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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
SIGSUSPEND(2) Linux Programmer's Manual SIGSUSPEND(2)
sigsuspend, rt_sigsuspend - wait for a signal
#include <signal.h>
int sigsuspend(const sigset_t *mask);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
sigsuspend(): _POSIX_C_SOURCE
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.
sigsuspend() always returns -1, with errno set to indicate the error
(normally, EINTR).
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).
POSIX.1-2001, POSIX.1-2008.
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.
kill(2), pause(2), sigaction(2), signal(2), sigprocmask(2),
sigwaitinfo(2), sigsetops(3), sigwait(3), signal(7)
This page is part of release 4.12 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/.
Linux 2016-03-15 SIGSUSPEND(2)
Pages that refer to this page: pause(2), sigaction(2), signal(2), sigpending(2), sigprocmask(2), syscalls(2), sigpause(3), sigset(3), sigsetops(3), sigwait(3), signal(7), signal-safety(7)