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 (con-
       sult 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(), sigsus-
       pend(), 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
       Signal Concepts, sigaction(), sigaddset(), sigdelset(), sigfillset(), sigemptyset(), sigpending(), sigprocmask(), sigsus-
       pend(), the Base Definitions volume of IEEE Std 1003.1-2001, <signal.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                               SIGISMEMBER(3P)