NAME

       sigwait - wait for a signal

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #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

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).

SEE ALSO

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