Manpages - sigsetops.3
Table of Contents
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
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 *sigorset*()). 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 error.
ERRORS
- EINVAL
- signum is not a valid signal.
ATTRIBUTES
For an explanation of the terms used in this section, see *attributes*(7).
| Interface | Attribute | Value |
| *sigemptyset*(), *sigfillset*(), *sigaddset*(), *sigdelset*(), *sigismember*(), *sigisemptyset*(), *sigorset*(), *sigandset*() | Thread safety | MT-Safe |
CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
NOTES
When creating a filled signal set, the glibc *sigfillset*() function does not include the two real-time signals used internally by the NPTL threading implementation. See *nptl*(7) for details.
Glibc extensions
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
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