These functions manipulate sigset_t data types, representing the set of signals supported by the implementation.

The sigemptyset() function initializes the set pointed to by set to exclude all signals defined by the system.

The sigfillset() function initializes the set pointed to by set to include all signals defined by the system.

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

The sigdelset() function deletes the individual signal specified by the value of signo from the set pointed to by set.

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

Any object of type sigset_t must be initialized by applying either sigemptyset() or sigfillset() before applying any other operation.

Upon successful completion, the sigismember() function returns 1 if the specified signal is a member of the specified set, or 0 if it is not.

Upon successful completion, the other functions return 0. Otherwise -1 is returned and errno is set to indicate the error.

The sigaddset(), sigdelset(), and sigismember() functions will fail if:

EINVAL

The value of the signo argument is not a valid signal number.

The sigfillset() function will fail if:

EFAULT

The set argument specifies an invalid address.

See attributes(5) for descriptions of the following attributes:

sigaction(2), sigpending(2), sigprocmask(2), sigsuspend(2), attributes(5), signal(3HEAD)