SIGSETOPS(3) | Library Functions Manual | SIGSETOPS(3)

# NAME

`sigemptyset`, `sigfillset`, `sigaddset`, `sigdelset`, `sigismember` —
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
`sigdelset`(sigset_t *set, int signo);

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

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

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

`sigemptyset`() and `sigfillset`() are provided as macros, but actual functions are available if their names are undefined (with #undef name).

# RETURN VALUES

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

# SEE ALSO

kill(2), sigaction(2), sigsuspend(2), signal(7)

# STANDARDS

These functions conform to IEEE Std 1003.1-1990 (“POSIX.1”).

June 4, 1993 | NetBSD 9.5