NAME
sigismember — test
for a signal in a signal set
SYNOPSIS
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(3) or sigfillset(3) 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(3), sigaction(3),
sigaddset(3), sigdelset(3),
sigismember (), sigpending(3),
sigprocmask(3), sigsuspend(3),
sigtimedwait(3), sigwait(3), or
sigwaitinfo(3), 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
xsh_chap02_04(3), sigaction(3), sigaddset(3), sigdelset(3), sigfillset(3), sigemptyset(3), sigpending(3), sigprocmask(3), sigsuspend(3), the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <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.
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