAR> in
|
|
memory. <VAR>addr</VAR> may be any expression whose value is an integer or
|
|
pointer (but parentheses are required around nonunary operators, just as in
|
|
a cast). This construct is allowed regardless of what kind of data is
|
|
officially supposed to reside at <VAR>addr</VAR>.</DL>
|
|
<P>
|
|
|
|
<A NAME="Variables"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC42"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC41"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC43"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.2 Program Variables </H2>
|
|
<!--docid::SEC42::-->
|
|
<P>
|
|
|
|
The most common kind of expression to use is the name of a variable
|
|
in your program.
|
|
</P><P>
|
|
|
|
Variables in expressions are understood in the selected stack frame
|
|
(see section <A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A>); they must either be global (or static) or be visible
|
|
according to the scope rules of the programming language from the point of
|
|
execution in that frame. This means that in the function
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>foo (a)
|
|
int a;
|
|
{
|
|
bar (a);
|
|
{
|
|
int b = test ();
|
|
bar (b);
|
|
}
|
|
}
|
|
</pre></td></tr></table></P><P>
|
|
|
|
the variable <CODE>a</CODE> is usable whenever the program is executing
|
|
within the function <CODE>foo</CODE>, but the variable <CODE>b</CODE> is visible
|
|
only while the program is executing inside the block in which <CODE>b</CODE>
|
|
is declared.
|
|
</P><P>
|
|
|
|
As a special exception, you can refer to a variable or function whose
|
|
scope is a single source file even if the current execution point is not
|
|
in this file. But it is possible to have more than one such variable
|
|
or function with the same name (if they are in different source files).
|
|
In such a case, it is not defined which one you will get. If you wish,
|
|
you can specify any one of them using the colon-colon construct:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre><VAR>block</VAR>::<VAR>variable</VAR>
|
|
</pre></td></tr></table></P><P>
|
|
|
|
Here <VAR>block</VAR> is the name of the source file whose variable you want.
|
|
</P><P>
|
|
|
|
<A NAME="Arrays"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC43"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC42"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC44"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.3 Artificial Arrays </H2>
|
|
<!--docid::SEC43::-->
|
|
<P>
|
|
|
|
<A NAME="IDX90"></A>
|
|
It is often useful to print out several successive objects of the
|
|
same type in memory; a section of an array, or an array of
|
|
dynamically determined size for which only a pointer exists in the
|
|
program.
|
|
</P><P>
|
|
|
|
This can be done by constructing an <EM>artificial array</EM> with the
|
|
binary operator <SAMP>`@'</SAMP>. The left operand of <SAMP>`@'</SAMP> should be
|
|
the first element of the desired array, as an individual object.
|
|
The right operand should be the length of the array. The result is
|
|
an array value whose elements are all of the type of the left argument.
|
|
The first element is actually the left argument; the second element
|
|
comes from bytes of memory immediately following those that hold the
|
|
first element, and so on. Here is an example. If a program says
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>int *array = (int *) malloc (len * sizeof (int));
|
|
</pre></td></tr></table></P><P>
|
|
|
|
you can print the contents of <CODE>array</CODE> with
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>p *array@len
|
|
</pre></td></tr></table></P><P>
|
|
|
|
The left operand of <SAMP>`@'</SAMP> must reside in memory. Array values made
|
|
with <SAMP>`@'</SAMP> in this way behave just like other arrays in terms of
|
|
subscripting, and are coerced to pointers when used in expressions.
|
|
(It would probably appear in an expression via the value history,
|
|
after you had printed it out.)
|
|
</P><P>
|
|
|
|
<A NAME="Formats"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC44"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC43"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC45"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.4 Formats </H2>
|
|
<!--docid::SEC44::-->
|
|
<P>
|
|
|
|
<A NAME="IDX91"></A>
|
|
<A NAME="IDX92"></A>
|
|
GDB normally prints all values according to their data types. Sometimes
|
|
this is not what you want. For example, you might want to print a number
|
|
in hex, or a pointer in decimal. Or you might want to view data in memory
|
|
at a certain address as a character string or an instruction. These things
|
|
can be done with <EM>output formats</EM>.
|
|
</P><P>
|
|
|
|
The simplest use of output formats is to say how to print a value
|
|
already computed. This is done by starting the arguments of the
|
|
<SAMP>`print'</SAMP> command with a slash and a format letter. The format
|
|
letters supported are:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><SAMP>`x'</SAMP>
|
|
<DD>Regard the bits of the value as an integer, and print the integer in
|
|
hexadecimal.
|
|
<P>
|
|
|
|
<DT><SAMP>`d'</SAMP>
|
|
<DD>Print as integer in signed decimal.
|
|
<P>
|
|
|
|
<DT><SAMP>`u'</SAMP>
|
|
<DD>Print as integer in unsigned decimal.
|
|
<P>
|
|
|
|
<DT><SAMP>`o'</SAMP>
|
|
<DD>Print as integer in octal.
|
|
<P>
|
|
|
|
<DT><SAMP>`a'</SAMP>
|
|
<DD>Print as an address, both absolute in hex and then relative
|
|
to a symbol defined as an address below it.
|
|
<P>
|
|
|
|
<DT><SAMP>`c'</SAMP>
|
|
<DD>Regard as an integer and print it as a character constant.
|
|
<P>
|
|
|
|
<DT><SAMP>`f'</SAMP>
|
|
<DD>Regard the bits of the value as a floating point number and print
|
|
using typical floating point syntax.
|
|
</DL>
|
|
<P>
|
|
|
|
For example, to print the program counter in hex (see section <A HREF="gdb.html#SEC49">9.8 Registers</A>), type
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>p/x $pc
|
|
</pre></td></tr></table></P><P>
|
|
|
|
Note that no space is required before the slash; this is because command
|
|
names in GDB cannot contain a slash.
|
|
</P><P>
|
|
|
|
To reprint the last value in the value history with a different format,
|
|
you can use the <SAMP>`print'</SAMP> command with just a format and no
|
|
expression. For example, <SAMP>`p/x'</SAMP> reprints the last value in hex.
|
|
</P><P>
|
|
|
|
<A NAME="Memory"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC45"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC44"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC46"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 9.4.1 Examining Memory </H3>
|
|
<!--docid::SEC45::-->
|
|
<P>
|
|
|
|
<A NAME="IDX93"></A>
|
|
<A NAME="IDX94"></A>
|
|
The command <SAMP>`x'</SAMP> (for `examine') can be used to examine memory under
|
|
explicit control of formats, without reference to the program's data types.
|
|
</P><P>
|
|
|
|
<SAMP>`x'</SAMP> is followed by a slash and an output format specification,
|
|
followed by an expression for an address. The expression need not have
|
|
a pointer value (though it may); it is used as an integer, as the
|
|
address of a byte of memory. See section <A HREF="gdb.html#SEC41">9.1 Expressions</A> for more information
|
|
on expressions.
|
|
</P><P>
|
|
|
|
The output format in this case specifies both how big a unit of memory
|
|
to examine and how to print the contents of that unit. It is done
|
|
with one or two of the following letters:
|
|
</P><P>
|
|
|
|
These letters specify just the size of unit to examine:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><SAMP>`b'</SAMP>
|
|
<DD>Examine individual bytes.
|
|
<P>
|
|
|
|
<DT><SAMP>`h'</SAMP>
|
|
<DD>Examine halfwords (two bytes each).
|
|
<P>
|
|
|
|
<DT><SAMP>`w'</SAMP>
|
|
<DD>Examine words (four bytes each).
|
|
<P>
|
|
|
|
<A NAME="IDX95"></A>
|
|
Many assemblers and cpu designers still use `word' for a 16-bit quantity,
|
|
as a holdover from specific predecessor machines of the 1970's that really
|
|
did use two-byte words. But more generally the term `word' has always
|
|
referred to the size of quantity that a machine normally operates on and
|
|
stores in its registers. This is 32 bits for all the machines that GNU
|
|
runs on.
|
|
</P><P>
|
|
|
|
<DT><SAMP>`g'</SAMP>
|
|
<DD>Examine giant words (8 bytes).
|
|
</DL>
|
|
<P>
|
|
|
|
These letters specify just the way to print the contents:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><SAMP>`x'</SAMP>
|
|
<DD>Print as integers in unsigned hexadecimal.
|
|
<P>
|
|
|
|
<DT><SAMP>`d'</SAMP>
|
|
<DD>Print as integers in signed decimal.
|
|
<P>
|
|
|
|
<DT><SAMP>`u'</SAMP>
|
|
<DD>Print as integers in unsigned decimal.
|
|
<P>
|
|
|
|
<DT><SAMP>`o'</SAMP>
|
|
<DD>Print as integers in unsigned octal.
|
|
<P>
|
|
|
|
<DT><SAMP>`a'</SAMP>
|
|
<DD>Print as an address, both absolute in hex and then relative
|
|
to a symbol defined as an address below it.
|
|
<P>
|
|
|
|
<DT><SAMP>`c'</SAMP>
|
|
<DD>Print as character constants.
|
|
<P>
|
|
|
|
<DT><SAMP>`f'</SAMP>
|
|
<DD>Print as floating point. This works only with sizes <SAMP>`w'</SAMP> and
|
|
<SAMP>`g'</SAMP>.
|
|
<P>
|
|
|
|
<DT><SAMP>`s'</SAMP>
|
|
<DD>Print a null-terminated string of characters. The specified unit size
|
|
is ignored; instead, the unit is however many bytes it takes to reach
|
|
a null character (including the null character).
|
|
<P>
|
|
|
|
<DT><SAMP>`i'</SAMP>
|
|
<DD>Print a machine instruction in assembler syntax (or nearly). The
|
|
specified unit size is ignored; the number of bytes in an instruction
|
|
varies depending on the type of machine, the opcode and the addressing
|
|
modes used.
|
|
</DL>
|
|
<P>
|
|
|
|
If either the manner of printing or the size of unit fails to be specified,
|
|
the default is to use the same one that was used last. If you don't want
|
|
to use any letters after the slash, you can omit the slash as well.
|
|
</P><P>
|
|
|
|
You can also omit the address to examine. Then the address used is
|
|
just after the last unit examined. This is why string and instruction
|
|
formats actually compute a unit-size based on the data: so that the
|
|
next string or instruction examined will start in the right place.
|
|
The <SAMP>`print'</SAMP> command sometimes sets the default address for
|
|
the <SAMP>`x'</SAMP> command; when the value printed resides in memory, the
|
|
default is set to examine the same location. <SAMP>`info line'</SAMP> also
|
|
sets the default for <SAMP>`x'</SAMP>, to the address of the start of the
|
|
machine code for the specified line and <SAMP>`info breakpoints'</SAMP> sets
|
|
it to the address of the last breakpoint listed.
|
|
</P><P>
|
|
|
|
When you use <KBD>RET</KBD> to repeat an <SAMP>`x'</SAMP> command, it does not repeat
|
|
exactly the same: the address specified previously (if any) is ignored, so
|
|
that the repeated command examines the successive locations in memory
|
|
rather than the same ones.
|
|
</P><P>
|
|
|
|
You can examine several consecutive units of memory with one command by
|
|
writing a repeat-count after the slash (before the format letters, if any).
|
|
The repeat count must be a decimal integer. It has the same effect as
|
|
repeating the <SAMP>`x'</SAMP> command that many times except that the output may
|
|
be more compact with several units per line.
