SIGISMEMBER(3P)            POSIX Programmer's Manual           SIGISMEMBER(3P)

PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the corresponding
       Linux manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.

NAME
       sigismember -- test for a signal in a signal set

SYNOPSIS
       #include <signal.h>

       int sigismember(const sigset_t *set, int signo);

DESCRIPTION
       The sigismember() function shall test whether the signal specified by
       signo is a member of the set pointed to by set.

       Applications should call either sigemptyset() or sigfillset() at least
       once for each object of type sigset_t prior to any other use of that
       object. If such an object is not initialized in this way, but is
       nonetheless supplied as an argument to any of pthread_sigmask(),
       sigaction(), sigaddset(), sigdelset(), sigismember(), sigpending(),
       sigprocmask(), sigsuspend(), sigtimedwait(), sigwait(), or
       sigwaitinfo(), the results are undefined.

RETURN VALUE
       Upon successful completion, sigismember() shall return 1 if the
       specified signal is a member of the specified set, or 0 if it is not.
       Otherwise, it shall return -1 and set errno to indicate the error.

ERRORS
       The sigismember() function may fail if:

       EINVAL The signo argument is not a valid signal number, or is an
              unsupported signal number.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Section 2.4, Signal Concepts, pthread_sigmask(), sigaction(),
       sigaddset(), sigdelset(), sigfillset(), sigemptyset(), sigpending(),
       sigsuspend()

       The Base Definitions volume of POSIX.1-2017, <signal.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                  2017                      SIGISMEMBER(3P)