NAME
sigaddset — add a
signal to a signal set
SYNOPSIS
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 shall 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 (), sigdelset(3),
sigismember(3), sigpending(3),
sigprocmask(3), sigsuspend(3),
sigtimedwait(3), sigwait(3), or
sigwaitinfo(3), the results are undefined.
RETURN VALUE
Upon successful completion, sigaddset ()
shall return 0; otherwise, it shall return -1 and set
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.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
xsh_chap02_04(3), sigaction(3), sigdelset(3), sigemptyset(3), sigfillset(3), sigismember(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 DESCRIPTION is updated to avoid use of the term "must" for application requirements.
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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