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>x/10i $pc
|
|
</pre></td></tr></table></P><P>
|
|
|
|
Prints ten instructions starting with the one to be executed next in the
|
|
selected frame. After doing this, you could print another ten following
|
|
instructions with
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>x/10
|
|
</pre></td></tr></table></P><P>
|
|
|
|
in which the format and address are allowed to default.
|
|
</P><P>
|
|
|
|
<A NAME="IDX96"></A>
|
|
<A NAME="IDX97"></A>
|
|
The addresses and contents printed by the <SAMP>`x'</SAMP> command are not put in
|
|
the value history because there is often too much of them and they would
|
|
get in the way. Instead, GDB makes these values available for subsequent
|
|
use in expressions as values of the convenience variables <SAMP>`$_'</SAMP> and
|
|
<SAMP>`$__'</SAMP>.
|
|
</P><P>
|
|
|
|
After an <SAMP>`x'</SAMP> command, the last address examined is available for use
|
|
in expressions in the convenience variable <SAMP>`$_'</SAMP>. The contents of that
|
|
address, as examined, are available in the convenience variable <SAMP>`$__'</SAMP>.
|
|
</P><P>
|
|
|
|
If the <SAMP>`x'</SAMP> command has a repeat count, the address and contents saved
|
|
are from the last memory unit printed; this is not the same as the last
|
|
address printed if several units were printed on the last line of output.
|
|
</P><P>
|
|
|
|
<A NAME="Auto Display"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC46"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC45"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC47"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.5 Automatic Display </H2>
|
|
<!--docid::SEC46::-->
|
|
<P>
|
|
|
|
If you find that you want to print the value of an expression frequently
|
|
(to see how it changes), you might want to add it to the <EM>automatic
|
|
display list</EM> so that GDB will print its value each time the program stops.
|
|
Each expression added to the list is given a number to identify it;
|
|
to remove an expression from the list, you specify that number.
|
|
The automatic display looks like this:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>2: foo = 38
|
|
3: bar[5] = (struct hack *) 0x3804
|
|
</pre></td></tr></table></P><P>
|
|
|
|
showing item numbers, expressions and their current values.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>display <VAR>exp</VAR></CODE>
|
|
<DD><A NAME="IDX98"></A>
|
|
Add the expression <VAR>exp</VAR> to the list of expressions to display
|
|
each time the program stops. See section <A HREF="gdb.html#SEC41">9.1 Expressions</A>.
|
|
<P>
|
|
|
|
<DT><CODE>display/<VAR>fmt</VAR> <VAR>exp</VAR></CODE>
|
|
<DD>For <VAR>fmt</VAR> specifying only a display format and not a size or
|
|
count, add the expression <VAR>exp</VAR> to the auto-display list but
|
|
arranges to display it each time in the specified format <VAR>fmt</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>display/<VAR>fmt</VAR> <VAR>addr</VAR></CODE>
|
|
<DD>For <VAR>fmt</VAR> <SAMP>`i'</SAMP> or <SAMP>`s'</SAMP>, or including a unit-size or a
|
|
number of units, add the expression <VAR>addr</VAR> as a memory address to
|
|
be examined each time the program stops. Examining means in effect
|
|
doing <SAMP>`x/<VAR>fmt</VAR> <VAR>addr</VAR>'</SAMP>. See section <A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A>.
|
|
<P>
|
|
|
|
<DT><CODE>undisplay <VAR>dnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX99"></A>
|
|
<DT><CODE>delete display <VAR>dnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX100"></A>
|
|
Remove item numbers <VAR>dnums</VAR> from the list of expressions to display.
|
|
<P>
|
|
|
|
<DT><CODE>disable display <VAR>dnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX101"></A>
|
|
Disable the display of item numbers <VAR>dnums</VAR>. A disabled display item
|
|
has no effect but is not forgotten. It may be later enabled.
|
|
<P>
|
|
|
|
<DT><CODE>enable display <VAR>dnums</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX102"></A>
|
|
Enable display of item numbers <VAR>dnums</VAR>. It becomes effective once
|
|
again in auto display of its expression, until you specify otherwise.
|
|
<P>
|
|
|
|
<DT><CODE>display</CODE>
|
|
<DD>Display the current values of the expressions on the list, just as is
|
|
done when the program stops.
|
|
<P>
|
|
|
|
<DT><CODE>info display</CODE>
|
|
<DD><A NAME="IDX103"></A>
|
|
Print the list of expressions to display automatically, each one
|
|
with its item number, but without showing the values.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Value History"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC47"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC46"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC48"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.6 Value History </H2>
|
|
<!--docid::SEC47::-->
|
|
<P>
|
|
|
|
<A NAME="IDX104"></A>
|
|
Every value printed by the <SAMP>`print'</SAMP> command is saved for the entire
|
|
session in GDB's <EM>value history</EM> so that you can refer to it in
|
|
other expressions.
|
|
</P><P>
|
|
|
|
<A NAME="IDX105"></A>
|
|
<A NAME="IDX106"></A>
|
|
The values printed are given <EM>history numbers</EM> for you to refer to them
|
|
by. These are successive integers starting with 1. <SAMP>`print'</SAMP> shows you
|
|
the history number assigned to a value by printing <SAMP>`$<VAR>n</VAR> = '</SAMP>
|
|
before the value; here <VAR>n</VAR> is the history number.
|
|
</P><P>
|
|
|
|
To refer to any previous value, use <SAMP>`$'</SAMP> followed by the value's
|
|
history number. The output printed by <SAMP>`print'</SAMP> is designed to remind
|
|
you of this. Just <SAMP>`$'</SAMP> refers to the most recent value in the history,
|
|
and <SAMP>`$$'</SAMP> refers to the value before that.
|
|
</P><P>
|
|
|
|
For example, suppose you have just printed a pointer to a structure and
|
|
want to see the contents of the structure. It suffices to type
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>p *$
|
|
</pre></td></tr></table></P><P>
|
|
|
|
If you have a chain of structures where the component <SAMP>`next'</SAMP> points
|
|
to the next one, you can print the contents of the next one with
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>p *$.next
|
|
</pre></td></tr></table></P><P>
|
|
|
|
It might be useful to repeat this command many times by typing <KBD>RET</KBD>.
|
|
</P><P>
|
|
|
|
Note that the history records values, not expressions. If the value of
|
|
<CODE>x</CODE> is 4 and you type
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>print x
|
|
set x=5
|
|
</pre></td></tr></table></P><P>
|
|
|
|
then the value recorded in the value history by the <SAMP>`print'</SAMP> command
|
|
remains 4 even though <CODE>x</CODE>'s value has changed.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>info history</CODE>
|
|
<DD><A NAME="IDX107"></A>
|
|
Print the last ten values in the value history, with their item
|
|
numbers. This is like <SAMP>`p $$9'</SAMP> repeated ten times, except that
|
|
<SAMP>`info history'</SAMP> does not change the history.
|
|
<P>
|
|
|
|
<DT><CODE>info history <VAR>n</VAR></CODE>
|
|
<DD>Print ten history values centered on history item number <VAR>n</VAR>.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Convenience Vars"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC48"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC47"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC49"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.7 Convenience Variables </H2>
|
|
<!--docid::SEC48::-->
|
|
<P>
|
|
|
|
<A NAME="IDX108"></A>
|
|
GDB provides <EM>convenience variables</EM> that you can use within GDB to
|
|
hold on to a value and refer to it later. These variables exist entirely
|
|
within GDB; they are not part of your program, and setting a convenience
|
|
variable has no effect on further execution of your program. That's why
|
|
you can use them freely.
|
|
</P><P>
|
|
|
|
Convenience variables have names starting with <SAMP>`$'</SAMP>. Any name starting
|
|
with <SAMP>`$'</SAMP> can be used for a convenience variable, unless it is one of
|
|
the predefined set of register names (see section <A HREF="gdb.html#SEC49">9.8 Registers</A>).
|
|
</P><P>
|
|
|
|
You can save a value in a convenience variable with an assignment
|
|
expression, just as you would set a variable in your program. Example:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>set $foo = *object_ptr
|
|
</pre></td></tr></table></P><P>
|
|
|
|
would save in <SAMP>`$foo'</SAMP> the value contained in the object pointed to by
|
|
<CODE>object_ptr</CODE>.
|
|
</P><P>
|
|
|
|
Using a convenience variable for the first time creates it; but its value
|
|
is <CODE>void</CODE> until you assign a new value. You can alter the value with
|
|
another assignment at any time.
|
|
</P><P>
|
|
|
|
Convenience variables have no fixed types. You can assign a convenience
|
|
variable any type of value, even if it already has a value of a different
|
|
type. The convenience variable as an expression has whatever type its
|
|
current value has.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>info convenience</CODE>
|
|
<DD><A NAME="IDX109"></A>
|
|
Print a list of convenience variables used so far, and their values.
|
|
Abbreviated <SAMP>`i con'</SAMP>.
|
|
</DL>
|
|
<P>
|
|
|
|
One of the ways to use a convenience variable is as a counter to be
|
|
incremented or a pointer to be advanced. For example:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>set $i = 0
|
|
print bar[$i++]->contents
|
|
<I><small>...</small>repeat that command by typing <KBD>RET</KBD>.</I>
|
|
</pre></td></tr></table></P><P>
|
|
|
|
Some convenience variables are created automatically by GDB and given
|
|
values likely to be useful.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><SAMP>`$_'</SAMP>
|
|
<DD>The variable <SAMP>`$_'</SAMP> is automatically set by the <SAMP>`x'</SAMP> command to
|
|
the last address examined (see section <A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A>). Other commands which
|
|
provide a default address for <SAMP>`x'</SAMP> to examine also set <SAMP>`$_'</SAMP>
|
|
to that address; these commands include <SAMP>`info line'</SAMP> and <SAMP>`info
|
|
breakpoint'</SAMP>.
|
|
<P>
|
|
|
|
<DT><SAMP>`$__'</SAMP>
|
|
<DD>The variable <SAMP>`$__'</SAMP> is automatically set by the <SAMP>`x'</SAMP> command
|
|
to the value found in the last address examined.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Registers"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC49"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC48"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC50"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 9.8 Registers </H2>
|
|
<!--docid::SEC49::-->
|
|
<P>
|
|
|
|
<A NAME="IDX110"></A>
|
|
Machine register contents can be referred to in expressions as variables
|
|
with names starting with <SAMP>`$'</SAMP>. The names of registers are different
|
|
for each machine; use <SAMP>`info registers'</SAMP> to see the names used on your
|
|
machine. The names <SAMP>`$pc'</SAMP> and <SAMP>`$sp'</SAMP> are used on all machines for
|
|
the program counter register and the stack pointer. Often <SAMP>`$fp'</SAMP> is
|
|
used for a register that contains a pointer to the current stack frame.
