179 lines
5.2 KiB
HTML
179 lines
5.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<html>
|
|
<head>
|
|
<meta name="generator" content="HTML Tidy, see www.w3.org">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
|
<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
|
|
<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
|
|
<title><sys/sem.h></title>
|
|
</head>
|
|
<body bgcolor="white">
|
|
<script type="text/javascript" language="JavaScript" src="../../jscript/dotcode.js">
|
|
</script>
|
|
|
|
<basefont size="3"> <a name="<sys/sem.h>"></a> <a name="tag_13_59"></a><!-- <sys/sem.h> -->
|
|
<!--header start-->
|
|
<center><font size="2">The Open Group Base Specifications Issue 6<br>
|
|
IEEE Std 1003.1-2001<br>
|
|
Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
|
|
|
|
<!--header end-->
|
|
<hr size="2" noshade>
|
|
<h4><a name="tag_13_59_01"></a>NAME</h4>
|
|
|
|
<blockquote>sys/sem.h - XSI semaphore facility</blockquote>
|
|
|
|
<h4><a name="tag_13_59_02"></a>SYNOPSIS</h4>
|
|
|
|
<blockquote class="synopsis">
|
|
<div class="box"><tt><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../../images/opt-start.gif" alt=
|
|
"[Option Start]" border="0"> #include <sys/sem.h> <img src="../../images/opt-end.gif" alt="[Option End]" border=
|
|
"0"></tt></div>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_13_59_03"></a>DESCRIPTION</h4>
|
|
|
|
<blockquote>
|
|
<p>The <i><sys/sem.h></i> header shall define the following constants and structures.</p>
|
|
|
|
<p>Semaphore operation flags:</p>
|
|
|
|
<dl compact>
|
|
<dt>SEM_UNDO</dt>
|
|
|
|
<dd>Set up adjust on exit entry.</dd>
|
|
</dl>
|
|
|
|
<p>Command definitions for the <a href="../../functions/semctl.html"><i>semctl</i>()</a> function shall be provided as follows:</p>
|
|
|
|
<dl compact>
|
|
<dt>GETNCNT</dt>
|
|
|
|
<dd>Get <i>semncnt</i>.</dd>
|
|
|
|
<dt>GETPID</dt>
|
|
|
|
<dd>Get <i>sempid</i>.</dd>
|
|
|
|
<dt>GETVAL</dt>
|
|
|
|
<dd>Get <i>semval</i>.</dd>
|
|
|
|
<dt>GETALL</dt>
|
|
|
|
<dd>Get all cases of <i>semval</i>.</dd>
|
|
|
|
<dt>GETZCNT</dt>
|
|
|
|
<dd>Get <i>semzcnt</i>.</dd>
|
|
|
|
<dt>SETVAL</dt>
|
|
|
|
<dd>Set <i>semval</i>.</dd>
|
|
|
|
<dt>SETALL</dt>
|
|
|
|
<dd>Set all cases of <i>semval</i>.</dd>
|
|
</dl>
|
|
|
|
<p>The <b>semid_ds</b> structure shall contain the following members:</p>
|
|
|
|
<pre>
|
|
<tt>struct ipc_perm sem_perm </tt> Operation permission structure. <tt>
|
|
unsigned short sem_nsems</tt> Number of semaphores in set. <tt>
|
|
time_t sem_otime</tt> Last <i>semop</i>
|
|
() time. <tt>
|
|
time_t sem_ctime</tt> Last time changed by <i>semctl</i>
|
|
(). <tt>
|
|
</tt>
|
|
</pre>
|
|
|
|
<p>The <b>pid_t</b>, <b>time_t</b>, <b>key_t</b>, and <b>size_t</b> types shall be defined as described in <a href=
|
|
"../sys/types.h.html#tag_13_67"><i><sys/types.h></i></a> .</p>
|
|
|
|
<p>A semaphore shall be represented by an anonymous structure containing the following members:</p>
|
|
|
|
<pre>
|
|
<tt>unsigned short semval </tt> Semaphore value. <tt>
|
|
pid_t sempid </tt> Process ID of last operation. <tt>
|
|
unsigned short semncnt </tt> Number of processes waiting for <i>semval</i> <tt>
|
|
</tt> to become greater than current value. <tt>
|
|
unsigned short semzcnt </tt> Number of processes waiting for <i>semval</i> <tt>
|
|
</tt> to become 0. <tt>
|
|
</tt>
|
|
</pre>
|
|
|
|
<p>The <b>sembuf</b> structure shall contain the following members:</p>
|
|
|
|
<pre>
|
|
<tt>unsigned short sem_num </tt> Semaphore number. <tt>
|
|
short sem_op </tt> Semaphore operation. <tt>
|
|
short sem_flg </tt> Operation flags. <tt>
|
|
</tt>
|
|
</pre>
|
|
|
|
<p>The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.</p>
|
|
|
|
<pre>
|
|
<tt>int semctl(int, int, int, ...);
|
|
int semget(key_t, int, int);
|
|
int semop(int, struct sembuf *, size_t);
|
|
</tt>
|
|
</pre>
|
|
|
|
<p>In addition, all of the symbols from <a href="../../basedefs/sys/ipc.h.html"><i><sys/ipc.h></i></a> shall be defined when
|
|
this header is included.</p>
|
|
</blockquote>
|
|
|
|
<hr>
|
|
<div class="box"><em>The following sections are informative.</em></div>
|
|
|
|
<h4><a name="tag_13_59_04"></a>APPLICATION USAGE</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_13_59_05"></a>RATIONALE</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_13_59_06"></a>FUTURE DIRECTIONS</h4>
|
|
|
|
<blockquote>
|
|
<p>None.</p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_13_59_07"></a>SEE ALSO</h4>
|
|
|
|
<blockquote>
|
|
<p><a href="../sys/ipc.h.html#tag_13_54"><i><sys/ipc.h></i></a> , <a href=
|
|
"../sys/types.h.html#tag_13_67"><i><sys/types.h></i></a> , <a href="../../functions/semctl.html"><i>semctl</i>()</a>, <a
|
|
href="../../functions/semget.html"><i>semget</i>()</a>, <a href="../../functions/semop.html"><i>semop</i>()</a></p>
|
|
</blockquote>
|
|
|
|
<h4><a name="tag_13_59_08"></a>CHANGE HISTORY</h4>
|
|
|
|
<blockquote>
|
|
<p>First released in Issue 2. Derived from System V Release 2.0.</p>
|
|
</blockquote>
|
|
|
|
<div class="box"><em>End of informative text.</em></div>
|
|
|
|
<hr>
|
|
<hr size="2" noshade>
|
|
<center><font size="2"><!--footer start-->
|
|
UNIX ® is a registered Trademark of The Open Group.<br>
|
|
POSIX ® is a registered Trademark of The IEEE.<br>
|
|
[ <a href="../../mindex.html">Main Index</a> | <a href="../../basedefs/contents.html">XBD</a> | <a href=
|
|
"../../utilities/contents.html">XCU</a> | <a href="../../functions/contents.html">XSH</a> | <a href=
|
|
"../../xrat/contents.html">XRAT</a> ]</font></center>
|
|
|
|
<!--footer end-->
|
|
<hr size="2" noshade>
|
|
</body>
|
|
</html>
|
|
|