249 lines
6.3 KiB
HTML
249 lines
6.3 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>sigpending()--Examine Pending Signals</title>
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<!-- Begin Header Records ========================================== -->
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<!-- UNIX5 SCRIPT J converted by B2H R4.1 (346) (CMS) by V2KEA304 -->
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<!-- at RCHVMW2 on 17 Feb 1999 at 11:05:09 -->
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<!-- Edited by Kersten Feb 02 -->
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<!-- This file has undergone html cleanup June 2002 by JET -->
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<!--End Header Records -->
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<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</head>
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<body>
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<a name="Top_Of_Page"></a>
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<!-- Java sync-link -->
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<script type="text/javascript" language="Javascript" src="../rzahg/synch.js">
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</script>
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<h2>sigpending()--Examine Pending Signals</h2>
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<div class="box" style="width: 60%;">
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<br>
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Syntax<br>
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<pre>
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#include <signal.h>
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int sigpending( sigset_t <em>*set</em> );
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</pre>
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<br>
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Service Program Name: QPOSSRV1<br>
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<!-- iddvc RMBR -->
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<p>The <strong>sigpending()</strong> function returns signals that are blocked
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from delivery and pending for either the calling thread or the process. This
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information is represented as a signal set stored in <em>set</em>. For more
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information on examining the signal set pointed to by <em>set</em>, see <a
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href="sigismbr.htm">sigismember()--Test for Signal in Signal Set</a>.</p>
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<br>
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<!-- Please NOTE: DO NOT DELETE THIS SECTION if this API has no authorities and locks. -->
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<!-- Instead, use the commented out coding below to indicate NONE. -->
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<h3>Authorities and Locks</h3>
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<!-- Use this if there are no authorities and locks. -->
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<p>None.</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt><strong><em>*set</em></strong></dt>
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<dd>(Output) A pointer to the space where the signal set information is
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stored.</dd>
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</dl>
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<br>
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<h3>Return Value</h3>
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<table cellpadding="5">
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<!-- cols="5 95" -->
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<tr>
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<td align="left" valign="top"><em>0</em></td>
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<td align="left" valign="top"><strong>sigpending()</strong> was
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successful.</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>-1</em></td>
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<td align="left" valign="top"><strong>sigpending()</strong> was not successful.
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The <em>errno</em> variable is set to indicate the error.</td>
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</tr>
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</table>
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<br>
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<br>
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<h3>Error Conditions</h3>
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<p>If <strong>sigpending()</strong> is not successful, <em>errno</em> usually
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indicates the following error. Under some conditions, <em>errno</em> could
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indicate an error other than that listed here.</p>
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<dl>
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<dt><em>[ENOTSIGINIT]</em></dt>
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<dd>
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<p>Process not enabled for signals.</p>
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<p>An attempt was made to call a signal function under one of the following
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conditions:</p>
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<ul>
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<li>The signal function is being called for a process that is not enabled for
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asynchronous signals.<br>
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<br>
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</li>
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<li>The signal function is being called when the system signal controls have
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not been initialized.</li>
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</ul>
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</dd>
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</dl>
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<br>
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<h3>Related Information</h3>
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<ul>
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<li>The <<strong>signal.h</strong>> file (see <a href="unix13.htm">Header
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Files for UNIX-Type Functions</a>)<br>
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<br>
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</li>
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<li><a href="sigaset.htm">sigaddset()</a>--Add Signal to Signal Set<br>
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<br>
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</li>
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<li><a href="sigdset.htm">sigdelset()</a>--Delete Signal from Signal Set<br>
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<br>
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</li>
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<li><a href="sigeset.htm">sigemptyset()</a>--Initialize and Empty Signal
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Set<br>
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<br>
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</li>
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<li><a href="sigfset.htm">sigfillset()</a>--Initialize and Fill Signal Set<br>
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<br>
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</li>
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<li><a href="sigismbr.htm">sigismember()</a>--Test for Signal in Signal Set<br>
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<br>
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</li>
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<li><a href="sigpmsk.htm">sigprocmask()</a>--Examine and Change Blocked
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Signals</li>
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</ul>
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<br>
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<h3>Example</h3>
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<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
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for information pertaining to code examples.</p>
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<p>The following example returns blocked and pending signals:</p>
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<pre>
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#include <signal.h>
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#include <unistd.h>
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#include <stdio.h>
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void catcher( int sig ) {
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puts( "inside catcher() function\n" );
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}
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void check_pending( int sig, char *signame ) {
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sigset_t sigset;
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if( sigpending( &sigset ) != 0 )
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perror( "sigpending() error\n" );
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else if( sigismember( &sigset, sig ) )
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printf( "a %s signal is pending\n", signame );
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else
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printf( "no %s signals are pending\n", signame );
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}
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int main( int argc, char *argv[] ) {
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struct sigaction sigact;
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sigset_t sigset;
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sigemptyset( &sigact.sa_mask );
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sigact.sa_flags = 0;
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sigact.sa_handler = catcher;
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if( sigaction( SIGUSR1, &sigact, NULL ) != 0 )
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perror( "sigaction() error\n" );
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else {
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sigemptyset( &sigset );
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sigaddset( &sigset, SIGUSR1 );
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if ( sigprocmask( SIG_SETMASK, &sigset, NULL ) != 0)
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perror( "sigprocmask() error\n" );
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else {
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printf( "SIGUSR1 signals are now blocked\n" );
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kill( getpid(), SIGUSR1 );
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printf( "after kill()\n" );
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check_pending( SIGUSR1, "SIGUSR1" );
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sigemptyset( &sigset );
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sigprocmask( SIG_SETMASK, &sigset, NULL );
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printf( "SIGUSR1 signals are no longer blocked\n" );
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check_pending( SIGUSR1, "SIGUSR1" );
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}
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}
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return( 0 );
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}
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</pre>
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<br>
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<h3>Output:</h3>
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<pre>
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SIGUSR1 signals are now blocked
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after kill()
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a SIGUSR1 signal is pending
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inside catcher() function
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SIGUSR1 signals are no longer blocked
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no SIGUSR1 signals are pending
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</pre>
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<br>
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<hr>
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API introduced: V3R6
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<hr>
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<center>
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<table cellpadding="2" cellspacing="2">
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<tr align="center">
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<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
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"unix.htm">UNIX-Type APIs</a> | <a href="aplist.htm">APIs by category</a></td>
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</tr>
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</table>
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</center>
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</body>
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</html>
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