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



NAME
       sigemptyset, sigfillset, sigaddset, sigdelset, sigismember - POSIX signal set operations

SYNOPSIS
       #include <signal.h>

       int sigemptyset(sigset_t *set);

       int sigfillset(sigset_t *set);

       int sigaddset(sigset_t *set, int signum);

       int sigdelset(sigset_t *set, int signum);

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

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       sigemptyset(), sigfillset(), sigaddset(), sigdelset(), sigismember():
           _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_SOURCE

DESCRIPTION
       These functions allow the manipulation of POSIX signal sets.

       sigemptyset()  initializes the signal set given by set to empty, with all signals excluded
       from the set.

       sigfillset() initializes set to full, including all signals.

       sigaddset() and sigdelset() add and delete respectively signal signum from set.

       sigismember() tests whether signum is a member of set.

       Objects of type sigset_t must be initialized by a call to  either  sigemptyset()  or  sig‐
       fillset()  before being passed to the functions sigaddset(), sigdelset() and sigismember()
       or the additional glibc functions described below (sigisemptyset(), sigandset(), and  sig‐
       orset()).  The results are undefined if this is not done.

RETURN VALUE
       sigemptyset(),  sigfillset(),  sigaddset(),  and sigdelset() return 0 on success and -1 on
       error.

       sigismember() returns 1 if signum is a member of set, 0 if signum is not a member, and  -1
       on error.  On error, these functions set errno to indicate the cause.

ERRORS
       EINVAL sig is not a valid signal.

ATTRIBUTES
   Multithreading (see pthreads(7))
       The sigemptyset(), sigfillset(), sigaddset(), sigdelset(), sigismember(), sigisemptyset(),
       sigorset(), and sigandset() functions are thread-safe.

CONFORMING TO
       POSIX.1-2001.

NOTES
   Glibc notes
       If the _GNU_SOURCE feature test macro is defined,  then  <signal.h>  exposes  three  other
       functions for manipulating signal sets:

       int sigisemptyset(const sigset_t *set);
       int sigorset(sigset_t *dest, const sigset_t *left,
                     const sigset_t *right);
       int sigandset(sigset_t *dest, const sigset_t *left,
                     const sigset_t *right);

       sigisemptyset() returns 1 if set contains no signals, and 0 otherwise.

       sigorset()  places  the  union of the sets left and right in dest.  sigandset() places the
       intersection of the sets left and right in dest.  Both functions return 0 on success,  and
       -1 on failure.

       These  functions are nonstandard (a few other systems provide similar functions) and their
       use should be avoided in portable applications.

SEE ALSO
       sigaction(2), sigpending(2), sigprocmask(2), sigsuspend(2)

COLOPHON
       This page is part of release 3.74 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 http://www.kernel.org/doc/man-pages/.



Linux                                       2014-04-14                               SIGSETOPS(3)