sigwait(3) [x11r4 man page]

SIGWAIT(3)						     Linux Programmer's Manual							SIGWAIT(3)

NAME

       sigwait - wait for a signal

SYNOPSIS

       #include <signal.h>

	int sigwait(const sigset_t *set, int *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.
       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 |
       +----------+---------------+---------+
CONFORMING TO

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

NOTES

       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.

EXAMPLE

       See pthread_sigmask(3).

SEE ALSO

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

COLOPHON

       This  page is part of release 4.15 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								    2017-07-13								SIGWAIT(3)

SIGWAIT(2)						      BSD System Calls Manual							SIGWAIT(2)

NAME

     sigwait -- select a set of signals

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <signal.h>

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

DESCRIPTION

     The sigwait() system call selects a set of signals, specified by set.  If none of the selected signals are pending, sigwait() waits until one
     or more of the selected signals has been generated.  Then sigwait() atomically clears one of the selected signals from the set of pending
     signals (for the process or for the current thread) and sets the location pointed to by sig to the signal number that was cleared.

     The signals specified by set should be blocked at the time of the call to sigwait().

     If more than one thread is using sigwait() to wait for the same signal, no more than one of these threads will return from sigwait() with the
     signal number.  If more than a single thread is blocked in sigwait() for a signal when that signal is generated for the process, it is
     unspecified which of the waiting threads returns from sigwait().  If the signal is generated for a specific thread, as by pthread_kill(),
     only that thread will return.

     Should any of the multiple pending signals in the range SIGRTMIN to SIGRTMAX be selected, it will be the lowest numbered one.  The selection
     order between realtime and non-realtime signals, or between multiple pending non-realtime signals, is unspecified.

IMPLEMENTATION NOTES

     The sigwait() function is implemented as a wrapper around the __sys_sigwait() system call, which retries the call on EINTR error.

RETURN VALUES

     If successful, sigwait() returns 0 and sets the location pointed to by sig to the cleared signal number.  Otherwise, an error number is
     returned.

ERRORS

     The sigwait() system call will fail if:

     [EINVAL]		The set argument specifies one or more invalid signal numbers.

SEE ALSO

     sigaction(2), sigpending(2), sigqueue(2), sigsuspend(2), sigtimedwait(2), sigwaitinfo(2), pause(3), pthread_sigmask(3)

STANDARDS

     The sigwait() function conforms to ISO/IEC 9945-1:1996 (``POSIX.1'').

BSD
								 September 6, 2013							       BSD