This is Info file INSTALL, produced by Makeinfo-1.44 from the input file manual/maint.texinfo. Library Maintenance ******************** How to Install the GNU C Library ================================= Installation of the GNU C library is relatively simple. You need the latest version of GNU `make'. If you do not have GNU `make', life is more difficult. We recommend porting GNU `make' to your system rather than trying to install the GNU C library without it. *Really.* To configure the GNU C library for your system, run the script `configure' with `sh'. You must give as an argument to the script a word describing your system, such as `sun4' or `hp300'. By default, the `configure' script will set things up to build things into a subdirectory of the library source directory whose name is the name of the system you configure for. For example, `configure sun4' creates and uses a directory called `sun4'. If you give a second argument to `configure', that is used as the directory name instead. You can build for several machines from the same source directory, by specifying the subdirectory that `configure' created when you configured for that machine in the `make' variable `ARCH'. For example, use `make ARCH=sun4', or put `ARCH=sun4' in your environment. If you don't specify a value for `ARCH', the variable `machine' is used if defined; otherwise `make' will build for the configuration most recently configured for. Now edit the file `Makeconfig' to set the compilation parameters, and what directories to install the library and header files in. See the comments in `Makeconfig' for the details. If you are building for several machines, you can put just the values specific to a particular machine in a file called `Makeconfig' in the object directory for that machine (for example, `sun4/Makeconfig'). This should *not* be an edited copy of `Makeconfig'. Make a new file containing just the variables in `Makeconfig' that you want to set specially for the particular machine. These values will override the values defined in `Makeconfig'. Some of the machine-dependent code for some machines uses extensions in the GNU C compiler, so you may need to compile the library with GCC. (In fact, all of the existing complete ports require GCC.) If possible, you should use the GNU linker, GNU `ld', when linking programs with the GNU C library. If you are going to use GNU `ld', be sure to specify `-DHAVE_GNU_LD' in `Makeconfig'. To build the library and header files, type `make'. This will produce a lot of output, some of which looks like errors from `make' (but isn't). Look for error messages from `make' containing `***'. Those indicate that something is really wrong. Using the `-w' option to `make' may make the output easier to understand (this option tells `make' to print messages telling you what subdirectories it is working on). To install the library and header files, type `make install', after setting the installation directories in `Makeconfig' (or `MACHINE/Makeconfig'). This will build things if necessary, before installing them. Reporting Bugs =============== There are probably bugs in the GNU C library. If you report them, they will get fixed. If you don't, no one will ever know about them and they will remain unfixed for all eternity, if not longer. To report a bug, first you must find it. Hopefully, this will be the hard part. Once you've found a bug, make sure it's really a bug. A good way to do this is to see if the GNU C library behaves the same way some other C library does. If so, probably you are wrong and the libraries are right. If not, one of the libraries is probably wrong. Once you're sure you've found a bug, try to narrow it down to the smallest test case that reproduces the problem. In the case of a C library, you really only need to narrow it down to one library function call, if possible. This should not be too difficult. The final step when you have a simple test case is to report the bug. When reporting a bug, send your test case, the results you got, the results you expected, what you think the problem might be (if you've thought of anything), your system type, and the version of the GNU C library which you are using. If you think you have found some way in which the GNU C library does not conform to the ANSI and POSIX standards (*note Standards and Portability::.), that is definitely a bug. Report it! Send bug reports to Internet address `bug-gnu-libc@prep.ai.mit.edu' or UUCP path `mit-eddie!prep.ai.mit.edu!bug-gnu-libc'. If you have other problems with installation, use, or the documentation, please report those as well. Porting the GNU C Library ========================== The GNU C library is written to be easily portable to a variety of machines and operating systems. Machine- and operating system-dependent functions are well separated to make it easy to add implementations for new machines or operating systems. This section describes the layout of the library source tree and explains the mechanisms used to select machine-dependent code to use. The process of building the