getent.1, intro.1, time.1, _exit.2, _syscall.2, accept.2, access.2, acct.2, adjtimex...

[thirdparty/man-pages.git] / man3 / sigpause.3

.\" Copyright (C) 2004 Andries Brouwer (aeb@cwi.nl)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.TH SIGPAUSE 3 2010-09-12 "Linux" "Linux Programmer's Manual"
.SH NAME
sigpause \- atomically release blocked signals and wait for interrupt
.SH SYNOPSIS
.nf
.B #include <signal.h>
.sp
.BI "int sigpause(int " sigmask ");  /* BSD */"
.sp
.BI "int sigpause(int " sig ");      /* System V / UNIX 95 */"
.fi
.SH DESCRIPTION
Don't use this function.
Use
.BR sigsuspend (2)
instead.
.LP
The function
.BR sigpause ()
is designed to wait for some signal.
It changes the process's signal mask (set of blocked signals),
and then waits for a signal to arrive.
Upon arrival of a signal, the original signal mask is restored.
.SH RETURN VALUE
If
.BR sigpause ()
returns, it was interrupted by a signal and the return value is \-1
with
.I errno
set to
.BR EINTR .
.SH CONFORMING TO
The System V version of
.BR sigpause ()
is standardized in POSIX.1-2001.
.SH NOTES
.SS History
The classical BSD version of this function appeared in 4.2BSD.
It sets the process's signal mask to
.IR sigmask .
UNIX 95 standardized the incompatible System V version of
this function, which removes only the specified signal
.I sig
from the process's signal mask.
.\" __xpg_sigpause: UNIX 95, spec 1170, SVID, SVr4, XPG
The unfortunate situation with two incompatible functions with the
same name was solved by the
.BR \%sigsuspend (2)
function, that takes a
.I "sigset_t *"
argument (instead of an
.IR int ).
.SS Linux notes
On Linux, this routine is a system call only on the Sparc (sparc64)
architecture.

Libc4 and libc5 only know about the BSD version.

Glibc uses the BSD version if the
.B _BSD_SOURCE
feature test macro is defined and none of
.BR _POSIX_SOURCE ,
.BR _POSIX_C_SOURCE ,
.BR _XOPEN_SOURCE ,
.BR _GNU_SOURCE ,
or
.B _SVID_SOURCE
is defined.
Otherwise, the System V version is used.
.\"
.\" For the BSD version, one usually uses a zero
.\" .I sigmask
.\" to indicate that no signals are to be blocked.
.SH SEE ALSO
.BR kill (2),
.BR sigaction (2),
.BR sigprocmask (2),
.BR sigsuspend (2),
.BR sigblock (3),
.BR sigvec (3),
.BR feature_test_macros (7)