sigwait

(3)

wait for a signal

#include <signal.h> int sigwait(const sigset_t *restrict set, int *restrict sig); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): sigwait(): Since glibc 2.26: _POSIX_C_SOURCE >= 199506L glibc 2.25 and earlier: _POSIX_C_SOURCE

LIBRARY

Standard C library (libc, -lc)

DESCRIPTION

The sigwait() function suspends execution of the calling thread until one of the signals specified in the signal set set becomes pending. For a signal to become pending, it must first be blocked with sigprocmask(2). 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:

•: sigwait() returns only the signal number, rather than a siginfo_t structure describing the signal.
•: The return values of the two functions are different.

RETURN VALUE

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

ERRORS

EINVAL: set contains an invalid signal number.

ATTRIBUTES

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

Interface	Attribute	Value
sigwait ()	Thread safety	MT-Safe

VERSIONS

sigwait() is implemented using sigtimedwait(2); consult its NOTES.

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.

STANDARDS

POSIX.1-2008.

HISTORY

POSIX.1-2001.

EXAMPLES

See pthread_sigmask(3).