NAME

sigaddset — add a signal to a signal set

SYNOPSIS

#include <signal.h>

int sigaddset(sigset_t *set, int signo);

DESCRIPTION

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

Applications must call either sigemptyset() or sigfillset() at least once for each object of type sigset_t prior to any other use of that object. If such an object is not initialised in this way, but is nonetheless supplied as an argument to any of sigaction(), sigaddset(), sigdelset(), sigismember(), sigpending() or sigprocmask(), the results are undefined.

RETURN VALUE

Upon successful completion, sigaddset() returns 0. Otherwise, it returns -1 and sets errno to indicate the error.

ERRORS

The sigaddset() function may fail if:

[EINVAL]

The value of the signo argument is an invalid or unsupported signal number.

EXAMPLES

None.

APPLICATION USAGE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

sigaction(3) , sigdelset(3) , sigemptyset(3) , sigfillset(3) , sigismember(3) , sigpending(3) , sigprocmask(3) , sigsuspend(3) , <signal.h> .

DERIVATION

Derived from the POSIX.1-1988 standard.