SIGSETOPS(3)           FreeBSD Library Functions Manual           SIGSETOPS(3)

NAME
     sigemptyset, sigfillset, sigaddset, sigandset, sigdelset, sigisemptyset,
     sigismember, sigorset - manipulate signal sets

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <signal.h>

     int
     sigemptyset(sigset_t *set);

     int
     sigfillset(sigset_t *set);

     int
     sigaddset(sigset_t *set, int signo);

     int
     sigandset(sigset_t *set, const sigset_t *left, const sigset_t *right);

     int
     sigdelset(sigset_t *set, int signo);

     int
     sigisemptyset(const sigset_t *set);

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

     int
     sigorset(sigset_t *set, const sigset_t *left, const sigset_t *right);

DESCRIPTION
     These functions manipulate signal sets stored in a sigset_t.  Either
     sigemptyset() or sigfillset() must be called for every object of type
     sigset_t before any other use of the object.

     The sigemptyset() function initializes a signal set to be empty.

     The sigfillset() function initializes a signal set to contain all
     signals.

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

     The sigandset() function sets the specified set to the logical AND of all
     signals from the left and right signal sets.

     The sigdelset() function deletes the specified signal signo from the
     signal set.

     The sigisemptyset() function returns whether the specified set is empty
     or not.

     The sigismember() function returns whether a specified signal signo is
     contained in the signal set.

     The sigorset() function sets the specified set to the logical OR of all
     signals from the left and right signal sets.

RETURN VALUES
     The sigisemptyset() function returns 1 if the set is empty, 0 otherwise.

     The sigismember() function returns 1 if the signal is a member of the
     set, 0 otherwise.

     The other functions return 0 upon success.  A -1 return value indicates
     an error occurred and the global variable errno is set to indicate the
     reason.

ERRORS
     These functions could fail if one of the following occurs:

     [EINVAL]           signo has an invalid value.

SEE ALSO
     kill(2), sigaction(2), sigpending(2), sigprocmask(2), sigsuspend(2)

STANDARDS
     The sigandset(), sigisemptyset(), and sigorset() functions are FreeBSD
     extensions, compatible with functions of the same name provided by both
     musl libc and GNU libc.

     The rest of these functions are defined by IEEE Std 1003.1-1988
     ("POSIX.1").

FreeBSD 13.1-RELEASE-p6        October 29, 2019        FreeBSD 13.1-RELEASE-p6