|
|
</P><P>
|
|
|
|
GDB always considers the contents of an ordinary register as an integer
|
|
when the register is examined in this way. Some machines have special
|
|
registers which can hold nothing but floating point; these registers are
|
|
considered floating point. There is no way to refer to the contents of an
|
|
ordinary register as floating point value (although you can <EM>print</EM>
|
|
it as a floating point value with <SAMP>`print/f $<VAR>regname</VAR>'</SAMP>).
|
|
</P><P>
|
|
|
|
Some registers have distinct "raw" and "virtual" data formats. This
|
|
means that the data format in which the register contents are saved by the
|
|
operating system is not the same one that your program normally sees. For
|
|
example, the registers of the 68881 floating point coprocessor are always
|
|
saved in "extended" format, but virtually all C programs expect to work with
|
|
"double" format. In such cases, GDB normally works with the virtual
|
|
format only (the format that makes sense for your program), but the
|
|
<SAMP>`info registers'</SAMP> command prints the data in both formats.
|
|
</P><P>
|
|
|
|
Register values are relative to the selected stack frame
|
|
(see section <A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A>). This means that you get the value that the register
|
|
would contain if all stack frames farther in were exited and their saved
|
|
registers restored. In order to see the real contents of all registers,
|
|
you must select the innermost frame (with <SAMP>`frame 0'</SAMP>).
|
|
</P><P>
|
|
|
|
Some registers are never saved (typically those numbered zero or one)
|
|
because they are used for returning function values; for these registers,
|
|
relativization makes no difference.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>info registers</CODE>
|
|
<DD><A NAME="IDX111"></A>
|
|
Print the names and relativized values of all registers.
|
|
<P>
|
|
|
|
<DT><CODE>info registers <VAR>regname</VAR></CODE>
|
|
<DD>Print the relativized value of register <VAR>regname</VAR>. <VAR>regname</VAR>
|
|
may be any register name valid on the machine you are using, with
|
|
or without the initial <SAMP>`$'</SAMP>.
|
|
</DL>
|
|
<P>
|
|
|
|
<HR SIZE="6">
|
|
<A NAME="SEC50"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC49"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H3> 9.8.1 Examples </H3>
|
|
<!--docid::SEC50::-->
|
|
<P>
|
|
|
|
You could print the program counter in hex with
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>p/x $pc
|
|
</pre></td></tr></table></P><P>
|
|
|
|
or print the instruction to be executed next with
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>x/i $pc
|
|
</pre></td></tr></table></P><P>
|
|
|
|
or add four to the stack pointer with
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>set $sp += 4
|
|
</pre></td></tr></table></P><P>
|
|
|
|
The last is a way of removing one word from the stack, on machines where
|
|
stacks grow downward in memory (most machines, nowadays). This assumes
|
|
that the innermost stack frame is selected. Setting <SAMP>`$sp'</SAMP> is
|
|
not allowed when other stack frames are selected.
|
|
</P><P>
|
|
|
|
<A NAME="Symbols"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC51"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC50"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC40"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 10. Examining the Symbol Table </H1>
|
|
<!--docid::SEC51::-->
|
|
<P>
|
|
|
|
The commands described in this section allow you to make inquiries for
|
|
information about the symbols (names of variables, functions and types)
|
|
defined in your program. This information is found by GDB in the symbol
|
|
table loaded by the <SAMP>`symbol-file'</SAMP> command; it is inherent in the text
|
|
of your program and does not change as the program executes.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>whatis <VAR>exp</VAR></CODE>
|
|
<DD><A NAME="IDX112"></A>
|
|
Print the data type of expression <VAR>exp</VAR>. <VAR>exp</VAR> is not
|
|
actually evaluated, and any side-effecting operations (such as
|
|
assignments or function calls) inside it do not take place.
|
|
See section <A HREF="gdb.html#SEC41">9.1 Expressions</A>.
|
|
<P>
|
|
|
|
<DT><CODE>whatis</CODE>
|
|
<DD>Print the data type of <SAMP>`$'</SAMP>, the last value in the value history.
|
|
<P>
|
|
|
|
<DT><CODE>info address <VAR>symbol</VAR></CODE>
|
|
<DD><A NAME="IDX113"></A>
|
|
Describe where the data for <VAR>symbol</VAR> is stored. For register
|
|
variables, this says which register. For other automatic variables,
|
|
this prints the stack-frame offset at which the variable is always
|
|
stored. Note the contrast with <SAMP>`print &<VAR>symbol</VAR>'</SAMP>, which does
|
|
not work at all for register variables and for automatic variables
|
|
prints the exact address of the current instantiation of the variable.
|
|
<P>
|
|
|
|
<DT><CODE>ptype <VAR>typename</VAR></CODE>
|
|
<DD><A NAME="IDX114"></A>
|
|
Print a description of data type <VAR>typename</VAR>. <VAR>typename</VAR> may be
|
|
the name of a type, or for C code it may have the form
|
|
<SAMP>`struct <VAR>struct-tag</VAR>'</SAMP>, <SAMP>`union <VAR>union-tag</VAR>'</SAMP> or
|
|
<SAMP>`enum <VAR>enum-tag</VAR>'</SAMP>.<P>
|
|
|
|
<DT><CODE>info sources</CODE>
|
|
<DD><A NAME="IDX115"></A>
|
|
Print the names of all source files in the program for which there
|
|
is debugging information.
|
|
<P>
|
|
|
|
<DT><CODE>info functions</CODE>
|
|
<DD><A NAME="IDX116"></A>
|
|
Print the names and data types of all defined functions.
|
|
<P>
|
|
|
|
<DT><CODE>info functions <VAR>regexp</VAR></CODE>
|
|
<DD>Print the names and data types of all defined functions
|
|
whose names contain a match for regular expression <VAR>regexp</VAR>.
|
|
Thus, <SAMP>`info fun step'</SAMP> finds all functions whose names
|
|
include <SAMP>`step'</SAMP>; <SAMP>`info fun ^step'</SAMP> finds those whose names
|
|
start with <SAMP>`step'</SAMP>.
|
|
<P>
|
|
|
|
<DT><CODE>info variables</CODE>
|
|
<DD><A NAME="IDX117"></A>
|
|
Print the names and data types of all variables that are declared
|
|
outside of functions.
|
|
<P>
|
|
|
|
<DT><CODE>info variables <VAR>regexp</VAR></CODE>
|
|
<DD>Print the names and data types of all variables, declared outside of
|
|
functions, whose names contain a match for regular expression
|
|
<VAR>regexp</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>info types</CODE>
|
|
<DD><A NAME="IDX118"></A>
|
|
Print all data types that are defined in the program.
|
|
<P>
|
|
|
|
<DT><CODE>info types <VAR>regexp</VAR></CODE>
|
|
<DD>Print all data types that are defined in the program whose names
|
|
contain a match for regular expression <VAR>regexp</VAR>.
|
|
<P>
|
|
|
|
<DT><CODE>info methods</CODE>
|
|
<DD><DT><CODE>info methods <VAR>regexp</VAR></CODE>
|
|
<DD><A NAME="IDX119"></A>
|
|
The <SAMP>`info-methods'</SAMP> command permits the user to examine all defined
|
|
methods within C<CODE>++</CODE> program, or (with the <VAR>regexp</VAR> argument) a
|
|
specific set of methods found in the various C<CODE>++</CODE> classes. Many
|
|
C<CODE>++</CODE> classes which implement a large number of differently typed
|
|
methods implement a large number of methods as well. Thus, the
|
|
<SAMP>`ptype'</SAMP> command can give the user a tremendous overdose of
|
|
information about what methods are associated with a given class. The
|
|
<SAMP>`info-methods'</SAMP> command filters these methods do to only those
|
|
methods which match the regular-expression search key.
|
|
<P>
|
|
|
|
<DT><CODE>printsyms <VAR>filename</VAR></CODE>
|
|
<DD><A NAME="IDX120"></A>
|
|
Write a complete dump of the debugger's symbol data into the
|
|
file <VAR>filename</VAR>.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Altering"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC52"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC53"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC51"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 11. Altering Execution </H1>
|
|
<!--docid::SEC52::-->
|
|
<P>
|
|
|
|
There are several ways to alter the execution of your program with GDB
|
|
commands.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC53">11.1 Assignment to Variables</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Altering variable values or memory contents.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC54">11.2 Continuing at a Different Address</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Altering control flow.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC55">11.3 Giving the Program a Signal</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Making signals happen in the program.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC56">11.4 Returning from a Function</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Making a function return prematurely.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Assignment"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC53"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC54"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 11.1 Assignment to Variables </H2>
|
|
<!--docid::SEC53::-->
|
|
<P>
|
|
|
|
<A NAME="IDX121"></A>
|
|
<A NAME="IDX122"></A>
|
|
To alter the value of a variable, evaluate an assignment expression.
|
|
See section <A HREF="gdb.html#SEC41">9.1 Expressions</A>. For example,
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>print x=4
|
|
</pre></td></tr></table></P><P>
|
|
|
|
would store the value 4 into the variable <CODE>x</CODE>, and then print
|
|
the value of the assignment expression (which is 4).
|
|
</P><P>
|
|
|
|
<A NAME="IDX123"></A>
|
|
<A NAME="IDX124"></A>
|
|
If you are not interested in seeing the value of the assignment, use the
|
|
<SAMP>`set'</SAMP> command instead of the <SAMP>`print'</SAMP> command. <SAMP>`set'</SAMP> is
|
|
really the same as <SAMP>`print'</SAMP> except that the expression's value is not
|
|
printed and is not put in the value history (see section <A HREF="gdb.html#SEC47">9.6 Value History</A>). The
|
|
expression is evaluated only for side effects.
|
|
</P><P>
|
|
|
|
Note that if the beginning of the argument string of the <SAMP>`set'</SAMP> command
|
|
appears identical to a <SAMP>`set'</SAMP> subcommand, it may be necessary to use
|
|
the <SAMP>`set variable'</SAMP> command. This command is identical to <SAMP>`set'</SAMP>
|
|
except for its lack of subcommands.
|
|
</P><P>
|
|
|
|
GDB allows more implicit conversions in assignments than C does; you can
|
|
freely store an integer value into a pointer variable or vice versa, and
|
|
any structure can be converted to any other structure that is the same
|
|
length or shorter.
