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SIGSETOPS(3)		     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 con-
     tained 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 ex-
     tensions, 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 15.1			October 29, 2019		    SIGSETOPS(3)
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