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);

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 sigfillset() before being passed to the functions sigaddset(), sigdelset() and sigismember() or the additional glibc functions described below (sigisemptyset(), sigandset(), and sigdelset()). 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.

ERRORS

EINVAL

sig is not a valid signal.

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(sigset_t *set);

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

int sigorset(sigset_t *dest, sigset_t *left, sigset_t *right);

places the union of the sets left and right in dest.

int sigandset(sigset_t *dest, sigset_t *left, sigset_t *right);

places the intersection of the sets left and right in dest.

sigorset() and sigandset() return 0 on success, and −1 on failure.

These functions are non-standard (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 2.79 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


  Copyright (c) 1994 Mike Battersby

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Modified by aeb, 960721
2005-11-21, mtk, added descriptions of sigisemptyset(), sigandset(),
                 and sigorset()
2007-10-26 mdw   added wording that a sigset_t must be initialized
                 prior to use