library is driven by the makefiles, which make heavy use of GNU `make' features. The makefiles are very complex, and you probably don't want to try to understand them. But what they do is fairly straightforward, and only requires that you define a few variables in the right places. The library sources are divided into subdirectories, grouped by topic. The `string' subdirectory has all the string-manipulation functions, `stdio' has all the standard I/O functions, etc. Each subdirectory contains a simple makefile, called `Makefile', which defines a few `make' variables and then includes the global makefile `Rules' with a line like: include ../Rules The basic variables that a subdirectory makefile defines are: `subdir' The name of the subdirectory, for example `stdio'. This variable *must* be defined. `headers' The names of the header files in this section of the library, such as `stdio.h'. `routines' `aux' The names of the modules (source files) in this section of the library. These should be simple names, such as `strlen' (rather than complete file names, such as `strlen.c'). The idea is that `routines' is for modules that define functions in the library, and `aux' is for auxiliary modules containing things like data definitions. But the values of `routines' and `aux' are concatenated, so there really is no practical difference. `tests' The names of test programs for this section of the library. These should be simple names, such as `tester' (rather than complete file names, such as `tester.c'). `make tests' will build and run all the test programs. If a test program needs input, put the test data in a file called `TEST-PROGRAM.input'; it will given to the test program on its standard input. If a test program wants to be run with arguments, put the arguments (all on a single line) in a file called `TEST-PROGRAM.args'. `others' The names of "other" in programs associated with this section of the library. These are programs which are not tests per se, but are other small programs included with the library. These are built by `make others'. `install-lib' `install-data' `install' Files to be installed by `make install'. Things listed in `install-lib' are installed in the directory specified by `libdir' in `Makeconfig' (*note Installation::.). Things listed in `install-data' are installed in the directory specified by `datadir' in `Makeconfig'. Things listed in `install' are installed in the directory specified by `bindir' in `Makeconfig'. `distribute' Other files from this subdirectory which should be put into a distribution tar file. The source and header files listed in the other standard variables, and the makefile itself, need not be listed here. Only define `distribute' if there are files used in an unusual way that should go into the distribution. All the machine-dependent and operating system-dependent files in the library are in the subdirectory `sysdeps' under the top-level library source directory. This directory contains a hierarchy of directories. Each subdirectory of `sysdeps' contains source files for a particular machine or operating system, or for a class of machine or operating system. A configuration is specified by an ordered list of these subdirectories. Each subdirectory implicitly appends its parent directory to the list. For example, specifying the list `unix/bsd/hp9k3bsd' is equivalent to specifying the list `unix/bsd/hp9k3bsd unix/bsd unix'. A subdirectory can also specify that it implies other subdirectories which are not directly above it in the directory hierarchy. If the file `Implies' exists in a subdirectory, it lists other subdirectories of `sysdeps' which are appended to the list, appearing after the subdirectory containing the `Implies' file. Lines in an `Implies' file that begin with a `#' character are ignored as comments. For example, `unix/bsd/hp9k3bsd/Implies' contains: # HP 9000 series 300 is 68k. m68k Since `m68k/Implies' contains: # 68k uses IEEE 754 floating point. ieee754 and `unix/bsd/Implies' contains: # BSD has Internet-related things. unix/inet and `unix/Implies' contains: posix the final list is ` unix/bsd/hp9k3bsd unix/bsd m68k unix/inet unix ieee754 posix '. There are two "special" subdirectories of `sysdeps', `generic' and `stub'. These two are always implicitly appended to the list of subdirectories (in that order), so you needn't put them in an `Implies' file, and you should not create any subdirectories under them. `generic' is for things that can be implemented in machine-independent C, using only other machine-independent functions in the C library. `stub' is for "stub" versions of functions which cannot be implemented on a particular machine or operating system. These functions always return an error, and set `errno' to `ENOSYS' (Function not implemented). A source file is known to be system-dependent by its having a version in `generic' or `stub', so every system-dependent function should have a generic or stub implementation (there is no point in having both). If you come across a file that is in one of the main source directories (`string', `stdio', etc.), and you want to write a machine- or operating system-dependent version of it, move the file into `sysdeps/generic' and write your new implementation in the appropriate system-specific subdirectory. Note that if a file is to be system-dependent, it *must not* appear in one of the main source directories. There are a few special files that may exist in each subdirectory of `sysdeps': `Makefile' A makefile for this machine or operating system, or class of machine or operating system. This file is included by the library makefile `Makerules', which is used by the top-level makefile and the subdirectory makefiles. It can change the variables set in the including makefile or add new rules. It can use GNU `make' conditional commands based on the variable `subdir' (see above) to select different sets of variables and rules for different sections of the library. It can also set the `make' variable `sysdep-routines', to specify extra modules to be included in the library. You should use `sysdep-routines' rather than adding modules to `routines' because the latter is used in determining what to distribute for each subdirectory of the main source tree. Each makefile in a subdirectory in the ordered list of subdirectories to be searched is included in order. Since several system-dependent makefiles may be included, each should append to `sysdep-routines' rather than simply setting it: sysdep-routines := $(sysdep-routines) foo bar `Subdirs' This file contains the names of new whole subdirectories under the top-level library source tree that should be included for this system. These subdirectories are treated just like the system-independent subdirectories in the library source tree, such as `stdio' and `math'. Use this when there are whole new sets of routines and header files that should go into the library for the system this subdirectory of `sysdeps' implements. For example, `sysdeps/unix/inet/Subdirs' contains `inet'; the `inet' directory contains various network-oriented operations which only make sense to put in the library on systems that support the Internet. `Dist' This file contains the names of files (relative the the subdirectory of `sysdeps' in which it appears) which should be included in the distribution. List any new files used by rules in the `Makefile' in the same directory, or header files used by the source files in that directory. You don't need to list files that are implementations (either C or assembly source) of routines whose names are given in the machine-independent makefiles in the main source tree. That is the general system for how system-dependencies are isolated. The rest of this section describes details of particular implementations for classes of systems, and how existing classes and systems are organized. The Layout of the `sysdeps' Directory Hierarchy ------------------------------------------------ Different machine architectures are generally at the top level of the `sysdeps' hierarchy. For example, `sysdeps/sparc' and `sysdeps/m68k'. These contain things specific to those machine architectures (perhaps with subdirectories for specialization of those architectures, such as `sysdeps/m68k/68881'), but not specific to any particular operating system. Things specific to a particular operating system on a particular machine are canonically put in a subdirectory in the section of the hierarchy for the operating system, usually with an `Implies' file referring to the top-level subdirectory under `sysdeps' for the particular machine. For example, `unix/bsd/hp9k3bsd' implies `m68k'. There are a few directories at the top level of the `sysdeps' hierarchy that are not for particular machine architectures. `generic' `stub' As described above (*note Porting::.), these are the two subdirectories that every configuration uses, usually last. `ieee754' This directory is for code using the IEEE 754 floating-point format, where the C type `float' is IEEE 754 single-precision format, and `double' is IEEE 754 double-precision format. Usually this is directory is referred to in the `Implies' file in a machine architecture-specific directory, such as `m68k/Implies'. `posix' This directory contains implementations of things in the library in terms of POSIX.1 functions. This includes some of the POSIX.1 functions themselves. Of course, POSIX.1 cannot be completely implemented in terms of itself, so a configuration using just `posix' cannot be complete. `unix' This is the directory for Unix-like things. See *Note Porting to Unix::. `unix' implies `posix'. `mach' This is the directory for things based on the Mach microkernel from CMU (including the GNU operating system). Other basic operating systems (VMS, for example) would have their own directories at the top level of the `sysdeps' hierarchy, parallel to `unix' and `mach'. Porting the GNU C Library to Unix Systems ------------------------------------------ Most Unix systems are fundamentally very similar. There are variations between different machines, and variations in what facilities are provided by the