|
|
</P><P>
|
|
|
|
In C, all the other assignment operators such as <SAMP>`+='</SAMP> and <SAMP>`++'</SAMP>
|
|
are supported as well.
|
|
</P><P>
|
|
|
|
To store into arbitrary places in memory, use the <SAMP>`{<small>...</small>}'</SAMP>
|
|
construct to generate a value of specified type at a specified address
|
|
(see section <A HREF="gdb.html#SEC41">9.1 Expressions</A>). For example,
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>set {int}0x83040 = 4
|
|
</pre></td></tr></table></P><P>
|
|
|
|
<A NAME="Jumping"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC54"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC53"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC55"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 11.2 Continuing at a Different Address </H2>
|
|
<!--docid::SEC54::-->
|
|
<P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>jump <VAR>linenum</VAR></CODE>
|
|
<DD><A NAME="IDX125"></A>
|
|
Resume execution at line number <VAR>linenum</VAR>. Execution may stop
|
|
immediately if there is a breakpoint there.
|
|
<P>
|
|
|
|
The <SAMP>`jump'</SAMP> command does not change the current stack frame, or
|
|
the stack pointer, or the contents of any memory location or any
|
|
register other than the program counter. If line <VAR>linenum</VAR> is in
|
|
a different function from the one currently executing, the results may
|
|
be wild if the two functions expect different patterns of arguments or
|
|
of local variables. For this reason, the <SAMP>`jump'</SAMP> command requests
|
|
confirmation if the specified line is not in the function currently
|
|
executing. However, even wild results are predictable based on
|
|
changing the program counter.
|
|
</P><P>
|
|
|
|
<DT><CODE>jump *<VAR>address</VAR></CODE>
|
|
<DD>Resume execution at the instruction at address <VAR>address</VAR>.
|
|
</DL>
|
|
<P>
|
|
|
|
A similar effect can be obtained by storing a new value into the register
|
|
<SAMP>`$pc'</SAMP>, but not exactly the same.
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>set $pc = 0x485
|
|
</pre></td></tr></table></P><P>
|
|
|
|
specifies the address at which execution will resume, but does not resume
|
|
execution. That does not happen until you use the <SAMP>`cont'</SAMP> command or a
|
|
stepping command (see section <A HREF="gdb.html#SEC30">6.4 Stepping</A>).
|
|
</P><P>
|
|
|
|
<A NAME="Signaling"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC55"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC54"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC56"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 11.3 Giving the Program a Signal </H2>
|
|
<!--docid::SEC55::-->
|
|
<P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>signal <VAR>signalnum</VAR></CODE>
|
|
<DD><A NAME="IDX126"></A>
|
|
Resume execution where the program stopped, but give it immediately
|
|
the signal number <VAR>signalnum</VAR>.
|
|
<P>
|
|
|
|
Alternatively, if <VAR>signalnum</VAR> is zero, continue execution and give
|
|
no signal. This is useful when the program has received a signal
|
|
but you don't want the program to see that signal; the <SAMP>`cont'</SAMP> command
|
|
would signal the program.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Returning"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC56"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC55"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 11.4 Returning from a Function </H2>
|
|
<!--docid::SEC56::-->
|
|
<P>
|
|
|
|
<A NAME="IDX127"></A>
|
|
<A NAME="IDX128"></A>
|
|
You can make any function call return immediately, using the <SAMP>`return'</SAMP>
|
|
command.
|
|
</P><P>
|
|
|
|
First select the stack frame that you wish to return from
|
|
(see section <A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A>). Then type the <SAMP>`return'</SAMP> command. If you wish to
|
|
specify the value to be returned, give that as an argument.
|
|
</P><P>
|
|
|
|
This pops the selected stack frame (and any other frames inside of it),
|
|
leaving its caller as the innermost remaining frame. That frame becomes
|
|
selected. The specified value is stored in the registers used for
|
|
returning values of functions.
|
|
</P><P>
|
|
|
|
The <SAMP>`return'</SAMP> command does not resume execution; it leaves the program
|
|
stopped in the state that would exist if the function had just returned.
|
|
Contrast this with the <SAMP>`finish'</SAMP> command (see section <A HREF="gdb.html#SEC30">6.4 Stepping</A>), which
|
|
resumes execution <I>until</I> the selected stack frame returns naturally.
|
|
</P><P>
|
|
|
|
<A NAME="Sequences"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC57"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC56"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC58"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC52"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC61"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 12. Canned Sequences of Commands </H1>
|
|
<!--docid::SEC57::-->
|
|
<P>
|
|
|
|
GDB provides two ways to store sequences of commands for execution as a
|
|
unit: user-defined commands and command files.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC58">12.1 User-Defined Commands</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">User-defined commands.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC59">12.2 Command Files</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Command files.</TD></TR>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC60">12.3 Commands for Controlled Output</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Controlled output commands useful in
|
|
user-defined commands and command files.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
<A NAME="Define"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC58"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC59"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC61"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 12.1 User-Defined Commands </H2>
|
|
<!--docid::SEC58::-->
|
|
<P>
|
|
|
|
<A NAME="IDX129"></A>
|
|
A <EM>user-defined command</EM> is a sequence of GDB commands to which you
|
|
assign a new name as a command. This is done with the <SAMP>`define'</SAMP>
|
|
command.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>define <VAR>commandname</VAR></CODE>
|
|
<DD><A NAME="IDX130"></A>
|
|
Define a command named <VAR>commandname</VAR>. If there is already a command
|
|
by that name, you are asked to confirm that you want to redefine it.
|
|
<P>
|
|
|
|
The definition of the command is made up of other GDB command lines,
|
|
which are given following the <SAMP>`define'</SAMP> command. The end of these
|
|
commands is marked by a line containing <SAMP>`end'</SAMP>.
|
|
</P><P>
|
|
|
|
<DT><CODE>document <VAR>commandname</VAR></CODE>
|
|
<DD><A NAME="IDX131"></A>
|
|
Give documentation to the user-defined command <VAR>commandname</VAR>. The
|
|
command <VAR>commandname</VAR> must already be defined. This command reads
|
|
lines of documentation just as <SAMP>`define'</SAMP> reads the lines of the
|
|
command definition, ending with <SAMP>`end'</SAMP>. After the <SAMP>`document'</SAMP> command is finished,
|
|
<SAMP>`help'</SAMP> on command <VAR>commandname</VAR> will print the documentation
|
|
you have specified.
|
|
<P>
|
|
|
|
You may use the <SAMP>`document'</SAMP> command again to change the
|
|
documentation of a command. Redefining the command with <SAMP>`define'</SAMP>
|
|
does not change the documentation.
|
|
</DL>
|
|
<P>
|
|
|
|
User-defined commands do not take arguments. When they are executed, the
|
|
commands of the definition are not printed. An error in any command
|
|
stops execution of the user-defined command.
|
|
</P><P>
|
|
|
|
Commands that would ask for confirmation if used interactively proceed
|
|
without asking when used inside a user-defined command. Many GDB commands
|
|
that normally print messages to say what they are doing omit the messages
|
|
when used in user-defined command.
|
|
</P><P>
|
|
|
|
<A NAME="Command Files"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC59"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC58"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC60"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC61"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 12.2 Command Files </H2>
|
|
<!--docid::SEC59::-->
|
|
<P>
|
|
|
|
<A NAME="IDX132"></A>
|
|
A command file for GDB is a file of lines that are GDB commands. Comments
|
|
(lines starting with <SAMP>`#'</SAMP>) may also be included. An empty line in a
|
|
command file does nothing; it does not mean to repeat the last command, as
|
|
it would from the terminal.
|
|
</P><P>
|
|
|
|
<A NAME="IDX133"></A>
|
|
<A NAME="IDX134"></A>
|
|
When GDB starts, it automatically executes its <EM>init files</EM>, command
|
|
files named <TT>`.gdbinit'</TT>. GDB reads the init file (if any) in your home
|
|
directory and then the init file (if any) in the current working
|
|
directory. (The init files are not executed if the <SAMP>`-nx'</SAMP> option
|
|
is given.) You can also request the execution of a command file with the
|
|
<SAMP>`source'</SAMP> command:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>source <VAR>filename</VAR></CODE>
|
|
<DD><A NAME="IDX135"></A>
|
|
Execute the command file <VAR>filename</VAR>.
|
|
</DL>
|
|
<P>
|
|
|
|
The lines in a command file are executed sequentially. They are not
|
|
printed as they are executed. An error in any command terminates execution
|
|
of the command file.
|
|
</P><P>
|
|
|
|
Commands that would ask for confirmation if used interactively proceed
|
|
without asking when used in a command file. Many GDB commands that
|
|
normally print messages to say what they are doing omit the messages
|
|
when used in a command file.
|
|
</P><P>
|
|
|
|
<A NAME="Output"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC60"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC59"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC61"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC61"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 12.3 Commands for Controlled Output </H2>
|
|
<!--docid::SEC60::-->
|
|
<P>
|
|
|
|
During the execution of a command file or a user-defined command, the only
|
|
output that appears is what is explicitly printed by the commands of the
|
|
definition. This section describes three commands useful for generating
|
|
exactly the output you want.
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><CODE>echo <VAR>text</VAR></CODE>
|
|
<DD><A NAME="IDX136"></A>
|
|
Print <VAR>text</VAR>. Nonprinting characters can be included in
|
|
<VAR>text</VAR> using C escape sequences, such as <SAMP>`\n'</SAMP> to print a
|
|
newline. <B>No newline will be printed unless you specify one.</B>
|
|
<P>
|
|
|
|
A backslash at the end of <VAR>text</VAR> is ignored. It is useful for
|
|
outputting a string ending in spaces, since trailing spaces are
|
|
trimmed from all arguments. A backslash at the beginning preserves
|
|
leading spaces in the same way, because <SAMP>`\ '</SAMP> as an escape
|
|
sequence stands for a space. Thus, to print <SAMP>` and foo = '</SAMP>, do
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>echo \ and foo = \
|
|
</pre></td></tr></table></P><P>
|
|
|
|
<DT><CODE>output <VAR>expression</VAR></CODE>
|
|
<DD><A NAME="IDX137"></A>
|
|
Print the value of <VAR>expression</VAR> and nothing but that value: no
|
|
newlines, no <SAMP>`$<VAR>nn</VAR> = '</SAMP>. The value is not entered in the
|
|
value history either. See section <A HREF="gdb.html#SEC41">9.1 Expressions</A> for more information
|
|
on expressions.
|
|
<P>
|
|
|
|
<DT><CODE>output/<VAR>fmt</VAR> <VAR>expression</VAR></CODE>
|
|
<DD>Print the value of <VAR>expression</VAR> in format <VAR>fmt</VAR>.
|
|
See section <A HREF="gdb.html#SEC44">9.4 Formats</A>, for more information.
