MirBSD manpage: sigwait(3)

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

NAME

     sigwait - synchronously accept a signal

SYNOPSIS

     #include <signal.h>

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

DESCRIPTION

     The sigwait() function selects a pending signal from set, atomically
     clears it from the system's set of pending signals, and returns that sig-
     nal number in the location referenced by sig. If prior to the call to
     sigwait() there are multiple pending instances of a single signal number,
     it is undefined whether upon successful return there are any remaining
     pending signals for that signal number. If no signal in set is pending at
     the time of the call, the thread shall be suspended until one or more be-
     comes pending. The signals defined by set should have been blocked at the
     time of the call to sigwait(); otherwise the behaviour is undefined. The
     effect of sigwait() on the signal actions for the signals in set is un-
     specified.

     If more than one thread is using sigwait() to wait for the same signal,
     no more than one of these threads shall return from sigwait() with the
     signal number. Which thread returns from sigwait() if more than a single
     thread is waiting is unspecified.

     Note: Code using the sigwait() function must be compiled and linked with
     the -pthread option to gcc(1).

RETURN VALUES

     Upon successful completion, sigwait() stores the signal number of the re-
     ceived signal at the location referenced by sig and returns zero.

ERRORS

     On error, sigwait() returns one of these error values:

     [EINVAL]      The set argument contains an invalid or unsupported signal
                   number.

SEE ALSO

     sigaction(2), sigpending(2), sigsuspend(2), pause(3), pthread_sigmask(3),
     pthreads(3)

STANDARDS

     sigwait() conforms to ISO/IEC 9945-1:1996 ("POSIX.1").

MirBSD #10-current             August 20, 1998                               1