kernel. But the interface to the operating system facilities is, for the most part, pretty uniform and simple. The code for Unix systems is in the directory `unix', at the top level of the `sysdeps' hierarchy. This directory contains subdirectories (and subdirectory trees) for various Unix variants. The routines which are system calls in most Unix systems are implemented in assembly code in files in `sysdeps/unix'. These files are named with a suffix of `.S'; for example, `__open.S'. Files ending in `.S' are run through the C preprocessor before being fed to the assembler. These files all use a set of macros that should be defined in `sysdep.h'. The `sysdep.h' in `sysdeps/unix' does not adequately define them. They must be defined for the particular machine and operating system variant. See `sysdeps/unix/sysdep.h' and the machine-specific `sysdep.h' implementations to see what these macros are and what they should do. The system-specific makefile for the `unix' directory, `sysdeps/unix/Makefile', gives rules to generate several files from the Unix system you are building the library on (which is assumed to be the target system you are building the library *for*). All the generated files are put in the directory where the object files are kept; they should not affect the source tree itself. The files generated are: `ioctls.h', `errnos.h', `sys/param.h', and `errlist.c' (for the `stdio' section of the library). Compatibility with Traditional C ================================= Although the GNU C library implements the ANSI C library facilities, you *can* use the GNU C library with traditional, "pre-ANSI" C compilers. However, there are a couple things you need to watch out for. You must include a different set of header files when compiling your program using a traditional C compiler than when compiling with an ANSI C compiler. (This is because traditional C compilers do not understand the function prototypes used in the ANSI C header files. On the other hand, if you are using an ANSI C compiler like GCC, you should use the ANSI C header files because the prototypes permit the compiler to do a better job of detecting errors in calls to library functions.) You can tell the C compiler what directories to search for header files by using the `-I' option. Set the `trad-incldir' variable in `Makeconfig' to choose where to install this set of header files. You also need to be careful because the content and organization of the GNU C library header files differs from that of traditional C implementations. This means you may need to make changes to your program in order to get it to compile. Contributors to the GNU C Library ================================== The GNU C library was written almost entirely by Roland McGrath. Some parts of the library were contributed by other people. * The `getopt' and related functions were written by Richard Stallman, David J. MacKenzie, and Roland McGrath. * The random number generation functions `random', `srandom', `setstate' and `initstate', which are also the basis for the `rand' and `srand' functions, were written by Earl T. Cohen for the University of California at Berkeley and are copyrighted by the Regents of the University of California. They have undergone minor changes to fit into the GNU C library and to fit the ANSI C standard, but the functional code is Berkeley's. * Most of the math functions are taken from 4.4 BSD, and are copyrighted by the Regents of the University of California. They have been modified only slightly to work with the GNU C library. * The `qsort' function was written by Douglas C. Schmidt. * The memory allocation functions `malloc', `realloc' and `free' and related code were written by Michael J. Haertel. * Fast implementations of many of the string functions (`memcpy', `strlen', etc.) were written by Torbjorn Granlund. * Some of the support code for Mach is taken from Mach 3.0, from CMU, and is under the following copyright terms: Mach Operating System Copyright (c) 1991,1990,1989 Carnegie Mellon University All Rights Reserved. Permission to use, copy, modify and distribute this software and its documentation is hereby granted, provided that both the copyright notice and this permission notice appear in all copies of the software, derivative works or modified versions, and any portions thereof, and that both notices appear in supporting documentation. CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. Carnegie Mellon requests users of this software to return to Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU School of Computer Science Carnegie Mellon University Pittsburgh PA 15213-3890 any improvements or extensions that they make and grant Carnegie Mellon the rights to redistribute these changes. * The `tar.h' header file was written by David J. MacKenzie.  Tag Table: Node: Maintenance97 Node: Installation141 Node: Reporting Bugs3131 Node: Porting4714 Node: Hierarchy Conventions13569 Node: Porting to Unix15729 Node: Compatibility with Traditional C17429 Node: Contributors to the GNU C Library18645  End Tag Table