|
|
<P>
|
|
|
|
<DT><CODE>printf <VAR>string</VAR>, <VAR>expressions</VAR><small>...</small></CODE>
|
|
<DD><A NAME="IDX138"></A>
|
|
Print the values of the <VAR>expressions</VAR> under the control of
|
|
<VAR>string</VAR>. The <VAR>expressions</VAR> are separated by commas and may
|
|
be either numbers or pointers. Their values are printed as specified
|
|
by <VAR>string</VAR>, exactly as if the program were to execute
|
|
<P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>printf (<VAR>string</VAR>, <VAR>expressions</VAR><small>...</small>);
|
|
</pre></td></tr></table></P><P>
|
|
|
|
For example, you can print two values in hex like this:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>printf "foo, bar-foo = 0x%x, 0x%x\n", foo, bar-foo
|
|
</pre></td></tr></table></P><P>
|
|
|
|
The only backslash-escape sequences that you can use in the string are
|
|
the simple ones that consist of backslash followed by a letter.
|
|
</DL>
|
|
<P>
|
|
|
|
<A NAME="Emacs"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC61"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC60"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC62"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC57"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC62"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 13. Using GDB under GNU Emacs </H1>
|
|
<!--docid::SEC61::-->
|
|
<P>
|
|
|
|
A special interface allows you to use GNU Emacs to view (and
|
|
edit) the source files for the program you are debugging with
|
|
GDB.
|
|
</P><P>
|
|
|
|
To use this interface, use the command <KBD>M-x gdb</KBD> in Emacs.
|
|
Give the executable file you want to debug as an argument. This
|
|
command starts a GDB process as a subprocess of Emacs, with input
|
|
and output through a newly created Emacs buffer.
|
|
</P><P>
|
|
|
|
Using this GDB process is just like using GDB normally except for two things:
|
|
</P><P>
|
|
|
|
<UL>
|
|
<LI>
|
|
All "terminal" input and output goes through the Emacs buffer. This
|
|
applies both to GDB commands and their output, and to the input and
|
|
output done by the program you are debugging.
|
|
<P>
|
|
|
|
This is useful because it means that you can copy the text of previous
|
|
commands and input them again; you can even use parts of the output
|
|
in this way.
|
|
</P><P>
|
|
|
|
All the facilities of Emacs's Shell mode are available for this purpose.
|
|
</P><P>
|
|
|
|
<LI>
|
|
GDB displays source code through Emacs. Each time GDB displays a
|
|
stack frame, Emacs automatically finds the source file for that frame
|
|
and puts an arrow (<SAMP>`=>'</SAMP>) at the left margin of the current line.
|
|
<P>
|
|
|
|
Explicit GDB <SAMP>`list'</SAMP> or search commands still produce output as
|
|
usual, but you probably will have no reason to use them.
|
|
</UL>
|
|
<P>
|
|
|
|
In the GDB I/O buffer, you can use these special Emacs commands:
|
|
</P><P>
|
|
|
|
<DL COMPACT>
|
|
<DT><KBD>M-s</KBD>
|
|
<DD>Execute to another source line, like the GDB <SAMP>`step'</SAMP> command.
|
|
<P>
|
|
|
|
<DT><KBD>M-n</KBD>
|
|
<DD>Execute to next source line in this function, skipping all function
|
|
calls, like the GDB <SAMP>`next'</SAMP> command.
|
|
<P>
|
|
|
|
<DT><KBD>M-i</KBD>
|
|
<DD>Execute one instruction, like the GDB <SAMP>`stepi'</SAMP> command.
|
|
<P>
|
|
|
|
<DT><KBD>M-u</KBD>
|
|
<DD>Move up one stack frame (and display that frame's source file in
|
|
Emacs), like the GDB <SAMP>`up'</SAMP> command.
|
|
<P>
|
|
|
|
<DT><KBD>M-d</KBD>
|
|
<DD>Move down one stack frame (and display that frame's source file in
|
|
Emacs), like the GDB <SAMP>`down'</SAMP> command. (This means that you cannot
|
|
delete words in the usual fashion in the GDB buffer; I am guessing you
|
|
won't often want to do that.)
|
|
<P>
|
|
|
|
<DT><KBD>C-c C-f</KBD>
|
|
<DD>Execute until exit from the selected stack frame, like the GDB
|
|
<SAMP>`finish'</SAMP> command.
|
|
</DL>
|
|
<P>
|
|
|
|
In any source file, the Emacs command <KBD>C-x SPC</KBD> (<CODE>gdb-break</CODE>)
|
|
tells GDB to set a breakpoint on the source line point is on.
|
|
</P><P>
|
|
|
|
The source files displayed in Emacs are in ordinary Emacs buffers
|
|
which are visiting the source files in the usual way. You can edit
|
|
the files with these buffers if you wish; but keep in mind that GDB
|
|
communicates with Emacs in terms of line numbers. If you add or
|
|
delete lines from the text, the line numbers that GDB knows will cease
|
|
to correspond properly to the code.
|
|
</P><P>
|
|
|
|
<A NAME="Remote"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC62"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC61"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC63"> > </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC61"> << </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC64"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> 14. Remote Kernel Debugging </H1>
|
|
<!--docid::SEC62::-->
|
|
<P>
|
|
|
|
GDB has a special facility for debugging a remote machine via a serial
|
|
connection. This can be used for kernel debugging.
|
|
</P><P>
|
|
|
|
The program to be debugged on the remote machine needs to contain a
|
|
debugging device driver which talks to GDB over the serial line using the
|
|
protocol described below. The same version of GDB that is used ordinarily
|
|
can be used for this.
|
|
</P><P>
|
|
|
|
<BLOCKQUOTE><TABLE BORDER=0 CELLSPACING=0>
|
|
<TR><TD ALIGN="left" VALIGN="TOP"><A HREF="gdb.html#SEC63">14.1 Commands for Remote Debugging</A></TD><TD> </TD><TD ALIGN="left" VALIGN="TOP">Commands used to start and finish remote debugging.</TD></TR>
|
|
</TABLE></BLOCKQUOTE>
|
|
<P>
|
|
|
|
For details of the communication protocol, see the comments in the GDB
|
|
source file <TT>`remote.c'</TT>.
|
|
</P><P>
|
|
|
|
<A NAME="Remote Commands"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC63"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC62"> < </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC64"> > </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC62"> << </A>]</TD>
|
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|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC64"> >> </A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H2> 14.1 Commands for Remote Debugging </H2>
|
|
<!--docid::SEC63::-->
|
|
<P>
|
|
|
|
To start remote debugging, first run GDB and specify as an executable file
|
|
the program that is running in the remote machine. This tells GDB how
|
|
to find the program's symbols and the contents of its pure text. Then
|
|
establish communication using the <SAMP>`attach'</SAMP> command with a device
|
|
name rather than a pid as an argument. For example:
|
|
</P><P>
|
|
|
|
<TABLE><tr><td> </td><td class=example><pre>attach /dev/ttyd
|
|
</pre></td></tr></table></P><P>
|
|
|
|
if the serial line is connected to the device named <TT>`/dev/ttyd'</TT>. This
|
|
will stop the remote machine if it is not already stopped.
|
|
</P><P>
|
|
|
|
Now you can use all the usual commands to examine and change data and to
|
|
step and continue the remote program.
|
|
</P><P>
|
|
|
|
To resume the remote program and stop debugging it, use the <SAMP>`detach'</SAMP>
|
|
command.
|
|
</P><P>
|
|
|
|
<A NAME="Commands"></A>
|
|
<HR SIZE="6">
|
|
<A NAME="SEC64"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC63"> < </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC65"> > </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC62"> << </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC65"> >> </A>]</TD>
|
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1> Command Index </H1>
|
|
<!--docid::SEC64::-->
|
|
<P>
|
|
|
|
<table><tr><th valign=top>Jump to: </th><td><A HREF="gdb.html#ky_!" style="text-decoration:none"><b>!</b></A>
|
|
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<A HREF="gdb.html#ky_$" style="text-decoration:none"><b>$</b></A>
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<BR>
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<A HREF="gdb.html#ky_A" style="text-decoration:none"><b>A</b></A>
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<A HREF="gdb.html#ky_B" style="text-decoration:none"><b>B</b></A>
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<A HREF="gdb.html#ky_C" style="text-decoration:none"><b>C</b></A>
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<A HREF="gdb.html#ky_D" style="text-decoration:none"><b>D</b></A>
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<A HREF="gdb.html#ky_E" style="text-decoration:none"><b>E</b></A>
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<A HREF="gdb.html#ky_F" style="text-decoration:none"><b>F</b></A>
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<A HREF="gdb.html#ky_H" style="text-decoration:none"><b>H</b></A>
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<A HREF="gdb.html#ky_I" style="text-decoration:none"><b>I</b></A>
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<A HREF="gdb.html#ky_J" style="text-decoration:none"><b>J</b></A>
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<A HREF="gdb.html#ky_K" style="text-decoration:none"><b>K</b></A>
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<A HREF="gdb.html#ky_L" style="text-decoration:none"><b>L</b></A>
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<A HREF="gdb.html#ky_N" style="text-decoration:none"><b>N</b></A>
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<A HREF="gdb.html#ky_O" style="text-decoration:none"><b>O</b></A>
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<A HREF="gdb.html#ky_P" style="text-decoration:none"><b>P</b></A>
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<A HREF="gdb.html#ky_Q" style="text-decoration:none"><b>Q</b></A>
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<A HREF="gdb.html#ky_R" style="text-decoration:none"><b>R</b></A>
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<A HREF="gdb.html#ky_S" style="text-decoration:none"><b>S</b></A>
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<A HREF="gdb.html#ky_T" style="text-decoration:none"><b>T</b></A>
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<A HREF="gdb.html#ky_U" style="text-decoration:none"><b>U</b></A>
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<A HREF="gdb.html#ky_W" style="text-decoration:none"><b>W</b></A>
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<A HREF="gdb.html#ky_X" style="text-decoration:none"><b>X</b></A>
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</td></tr></table><br><P></P>
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<TABLE border=0>
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<TR><TD></TD><TH ALIGN=LEFT>Index Entry</TH><TH ALIGN=LEFT> Section</TH></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_!"></A>!</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX2"><CODE>!</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC5">1. GDB Input Conventions</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_$"></A>$</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX35"><CODE>$_</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC22">6.2 Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX80"><CODE>$_</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC37">8.1 Printing Source Lines</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX96"><CODE>$_</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX97"><CODE>$__</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_A"></A>A</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX13"><CODE>add-file</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#SEC19"><CODE>attach</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC19">5.5 Debugging an Already-Running Process</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_B"></A>B</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX36"><CODE>break</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC23">6.2.1 Setting Breakpoints</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_C"></A>C</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX26"><CODE>cd</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC17">5.3 Your Program's Working Directory</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX40"><CODE>clear</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC24">6.2.2 Clearing Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX49"><CODE>condition</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX54"><CODE>cont</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC29">6.3 Continuing</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX12"><CODE>core-file</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_D"></A>D</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX130"><CODE>define</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC58">12.1 User-Defined Commands</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX41"><CODE>delete</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC24">6.2.2 Clearing Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX100"><CODE>delete display</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC46">9.5 Automatic Display</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX23"><CODE>delete environment</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC16">5.2 Your Program's Environment</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#SEC19"><CODE>detach</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC19">5.5 Debugging an Already-Running Process</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX83"><CODE>directory</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC39">8.3 Specifying Source Directories</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX45"><CODE>disable</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX44"><CODE>disable breakpoints</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX101"><CODE>disable display</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC46">9.5 Automatic Display</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX98"><CODE>display</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC46">9.5 Automatic Display</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX131"><CODE>document</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC58">12.1 User-Defined Commands</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX74"><CODE>down</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_E"></A>E</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX136"><CODE>echo</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC60">12.3 Commands for Controlled Output</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX47"><CODE>enable</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX46"><CODE>enable breakpoints</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX102"><CODE>enable display</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC46">9.5 Automatic Display</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX10"><CODE>exec-file</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
