sigwait — wait for a signal


#include <signal.h>

 int sigwait(const sigset_t *set, int *sig);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):


Since glibc 2.26:
   _POSIX_C_SOURCE >= 199506L
Glibc 2.25 and earlier:


The sigwait() function suspends execution of the calling thread until one of the signals specified in the signal set set becomes pending. The function accepts the signal (removes it from the pending list of signals), and returns the signal number in sig.

The operation of sigwait() is the same as sigwaitinfo(2), except that:

Return Value

On success, sigwait() returns 0. On error, it returns a positive error number (listed in Errors).



set contains an invalid signal number.


For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
sigwait() Thread safety MT-Safe

Conforming to

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


sigwait() is implemented using sigtimedwait(2).

The glibc implementation of sigwait() silently ignores attempts to wait for the two real-time signals that are used internally by the NPTL threading implementation. See nptl(7) for details.


See pthread_sigmask(3).

See Also

sigaction(2), signalfd(2), sigpending(2), sigsuspend(2), sigwaitinfo(2), sigsetops(3), signal(7)


This page is part of release 5.04 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

Referenced By

kill(2), nptl(7), pthread_sigmask(3), pthread_sigqueue(3), pthsem(3), signal(7), signalfd(2), sigqueue(3), sigsuspend(2), sigwaitinfo(2).

2017-07-13 Linux Programmer's Manual