Merging upstream version 6.8.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 169 insertions, 0 deletions

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+.\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
+.\" and Copyright (c) 2004 by Michael Kerrisk <mtk.manpages@gmail.com>
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.\"
+.\" Modified Sat Jul 24 13:32:44 1993 by Rik Faith (faith@cs.unc.edu)
+.\" Modified Mon Jun 23 14:09:52 1997 by aeb - add EINTR.
+.\" Modified Tue Jul  7 12:26:42 1998 by aeb - changed return value wait3
+.\" Modified 2004-11-11, Michael Kerrisk <mtk.manpages@gmail.com>
+.\"	Rewrote much of this page, and removed much duplicated text,
+.\"		replacing with pointers to wait.2
+.\"
+.TH wait4 2 2024-05-02 "Linux man-pages (unreleased)"
+.SH NAME
+wait3, wait4 \- wait for process to change state, BSD style
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
+.SH SYNOPSIS
+.nf
+.B #include <sys/wait.h>
+.P
+.BI "pid_t wait3(int *_Nullable " "wstatus" ", int " options ,
+.BI "            struct rusage *_Nullable " rusage );
+.BI "pid_t wait4(pid_t " pid ", int *_Nullable " wstatus ", int " options ,
+.BI "            struct rusage *_Nullable " rusage );
+.fi
+.P
+.RS -4
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.RE
+.P
+.BR wait3 ():
+.nf
+    Since glibc 2.26:
+        _DEFAULT_SOURCE
+            || (_XOPEN_SOURCE >= 500 &&
+                ! (_POSIX_C_SOURCE >= 200112L
+                   || _XOPEN_SOURCE >= 600))
+    From glibc 2.19 to glibc 2.25:
+        _DEFAULT_SOURCE || _XOPEN_SOURCE >= 500
+    glibc 2.19 and earlier:
+        _BSD_SOURCE || _XOPEN_SOURCE >= 500
+.\"          || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
+.fi
+.P
+.BR wait4 ():
+.nf
+    Since glibc 2.19:
+        _DEFAULT_SOURCE
+    glibc 2.19 and earlier:
+        _BSD_SOURCE
+.fi
+.SH DESCRIPTION
+These functions are nonstandard; in new programs, the use of
+.BR waitpid (2)
+or
+.BR waitid (2)
+is preferable.
+.P
+The
+.BR wait3 ()
+and
+.BR wait4 ()
+system calls are similar to
+.BR waitpid (2),
+but additionally return resource usage information about the
+child in the structure pointed to by
+.IR rusage .
+.P
+Other than the use of the
+.I rusage
+argument, the following
+.BR wait3 ()
+call:
+.P
+.in +4n
+.EX
+wait3(wstatus, options, rusage);
+.EE
+.in
+.P
+is equivalent to:
+.P
+.in +4n
+.EX
+waitpid(\-1, wstatus, options);
+.EE
+.in
+.P
+Similarly, the following
+.BR wait4 ()
+call:
+.P
+.in +4n
+.EX
+wait4(pid, wstatus, options, rusage);
+.EE
+.in
+.P
+is equivalent to:
+.P
+.in +4n
+.EX
+waitpid(pid, wstatus, options);
+.EE
+.in
+.P
+In other words,
+.BR wait3 ()
+waits of any child, while
+.BR wait4 ()
+can be used to select a specific child, or children, on which to wait.
+See
+.BR wait (2)
+for further details.
+.P
+If
+.I rusage
+is not NULL, the
+.I struct rusage
+to which it points will be filled with accounting information
+about the child.
+See
+.BR getrusage (2)
+for details.
+.SH RETURN VALUE
+As for
+.BR waitpid (2).
+.SH ERRORS
+As for
+.BR waitpid (2).
+.SH STANDARDS
+None.
+.SH HISTORY
+4.3BSD.
+.P
+SUSv1 included a specification of
+.BR wait3 ();
+SUSv2 included
+.BR wait3 (),
+but marked it LEGACY;
+SUSv3 removed it.
+.P
+Including
+.I <sys/time.h>
+is not required these days, but increases portability.
+(Indeed,
+.I <sys/resource.h>
+defines the
+.I rusage
+structure with fields of type
+.I struct timeval
+defined in
+.IR <sys/time.h> .)
+.SS C library/kernel differences
+On Linux,
+.BR wait3 ()
+is a library function implemented on top of the
+.BR wait4 ()
+system call.
+.SH SEE ALSO
+.BR fork (2),
+.BR getrusage (2),
+.BR sigaction (2),
+.BR signal (2),
+.BR wait (2),
+.BR signal (7)