|
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<TR><TH><A NAME="ky_F"></A>F</TH><TD></TD><TD></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX58"><CODE>finish</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#SEC38"><CODE>forward-search</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC38">8.2 Searching Source Files</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX72"><CODE>frame</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
|
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<TR><TH><A NAME="ky_H"></A>H</TH><TD></TD><TD></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX32"><CODE>handle</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC21">6.1 Signals</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
|
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<TR><TH><A NAME="ky_I"></A>I</TH><TD></TD><TD></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX51"><CODE>ignore</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX113"><CODE>info address</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX76"><CODE>info args</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC35">7.4 Information on a Frame</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX34"><CODE>info break</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC22">6.2 Breakpoints</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX109"><CODE>info convenience</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC48">9.7 Convenience Variables</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX84"><CODE>info directories</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC39">8.3 Specifying Source Directories</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX103"><CODE>info display</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC46">9.5 Automatic Display</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX21"><CODE>info environment</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC16">5.2 Your Program's Environment</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX15"><CODE>info files</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX75"><CODE>info frame</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC35">7.4 Information on a Frame</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX116"><CODE>info functions</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX107"><CODE>info history</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC47">9.6 Value History</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX79"><CODE>info line</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC37">8.1 Printing Source Lines</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX77"><CODE>info locals</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC35">7.4 Information on a Frame</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX119"><CODE>info methods</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX111"><CODE>info registers</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC49">9.8 Registers</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX31"><CODE>info signal</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC21">6.1 Signals</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX115"><CODE>info sources</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX118"><CODE>info types</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX117"><CODE>info variables</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_J"></A>J</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX125"><CODE>jump</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC54">11.2 Continuing at a Different Address</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_K"></A>K</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX14"><CODE>kill</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_L"></A>L</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX78"><CODE>list</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC37">8.1 Printing Source Lines</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_N"></A>N</TH><TD></TD><TD></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX57"><CODE>next</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX62"><CODE>nexti</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX63"><CODE>ni</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_O"></A>O</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX137"><CODE>output</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC60">12.3 Commands for Controlled Output</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_P"></A>P</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX87"><CODE>print</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC40">9. Examining Data</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX138"><CODE>printf</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC60">12.3 Commands for Controlled Output</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX120"><CODE>printsyms</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX114"><CODE>ptype</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX27"><CODE>pwd</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC17">5.3 Your Program's Working Directory</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_Q"></A>Q</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX6"><CODE>quit</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC5">1. GDB Input Conventions</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_R"></A>R</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX128"><CODE>return</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC56">11.4 Returning from a Function</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#SEC38"><CODE>reverse-search</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC38">8.2 Searching Source Files</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX17"><CODE>run</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC14">5. Running Your Program Under GDB</A></TD></TR>
|
|
<TR><TD COLSPAN=3> <HR></TD></TR>
|
|
<TR><TH><A NAME="ky_S"></A>S</TH><TD></TD><TD></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX123"><CODE>set</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC53">11.1 Assignment to Variables</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX19"><CODE>set args</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC15">5.1 Your Program's Arguments</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX88"><CODE>set array-max</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC40">9. Examining Data</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX22"><CODE>set environment</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC16">5.2 Your Program's Environment</A></TD></TR>
|
|
<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX4"><CODE>set prompt</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC5">1. GDB Input Conventions</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX124"><CODE>set variable</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC53">11.1 Assignment to Variables</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX1"><CODE>shell</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC5">1. GDB Input Conventions</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX61"><CODE>si</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX126"><CODE>signal</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC55">11.3 Giving the Program a Signal</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX53"><CODE>silent</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC27">6.2.5 Commands Executed on Breaking</A></TD></TR>
|
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX135"><CODE>source</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC59">12.2 Command Files</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX56"><CODE>step</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX60"><CODE>stepi</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX11"><CODE>symbol-file</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_T"></A>T</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX37"><CODE>tbreak</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC23">6.2.1 Setting Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX30"><CODE>tty</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC18">5.4 Your Program's Input and Output</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_U"></A>U</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX99"><CODE>undisplay</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC46">9.5 Automatic Display</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX24"><CODE>unset environment</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC16">5.2 Your Program's Environment</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX59"><CODE>until</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX73"><CODE>up</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC34">7.3 Selecting a Frame</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_W"></A>W</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX112"><CODE>whatis</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC51">10. Examining the Symbol Table</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="ky_X"></A>X</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX94"><CODE>x</CODE></A></TD><TD valign=top><A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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</TABLE><P></P><table><tr><th valign=top>Jump to: </th><td><A HREF="gdb.html#ky_!" style="text-decoration:none"><b>!</b></A>
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<A HREF="gdb.html#ky_$" style="text-decoration:none"><b>$</b></A>
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<BR>
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<A HREF="gdb.html#ky_A" style="text-decoration:none"><b>A</b></A>
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<A HREF="gdb.html#ky_B" style="text-decoration:none"><b>B</b></A>
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<A HREF="gdb.html#ky_C" style="text-decoration:none"><b>C</b></A>
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<A HREF="gdb.html#ky_D" style="text-decoration:none"><b>D</b></A>
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<A HREF="gdb.html#ky_E" style="text-decoration:none"><b>E</b></A>
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<A HREF="gdb.html#ky_F" style="text-decoration:none"><b>F</b></A>
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<A HREF="gdb.html#ky_H" style="text-decoration:none"><b>H</b></A>
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<A HREF="gdb.html#ky_I" style="text-decoration:none"><b>I</b></A>
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<A HREF="gdb.html#ky_J" style="text-decoration:none"><b>J</b></A>
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<A HREF="gdb.html#ky_K" style="text-decoration:none"><b>K</b></A>
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<A HREF="gdb.html#ky_L" style="text-decoration:none"><b>L</b></A>
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<A HREF="gdb.html#ky_N" style="text-decoration:none"><b>N</b></A>
