NAME

sigismember - test for a signal in a signal set

SYNOPSIS

[CX] #include <signal.h>

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

DESCRIPTION

The sigismember() function shall test whether the signal specified by signo is a member of the set pointed to by set.

Applications should 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 initialized in this way, but is nonetheless supplied as an argument to any of pthread_sigmask(), sigaction(), sigaddset(), sigdelset(), sigismember(), sigpending(), sigprocmask(), sigsuspend(), sigtimedwait(), sigwait(), or sigwaitinfo(), the results are undefined.

RETURN VALUE

Upon successful completion, sigismember() shall return 1 if the specified signal is a member of the specified set, or 0 if it is not. Otherwise, it shall return -1 and set errno to indicate the error.

ERRORS

The sigismember() function may fail if:

[EINVAL]

The signo argument is not a valid signal number, or is an unsupported signal number.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

Signal Concepts , sigaction() , sigaddset() , sigdelset() , sigfillset() , sigemptyset() , sigpending() , sigprocmask() , sigsuspend() , the Base Definitions volume of IEEE Std 1003.1-2001, <signal.h>

CHANGE HISTORY

First released in Issue 3. Included for alignment with the POSIX.1-1988 standard.

Issue 5

The last paragraph of the DESCRIPTION was included as an APPLICATION USAGE note in previous issues.

Issue 6

The SYNOPSIS is marked CX since the presence of this function in the <signal.h> header is an extension over the ISO C standard.