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wait4.html
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<!-- Creator : groff version 1.22.4 -->
<!-- CreationDate: Wed Jan 29 11:26:18 2020 -->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<meta name="Content-Style" content="text/css">
<style type="text/css">
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<title>WAIT4</title>
</head>
<body>
<h1 align="center">WAIT4</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#RETURN VALUE">RETURN VALUE</a><br>
<a href="#ERRORS">ERRORS</a><br>
<a href="#CONFORMING TO">CONFORMING TO</a><br>
<a href="#NOTES">NOTES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<a href="#COLOPHON">COLOPHON</a><br>
<hr>
<h2>NAME
<a name="NAME"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">wait3, wait4 -
wait for process to change state, BSD style</p>
<h2>SYNOPSIS
<a name="SYNOPSIS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<sys/types.h> <br>
#include <sys/time.h> <br>
#include <sys/resource.h> <br>
#include <sys/wait.h></b></p>
<p style="margin-left:11%; margin-top: 1em"><b>pid_t
wait3(int *</b><i>wstatus</i><b>, int</b> <i>options</i><b>,
<br>
struct rusage *</b><i>rusage</i><b>);</b></p>
<p style="margin-left:11%; margin-top: 1em"><b>pid_t
wait4(pid_t</b> <i>pid</i><b>, int *</b><i>wstatus</i><b>,
int</b> <i>options</i><b>, <br>
struct rusage *</b><i>rusage</i><b>);</b></p>
<p style="margin-left:5%; margin-top: 1em">Feature Test
Macro Requirements for glibc (see
<b>feature_test_macros</b>(7)):</p>
<p style="margin-left:11%; margin-top: 1em"><b>wait3</b>():
<br>
Since glibc 2.19: <br>
_DEFAULT_SOURCE || _XOPEN_SOURCE >= 500 <br>
Glibc 2.19 and earlier: <br>
_BSD_SOURCE || _XOPEN_SOURCE >= 500 <b><br>
wait4</b>(): <br>
Since glibc 2.19: <br>
_DEFAULT_SOURCE <br>
Glibc 2.19 and earlier: <br>
_BSD_SOURCE</p>
<h2>DESCRIPTION
<a name="DESCRIPTION"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">These functions
are nonstandard; in new programs, the use of
<b>waitpid</b>(2) or <b>waitid</b>(2) is preferable.</p>
<p style="margin-left:11%; margin-top: 1em">The
<b>wait3</b>() and <b>wait4</b>() system calls are similar
to <b>waitpid</b>(2), but additionally return resource usage
information about the child in the structure pointed to by
<i>rusage</i>.</p>
<p style="margin-left:11%; margin-top: 1em">Other than the
use of the <i>rusage</i> argument, the following
<b>wait3</b>() call:</p>
<p style="margin-left:17%; margin-top: 1em">wait3(wstatus,
options, rusage);</p>
<p style="margin-left:11%; margin-top: 1em">is equivalent
to:</p>
<p style="margin-left:17%; margin-top: 1em">waitpid(-1,
wstatus, options);</p>
<p style="margin-left:11%; margin-top: 1em">Similarly, the
following <b>wait4</b>() call:</p>
<p style="margin-left:17%; margin-top: 1em">wait4(pid,
wstatus, options, rusage);</p>
<p style="margin-left:11%; margin-top: 1em">is equivalent
to:</p>
<p style="margin-left:17%; margin-top: 1em">waitpid(pid,
wstatus, options);</p>
<p style="margin-left:11%; margin-top: 1em">In other words,
<b>wait3</b>() waits of any child, while <b>wait4</b>() can
be used to select a specific child, or children, on which to
wait. See <b>wait</b>(2) for further details.</p>
<p style="margin-left:11%; margin-top: 1em">If
<i>rusage</i> is not NULL, the <i>struct rusage</i> to which
it points will be filled with accounting information about
the child. See <b>getrusage</b>(2) for details.</p>
<h2>RETURN VALUE
<a name="RETURN VALUE"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">As for
<b>waitpid</b>(2).</p>
<h2>ERRORS
<a name="ERRORS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">As for
<b>waitpid</b>(2).</p>
<h2>CONFORMING TO
<a name="CONFORMING TO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">4.3BSD.</p>
<p style="margin-left:11%; margin-top: 1em">SUSv1 included
a specification of <b>wait3</b>(); SUSv2 included
<b>wait3</b>(), but marked it LEGACY; SUSv3 removed it.</p>
<h2>NOTES
<a name="NOTES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">Including
<i><sys/time.h></i> is not required these days, but
increases portability. (Indeed,
<i><sys/resource.h></i> defines the <i>rusage</i>
structure with fields of type <i>struct timeval</i> defined
in <i><sys/time.h></i>.)</p>
<p style="margin-left:11%; margin-top: 1em"><b>C
library/kernel differences</b> <br>
On Linux, <b>wait3</b>() is a library function implemented
on top of the <b>wait4</b>() system call.</p>
<h2>SEE ALSO
<a name="SEE ALSO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>fork</b>(2),
<b>getrusage</b>(2), <b>sigaction</b>(2), <b>signal</b>(2),
<b>wait</b>(2), <b>signal</b>(7)</p>
<h2>COLOPHON
<a name="COLOPHON"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">This page is
part of release 5.02 of the Linux <i>man-pages</i> project.
A description of the project, information about reporting
bugs, and the latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.</p>
<hr>
</body>
</html>