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<A HREF="gdb.html#ky_O" style="text-decoration:none"><b>O</b></A>
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<A HREF="gdb.html#ky_P" style="text-decoration:none"><b>P</b></A>
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<A HREF="gdb.html#ky_Q" style="text-decoration:none"><b>Q</b></A>
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<A HREF="gdb.html#ky_R" style="text-decoration:none"><b>R</b></A>
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<A HREF="gdb.html#ky_S" style="text-decoration:none"><b>S</b></A>
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<A HREF="gdb.html#ky_T" style="text-decoration:none"><b>T</b></A>
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<A HREF="gdb.html#ky_U" style="text-decoration:none"><b>U</b></A>
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<A HREF="gdb.html#ky_W" style="text-decoration:none"><b>W</b></A>
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<A HREF="gdb.html#ky_X" style="text-decoration:none"><b>X</b></A>
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</td></tr></table><br></P><P>
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<A NAME="Concepts"></A>
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<HR SIZE="6">
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<A NAME="SEC65"></A>
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<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
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<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC64"> < </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[ > ]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC64"> << </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top"> Up </A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[ >> ]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT"> <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
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<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
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</TR></TABLE>
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<H1> Concept Index </H1>
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<!--docid::SEC65::-->
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<P>
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<table><tr><th valign=top>Jump to: </th><td><A HREF="gdb.html#cp_$" style="text-decoration:none"><b>$</b></A>
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<A HREF="gdb.html#cp_." style="text-decoration:none"><b>.</b></A>
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<BR>
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<A HREF="gdb.html#cp_A" style="text-decoration:none"><b>A</b></A>
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<A HREF="gdb.html#cp_B" style="text-decoration:none"><b>B</b></A>
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<A HREF="gdb.html#cp_C" style="text-decoration:none"><b>C</b></A>
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<A HREF="gdb.html#cp_D" style="text-decoration:none"><b>D</b></A>
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<A HREF="gdb.html#cp_E" style="text-decoration:none"><b>E</b></A>
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<A HREF="gdb.html#cp_F" style="text-decoration:none"><b>F</b></A>
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<A HREF="gdb.html#cp_I" style="text-decoration:none"><b>I</b></A>
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<A HREF="gdb.html#cp_O" style="text-decoration:none"><b>O</b></A>
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<A HREF="gdb.html#cp_P" style="text-decoration:none"><b>P</b></A>
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<A HREF="gdb.html#cp_R" style="text-decoration:none"><b>R</b></A>
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<A HREF="gdb.html#cp_S" style="text-decoration:none"><b>S</b></A>
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<A HREF="gdb.html#cp_U" style="text-decoration:none"><b>U</b></A>
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<A HREF="gdb.html#cp_V" style="text-decoration:none"><b>V</b></A>
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<A HREF="gdb.html#cp_W" style="text-decoration:none"><b>W</b></A>
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</td></tr></table><br><P></P>
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<TABLE border=0>
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<TR><TD></TD><TH ALIGN=LEFT>Index Entry</TH><TH ALIGN=LEFT> Section</TH></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_$"></A>$</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX105">$</A></TD><TD valign=top><A HREF="gdb.html#SEC47">9.6 Value History</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX106">$$</A></TD><TD valign=top><A HREF="gdb.html#SEC47">9.6 Value History</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_."></A>.</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX134">.gdbinit</A></TD><TD valign=top><A HREF="gdb.html#SEC59">12.2 Command Files</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_A"></A>A</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX18">arguments (to your program)</A></TD><TD valign=top><A HREF="gdb.html#SEC15">5.1 Your Program's Arguments</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX90">artificial array</A></TD><TD valign=top><A HREF="gdb.html#SEC43">9.3 Artificial Arrays</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX121">assignment</A></TD><TD valign=top><A HREF="gdb.html#SEC53">11.1 Assignment to Variables</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#SEC19">attach</A></TD><TD valign=top><A HREF="gdb.html#SEC19">5.5 Debugging an Already-Running Process</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_B"></A>B</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX52">breakpoint commands</A></TD><TD valign=top><A HREF="gdb.html#SEC27">6.2.5 Commands Executed on Breaking</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX33">breakpoints</A></TD><TD valign=top><A HREF="gdb.html#SEC22">6.2 Breakpoints</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_C"></A>C</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX64">call stack</A></TD><TD valign=top><A HREF="gdb.html#SEC31">7. Examining the Stack</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX38">clear breakpoint</A></TD><TD valign=top><A HREF="gdb.html#SEC24">6.2.2 Clearing Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX132">command files</A></TD><TD valign=top><A HREF="gdb.html#SEC59">12.2 Command Files</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX48">conditions</A></TD><TD valign=top><A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX29">controlling terminal</A></TD><TD valign=top><A HREF="gdb.html#SEC18">5.4 Your Program's Input and Output</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX108">convenience variables</A></TD><TD valign=top><A HREF="gdb.html#SEC48">9.7 Convenience Variables</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX7">core dump file</A></TD><TD valign=top><A HREF="gdb.html#SEC6">2. Specifying GDB's Files</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_D"></A>D</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX39">delete breakpoints</A></TD><TD valign=top><A HREF="gdb.html#SEC24">6.2.2 Clearing Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX82">directories for source files</A></TD><TD valign=top><A HREF="gdb.html#SEC39">8.3 Specifying Source Directories</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX42">disabled breakpoints</A></TD><TD valign=top><A HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_E"></A>E</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX43">enabled breakpoints</A></TD><TD valign=top><A HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX20">environment (of your program)</A></TD><TD valign=top><A HREF="gdb.html#SEC16">5.2 Your Program's Environment</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX86">examining data</A></TD><TD valign=top><A HREF="gdb.html#SEC40">9. Examining Data</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX93">examining memory</A></TD><TD valign=top><A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX8">executable file</A></TD><TD valign=top><A HREF="gdb.html#SEC6">2. Specifying GDB's Files</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX5">exiting GDB</A></TD><TD valign=top><A HREF="gdb.html#SEC5">1. GDB Input Conventions</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX89">expressions</A></TD><TD valign=top><A HREF="gdb.html#SEC41">9.1 Expressions</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_F"></A>F</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX91">formatted output</A></TD><TD valign=top><A HREF="gdb.html#SEC44">9.4 Formats</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX65">frame</A></TD><TD valign=top><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX70">frame number</A></TD><TD valign=top><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX69">frame pointer</A></TD><TD valign=top><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_I"></A>I</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX50">ignore count (of breakpoint)</A></TD><TD valign=top><A HREF="gdb.html#SEC26">6.2.4 Break Conditions</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX133">init file</A></TD><TD valign=top><A HREF="gdb.html#SEC59">12.2 Command Files</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX66">initial frame</A></TD><TD valign=top><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX68">innermost frame</A></TD><TD valign=top><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_O"></A>O</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX67">outermost frame</A></TD><TD valign=top><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX92">output formats</A></TD><TD valign=top><A HREF="gdb.html#SEC44">9.4 Formats</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_P"></A>P</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX85">printing data</A></TD><TD valign=top><A HREF="gdb.html#SEC40">9. Examining Data</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_R"></A>R</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX28">redirection</A></TD><TD valign=top><A HREF="gdb.html#SEC18">5.4 Your Program's Input and Output</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX110">registers</A></TD><TD valign=top><A HREF="gdb.html#SEC49">9.8 Registers</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX127">returning from a function</A></TD><TD valign=top><A HREF="gdb.html#SEC56">11.4 Returning from a Function</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX16">running</A></TD><TD valign=top><A HREF="gdb.html#SEC14">5. Running Your Program Under GDB</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_S"></A>S</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#SEC38">searching</A></TD><TD valign=top><A HREF="gdb.html#SEC38">8.2 Searching Source Files</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX71">selected frame</A></TD><TD valign=top><A HREF="gdb.html#SEC32">7.1 Stack Frames</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX122">setting variables</A></TD><TD valign=top><A HREF="gdb.html#SEC53">11.1 Assignment to Variables</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX3">shell escape</A></TD><TD valign=top><A HREF="gdb.html#SEC5">1. GDB Input Conventions</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX81">source path</A></TD><TD valign=top><A HREF="gdb.html#SEC39">8.3 Specifying Source Directories</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX55">stepping</A></TD><TD valign=top><A HREF="gdb.html#SEC30">6.4 Stepping</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX9">symbol table</A></TD><TD valign=top><A HREF="gdb.html#SEC6">2. Specifying GDB's Files</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_U"></A>U</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX129">user-defined commands</A></TD><TD valign=top><A HREF="gdb.html#SEC58">12.1 User-Defined Commands</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_V"></A>V</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX104">value history</A></TD><TD valign=top><A HREF="gdb.html#SEC47">9.6 Value History</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
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<TR><TH><A NAME="cp_W"></A>W</TH><TD></TD><TD></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX95">word</A></TD><TD valign=top><A HREF="gdb.html#SEC45">9.4.1 Examining Memory</A></TD></TR>
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<TR><TD></TD><TD valign=top><A HREF="gdb.html#IDX25">working directory (of your program)</A></TD><TD valign=top><A HREF="gdb.html#SEC17">5.3 Your Program's Working Directory</A></TD></TR>
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<TR><TD COLSPAN=3> <HR></TD></TR>
|
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</TABLE><P></P><table><tr><th valign=top>Jump to: </th><td><A HREF="gdb.html#cp_$" style="text-decoration:none"><b>$</b></A>
