-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathBSD-Wait-Functions.html
More file actions
110 lines (92 loc) · 4.97 KB
/
BSD-Wait-Functions.html
File metadata and controls
110 lines (92 loc) · 4.97 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
<html lang="en">
<head>
<title>BSD Wait Functions - The GNU C Library</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="The GNU C Library">
<meta name="generator" content="makeinfo 4.9">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Processes.html#Processes" title="Processes">
<link rel="prev" href="Process-Completion-Status.html#Process-Completion-Status" title="Process Completion Status">
<link rel="next" href="Process-Creation-Example.html#Process-Creation-Example" title="Process Creation Example">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
This file documents the GNU C library.
This is Edition 0.11, last updated 2007-09-09,
of `The GNU C Library Reference Manual', for version 2.7.
Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002,
2003, 2007 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Free Software Needs Free Documentation''
and ``GNU Lesser General Public License'', the Front-Cover texts being
``A GNU Manual'', and with the Back-Cover Texts as in (a) below. A
copy of the license is included in the section entitled "GNU Free
Documentation License".
(a) The FSF's Back-Cover Text is: ``You are free to copy and modify
this GNU Manual. Buying copies from GNU Press supports the FSF in
developing GNU and promoting software freedom.''-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<p>
<a name="BSD-Wait-Functions"></a>
Next: <a rel="next" accesskey="n" href="Process-Creation-Example.html#Process-Creation-Example">Process Creation Example</a>,
Previous: <a rel="previous" accesskey="p" href="Process-Completion-Status.html#Process-Completion-Status">Process Completion Status</a>,
Up: <a rel="up" accesskey="u" href="Processes.html#Processes">Processes</a>
<hr>
</div>
<h3 class="section">26.8 BSD Process Wait Functions</h3>
<p>The GNU library also provides these related facilities for compatibility
with BSD Unix. BSD uses the <code>union wait</code> data type to represent
status values rather than an <code>int</code>. The two representations are
actually interchangeable; they describe the same bit patterns. The GNU
C Library defines macros such as <code>WEXITSTATUS</code> so that they will
work on either kind of object, and the <code>wait</code> function is defined
to accept either type of pointer as its <var>status-ptr</var> argument.
<p>These functions are declared in <samp><span class="file">sys/wait.h</span></samp>.
<a name="index-sys_002fwait_002eh-3192"></a>
<!-- sys/wait.h -->
<!-- BSD -->
<div class="defun">
— Data Type: <b>union wait</b><var><a name="index-union-wait-3193"></a></var><br>
<blockquote><p>This data type represents program termination status values. It has
the following members:
<dl>
<dt><code>int w_termsig</code><dd>The value of this member is the same as that of the
<code>WTERMSIG</code> macro.
<br><dt><code>int w_coredump</code><dd>The value of this member is the same as that of the
<code>WCOREDUMP</code> macro.
<br><dt><code>int w_retcode</code><dd>The value of this member is the same as that of the
<code>WEXITSTATUS</code> macro.
<br><dt><code>int w_stopsig</code><dd>The value of this member is the same as that of the
<code>WSTOPSIG</code> macro.
</dl>
<p>Instead of accessing these members directly, you should use the
equivalent macros.
</p></blockquote></div>
<p>The <code>wait3</code> function is the predecessor to <code>wait4</code>, which is
more flexible. <code>wait3</code> is now obsolete.
<!-- sys/wait.h -->
<!-- BSD -->
<div class="defun">
— Function: pid_t <b>wait3</b> (<var>union wait *status-ptr, int options, struct rusage *usage</var>)<var><a name="index-wait3-3194"></a></var><br>
<blockquote><p>If <var>usage</var> is a null pointer, <code>wait3</code> is equivalent to
<code>waitpid (-1, </code><var>status-ptr</var><code>, </code><var>options</var><code>)</code>.
<p>If <var>usage</var> is not null, <code>wait3</code> stores usage figures for the
child process in <code>*</code><var>rusage</var> (but only if the child has
terminated, not if it has stopped). See <a href="Resource-Usage.html#Resource-Usage">Resource Usage</a>.
</p></blockquote></div>
</body></html>