NAME

sigemptyset, sigfillset, sigaddset, sigandset, sigdelset, sigisemptyset, sigismember, sigorset —

manipulate signal sets

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <signal.h>

int
sigemptyset(sigset_t *set);

int
sigfillset(sigset_t *set);

int
sigaddset(sigset_t *set, int signo);

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

int
sigdelset(sigset_t *set, int signo);

int
sigisemptyset(const sigset_t *set);

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

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

DESCRIPTION

These functions manipulate signal sets stored in a sigset_t. Either sigemptyset() or sigfillset() must be called for every object of type sigset_t before any other use of the object.

The sigemptyset() function initializes a signal set to be empty.

The sigfillset() function initializes a signal set to contain all signals.

The sigaddset() function adds the specified signal signo to the signal set.

The sigandset() function sets the specified set to the logical AND of all signals from the left and right signal sets.

The sigdelset() function deletes the specified signal signo from the signal set.

The sigisemptyset() function returns whether the specified set is empty or not.

The sigismember() function returns whether a specified signal signo is contained in the signal set.

The sigorset() function sets the specified set to the logical OR of all signals from the left and right signal sets.

RETURN VALUES

The sigisemptyset() function returns 1 if the set is empty, 0 otherwise.

The sigismember() function returns 1 if the signal is a member of the set, 0 otherwise.

The other functions return 0 upon success. A -1 return value indicates an error occurred and the global variable errno is set to indicate the reason.

ERRORS

These functions could fail if one of the following occurs:

[EINVAL]: signo has an invalid value.

STANDARDS

The sigandset(), sigisemptyset(), and sigorset() functions are FreeBSD extensions, compatible with functions of the same name provided by both musl libc and GNU libc.

The rest of these functions are defined by IEEE Std 1003.1-1988 (“POSIX.1”).