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<A HREF="gdb.html#cp_." style="text-decoration:none"><b>.</b></A>
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<BR>
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<A HREF="gdb.html#cp_A" style="text-decoration:none"><b>A</b></A>
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<A HREF="gdb.html#cp_B" style="text-decoration:none"><b>B</b></A>
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<A HREF="gdb.html#cp_C" style="text-decoration:none"><b>C</b></A>
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<A HREF="gdb.html#cp_D" style="text-decoration:none"><b>D</b></A>
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<A HREF="gdb.html#cp_E" style="text-decoration:none"><b>E</b></A>
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<A HREF="gdb.html#cp_F" style="text-decoration:none"><b>F</b></A>
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<A HREF="gdb.html#cp_I" style="text-decoration:none"><b>I</b></A>
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<A HREF="gdb.html#cp_O" style="text-decoration:none"><b>O</b></A>
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<A HREF="gdb.html#cp_P" style="text-decoration:none"><b>P</b></A>
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<A HREF="gdb.html#cp_R" style="text-decoration:none"><b>R</b></A>
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<A HREF="gdb.html#cp_S" style="text-decoration:none"><b>S</b></A>
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<A HREF="gdb.html#cp_U" style="text-decoration:none"><b>U</b></A>
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<A HREF="gdb.html#cp_V" style="text-decoration:none"><b>V</b></A>
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|
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<A HREF="gdb.html#cp_W" style="text-decoration:none"><b>W</b></A>
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|
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</td></tr></table><br></P><P>
|
|
|
|
<HR SIZE="6">
|
|
<A NAME="SEC_Contents"></A>
|
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<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1>Table of Contents</H1>
|
|
<UL>
|
|
<A NAME="TOC1" HREF="gdb.html#SEC1">Summary of GDB</A>
|
|
<BR>
|
|
<A NAME="TOC2" HREF="gdb.html#SEC2">GDB General Public License</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC3" HREF="gdb.html#SEC3">Copying Policies</A>
|
|
<BR>
|
|
<A NAME="TOC4" HREF="gdb.html#SEC4">NO WARRANTY</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC5" HREF="gdb.html#SEC5">1. GDB Input Conventions</A>
|
|
<BR>
|
|
<A NAME="TOC6" HREF="gdb.html#SEC6">2. Specifying GDB's Files</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC7" HREF="gdb.html#SEC7">2.1 Specifying Files with Arguments</A>
|
|
<BR>
|
|
<A NAME="TOC8" HREF="gdb.html#SEC8">2.2 Specifying Files with Commands</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC9" HREF="gdb.html#SEC9">3. Options and Arguments for GDB</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC10" HREF="gdb.html#SEC10">3.1 Mode Options</A>
|
|
<BR>
|
|
<A NAME="TOC11" HREF="gdb.html#SEC11">3.2 File-specifying Options</A>
|
|
<BR>
|
|
<A NAME="TOC12" HREF="gdb.html#SEC12">3.3 Other Arguments</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC13" HREF="gdb.html#SEC13">4. Compiling Your Program for Debugging</A>
|
|
<BR>
|
|
<A NAME="TOC14" HREF="gdb.html#SEC14">5. Running Your Program Under GDB</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC15" HREF="gdb.html#SEC15">5.1 Your Program's Arguments</A>
|
|
<BR>
|
|
<A NAME="TOC16" HREF="gdb.html#SEC16">5.2 Your Program's Environment</A>
|
|
<BR>
|
|
<A NAME="TOC17" HREF="gdb.html#SEC17">5.3 Your Program's Working Directory</A>
|
|
<BR>
|
|
<A NAME="TOC18" HREF="gdb.html#SEC18">5.4 Your Program's Input and Output</A>
|
|
<BR>
|
|
<A NAME="TOC19" HREF="gdb.html#SEC19">5.5 Debugging an Already-Running Process</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC20" HREF="gdb.html#SEC20">6. Stopping and Continuing</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC21" HREF="gdb.html#SEC21">6.1 Signals</A>
|
|
<BR>
|
|
<A NAME="TOC22" HREF="gdb.html#SEC22">6.2 Breakpoints</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC23" HREF="gdb.html#SEC23">6.2.1 Setting Breakpoints</A>
|
|
<BR>
|
|
<A NAME="TOC24" HREF="gdb.html#SEC24">6.2.2 Clearing Breakpoints</A>
|
|
<BR>
|
|
<A NAME="TOC25" HREF="gdb.html#SEC25">6.2.3 Disabling Breakpoints</A>
|
|
<BR>
|
|
<A NAME="TOC26" HREF="gdb.html#SEC26">6.2.4 Break Conditions</A>
|
|
<BR>
|
|
<A NAME="TOC27" HREF="gdb.html#SEC27">6.2.5 Commands Executed on Breaking</A>
|
|
<BR>
|
|
<A NAME="TOC28" HREF="gdb.html#SEC28">6.2.6 "Cannot Insert Breakpoints" Error</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC29" HREF="gdb.html#SEC29">6.3 Continuing</A>
|
|
<BR>
|
|
<A NAME="TOC30" HREF="gdb.html#SEC30">6.4 Stepping</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC31" HREF="gdb.html#SEC31">7. Examining the Stack</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC32" HREF="gdb.html#SEC32">7.1 Stack Frames</A>
|
|
<BR>
|
|
<A NAME="TOC33" HREF="gdb.html#SEC33">7.2 Backtraces</A>
|
|
<BR>
|
|
<A NAME="TOC34" HREF="gdb.html#SEC34">7.3 Selecting a Frame</A>
|
|
<BR>
|
|
<A NAME="TOC35" HREF="gdb.html#SEC35">7.4 Information on a Frame</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC36" HREF="gdb.html#SEC36">8. Examining Source Files</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC37" HREF="gdb.html#SEC37">8.1 Printing Source Lines</A>
|
|
<BR>
|
|
<A NAME="TOC38" HREF="gdb.html#SEC38">8.2 Searching Source Files</A>
|
|
<BR>
|
|
<A NAME="TOC39" HREF="gdb.html#SEC39">8.3 Specifying Source Directories</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC40" HREF="gdb.html#SEC40">9. Examining Data</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC41" HREF="gdb.html#SEC41">9.1 Expressions</A>
|
|
<BR>
|
|
<A NAME="TOC42" HREF="gdb.html#SEC42">9.2 Program Variables</A>
|
|
<BR>
|
|
<A NAME="TOC43" HREF="gdb.html#SEC43">9.3 Artificial Arrays</A>
|
|
<BR>
|
|
<A NAME="TOC44" HREF="gdb.html#SEC44">9.4 Formats</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC45" HREF="gdb.html#SEC45">9.4.1 Examining Memory</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC46" HREF="gdb.html#SEC46">9.5 Automatic Display</A>
|
|
<BR>
|
|
<A NAME="TOC47" HREF="gdb.html#SEC47">9.6 Value History</A>
|
|
<BR>
|
|
<A NAME="TOC48" HREF="gdb.html#SEC48">9.7 Convenience Variables</A>
|
|
<BR>
|
|
<A NAME="TOC49" HREF="gdb.html#SEC49">9.8 Registers</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC50" HREF="gdb.html#SEC50">9.8.1 Examples</A>
|
|
<BR>
|
|
</UL>
|
|
</UL>
|
|
<A NAME="TOC51" HREF="gdb.html#SEC51">10. Examining the Symbol Table</A>
|
|
<BR>
|
|
<A NAME="TOC52" HREF="gdb.html#SEC52">11. Altering Execution</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC53" HREF="gdb.html#SEC53">11.1 Assignment to Variables</A>
|
|
<BR>
|
|
<A NAME="TOC54" HREF="gdb.html#SEC54">11.2 Continuing at a Different Address</A>
|
|
<BR>
|
|
<A NAME="TOC55" HREF="gdb.html#SEC55">11.3 Giving the Program a Signal</A>
|
|
<BR>
|
|
<A NAME="TOC56" HREF="gdb.html#SEC56">11.4 Returning from a Function</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC57" HREF="gdb.html#SEC57">12. Canned Sequences of Commands</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC58" HREF="gdb.html#SEC58">12.1 User-Defined Commands</A>
|
|
<BR>
|
|
<A NAME="TOC59" HREF="gdb.html#SEC59">12.2 Command Files</A>
|
|
<BR>
|
|
<A NAME="TOC60" HREF="gdb.html#SEC60">12.3 Commands for Controlled Output</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC61" HREF="gdb.html#SEC61">13. Using GDB under GNU Emacs</A>
|
|
<BR>
|
|
<A NAME="TOC62" HREF="gdb.html#SEC62">14. Remote Kernel Debugging</A>
|
|
<BR>
|
|
<UL>
|
|
<A NAME="TOC63" HREF="gdb.html#SEC63">14.1 Commands for Remote Debugging</A>
|
|
<BR>
|
|
</UL>
|
|
<A NAME="TOC64" HREF="gdb.html#SEC64">Command Index</A>
|
|
<BR>
|
|
<A NAME="TOC65" HREF="gdb.html#SEC65">Concept Index</A>
|
|
<BR>
|
|
</UL>
|
|
<HR SIZE=1>
|
|
<A NAME="SEC_OVERVIEW"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1>Short Table of Contents</H1>
|
|
<BLOCKQUOTE>
|
|
<A NAME="TOC1" HREF="gdb.html#SEC1">Summary of GDB</A>
|
|
<BR>
|
|
<A NAME="TOC2" HREF="gdb.html#SEC2">GDB General Public License</A>
|
|
<BR>
|
|
<A NAME="TOC5" HREF="gdb.html#SEC5">1. GDB Input Conventions</A>
|
|
<BR>
|
|
<A NAME="TOC6" HREF="gdb.html#SEC6">2. Specifying GDB's Files</A>
|
|
<BR>
|
|
<A NAME="TOC9" HREF="gdb.html#SEC9">3. Options and Arguments for GDB</A>
|
|
<BR>
|
|
<A NAME="TOC13" HREF="gdb.html#SEC13">4. Compiling Your Program for Debugging</A>
|
|
<BR>
|
|
<A NAME="TOC14" HREF="gdb.html#SEC14">5. Running Your Program Under GDB</A>
|
|
<BR>
|
|
<A NAME="TOC20" HREF="gdb.html#SEC20">6. Stopping and Continuing</A>
|
|
<BR>
|
|
<A NAME="TOC31" HREF="gdb.html#SEC31">7. Examining the Stack</A>
|
|
<BR>
|
|
<A NAME="TOC36" HREF="gdb.html#SEC36">8. Examining Source Files</A>
|
|
<BR>
|
|
<A NAME="TOC40" HREF="gdb.html#SEC40">9. Examining Data</A>
|
|
<BR>
|
|
<A NAME="TOC51" HREF="gdb.html#SEC51">10. Examining the Symbol Table</A>
|
|
<BR>
|
|
<A NAME="TOC52" HREF="gdb.html#SEC52">11. Altering Execution</A>
|
|
<BR>
|
|
<A NAME="TOC57" HREF="gdb.html#SEC57">12. Canned Sequences of Commands</A>
|
|
<BR>
|
|
<A NAME="TOC61" HREF="gdb.html#SEC61">13. Using GDB under GNU Emacs</A>
|
|
<BR>
|
|
<A NAME="TOC62" HREF="gdb.html#SEC62">14. Remote Kernel Debugging</A>
|
|
<BR>
|
|
<A NAME="TOC64" HREF="gdb.html#SEC64">Command Index</A>
|
|
<BR>
|
|
<A NAME="TOC65" HREF="gdb.html#SEC65">Concept Index</A>
|
|
<BR>
|
|
|
|
</BLOCKQUOTE>
|
|
<HR SIZE=1>
|
|
<A NAME="SEC_About"></A>
|
|
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
|
|
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Top">Top</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_Contents">Contents</A>]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
|
|
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="gdb.html#SEC_About"> ? </A>]</TD>
|
|
</TR></TABLE>
|
|
<H1>About this document</H1>
|
|
This document was generated by <I>root</I> on <I>January, 23 2003</I>
|
|
using <A HREF="http://www.mathematik.uni-kl.de/~obachman/Texi2html
|
|
"><I>texi2html</I></A>
|
|
<P></P>
|
|
The buttons in the navigation panels have the following meaning:
|
|
<P></P>
|
|
<table border = "1">
|
|
<TR>
|
|
<TH> Button </TH>
|
|
<TH> Name </TH>
|
|
<TH> Go to </TH>
|
|
<TH> From 1.2.3 go to</TH>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[ < ] </TD>
|
|
<TD ALIGN="CENTER">
|
|
Back
|
|
</TD>
|
|
<TD>
|
|
previous section in reading order
|
|
</TD>
|
|
<TD>
|
|
1.2.2
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[ > ] </TD>
|
|
<TD ALIGN="CENTER">
|
|
Forward
|
|
</TD>
|
|
<TD>
|
|
next section in reading order
|
|
</TD>
|
|
<TD>
|
|
1.2.4
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[ << ] </TD>
|
|
<TD ALIGN="CENTER">
|
|
FastBack
|
|
</TD>
|
|
<TD>
|
|
previous or up-and-previous section
|
|
</TD>
|
|
<TD>
|
|
1.1
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[ Up ] </TD>
|
|
<TD ALIGN="CENTER">
|
|
Up
|
|
</TD>
|
|
<TD>
|
|
up section
|
|
</TD>
|
|
<TD>
|
|
1.2
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[ >> ] </TD>
|
|
<TD ALIGN="CENTER">
|
|
FastForward
|
|
</TD>
|
|
<TD>
|
|
next or up-and-next section
|
|
</TD>
|
|
<TD>
|
|
1.3
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[Top] </TD>
|
|
<TD ALIGN="CENTER">
|
|
Top
|
|
</TD>
|
|
<TD>
|
|
cover (top) of document
|
|
</TD>
|
|
<TD>
|
|
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[Contents] </TD>
|
|
<TD ALIGN="CENTER">
|
|
Contents
|
|
</TD>
|
|
<TD>
|
|
table of contents
|
|
</TD>
|
|
<TD>
|
|
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[Index] </TD>
|
|
<TD ALIGN="CENTER">
|
|
Index
|
|
</TD>
|
|
<TD>
|
|
concept index
|
|
</TD>
|
|
<TD>
|
|
|
|
</TD>
|
|
</TR>
|
|
<TR>
|
|
<TD ALIGN="CENTER">
|
|
[ ? ] </TD>
|
|
<TD ALIGN="CENTER">
|
|
About
|
|
</TD>
|
|
<TD>
|
|
this page
|
|
</TD>
|
|
<TD>
|
|
|
|
</TD>
|
|
</TR>
|
|
</TABLE>
|
|
<P></P>
|
|
where the <STRONG> Example </STRONG> assumes that the current position
|
|
is at <STRONG> Subsubsection One-Two-Three </STRONG> of a document of
|
|
the following structure:
|
|
<UL>
|
|
<LI> 1. Section One </LI>
|
|
<UL>
|
|
<LI>1.1 Subsection One-One</LI>
|
|
<UL>
|
|
<LI> ... </LI>
|
|
</UL>
|
|
<LI>1.2 Subsection One-Two</LI>
|
|
<UL>
|
|
<LI>1.2.1 Subsubsection One-Two-One
|
|
</LI><LI>1.2.2 Subsubsection One-Two-Two
|
|
</LI><LI>1.2.3 Subsubsection One-Two-Three <STRONG>
|
|
<== Current Position </STRONG>
|
|
</LI><LI>1.2.4 Subsubsection One-Two-Four
|
|
</LI></UL>
|
|
<LI>1.3 Subsection One-Three</LI>
|
|
<UL>
|
|
<LI> ... </LI>
|
|
</UL>
|
|
<LI>1.4 Subsection One-Four</LI>
|
|
</UL>
|
|
</UL>
|
|
|
|
<HR SIZE=1>
|
|
<BR>
|
|
<FONT SIZE="-1">
|
|
This document was generated
|
|
by <I>root</I> on <I>January, 23 2003</I>
|
|
using <A HREF="http://www.mathematik.uni-kl.de/~obachman/Texi2html
|
|
"><I>texi2html</I></A>
|
|
|
|
</BODY>
|
|
</HTML>
|