Name

sigsuspend, rt_sigsuspend — wait for a signal

Synopsis

        #include <signal.h>
int sigsuspend( const sigset_t *mask);
 
[Note] Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sigsuspend():
_POSIX_C_SOURCE

DESCRIPTION

sigsuspend() temporarily replaces the signal mask of the calling process with the mask given by mask and then suspends the process until delivery of a signal whose action is to invoke a signal handler or to terminate a process.

If the signal terminates the process, then sigsuspend() does not return. If the signal is caught, then sigsuspend() returns after the signal handler returns, and the signal mask is restored to the state before the call to sigsuspend().

It is not possible to block SIGKILL or SIGSTOP; specifying these signals in mask, has no effect on the process's signal mask.

RETURN VALUE

sigsuspend() always returns −1, with errno set to indicate the error (normally, EINTR).

ERRORS

EFAULT

mask points to memory which is not a valid part of the process address space.

EINTR

The call was interrupted by a signal; signal(7).

CONFORMING TO

POSIX.1-2001, POSIX.1-2008.

NOTES

Normally, sigsuspend() is used in conjunction with sigprocmask(2) in order to prevent delivery of a signal during the execution of a critical code section. The caller first blocks the signals with sigprocmask(2). When the critical code has completed, the caller then waits for the signals by calling sigsuspend() with the signal mask that was returned by sigprocmask(2) (in the oldset argument).

See sigsetops(3) for details on manipulating signal sets.

C library/kernel differences

The original Linux system call was named sigsuspend(). However, with the addition of real-time signals in Linux 2.2, the fixed-size, 32-bit sigset_t type supported by that system call was no longer fit for purpose. Consequently, a new system call, rt_sigsuspend(), was added to support an enlarged sigset_t type. The new system call takes a second argument, size_t sigsetsize, which specifies the size in bytes of the signal set in mask. This argument is currently required to have the value sizeof(sigset_t) (or the error EINVAL results). The glibc sigsuspend() wrapper function hides these details from us, transparently calling rt_sigsuspend() when the kernel provides it.

SEE ALSO

kill(2), pause(2), sigaction(2), signal(2), sigprocmask(2), sigwaitinfo(2), sigsetops(3), sigwait(3), signal(7)

COLOPHON

This page is part of release 4.07 of the Linux man-pages 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/.


  Copyright (c) 2005 Michael Kerrisk
based on earlier work by faithcs.unc.edu and
Mike Battersby <mibdeakin.edu.au>

%%%LICENSE_START(VERBATIM)
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.
%%%LICENSE_END

2005-09-15, mtk, Created new page by splitting off from sigaction.2