SIGSETOPS(3)              386BSD Programmer's Manual              SIGSETOPS(3)

NAME
     sigsetops, sigemptyset, sigfillset, sigaddset, sigdelset, sigismember -
     manipulate signal masks

SYNOPSIS
     #include <signal.h>

     sigemptyset(sigset_t *set)

     sigfillset(sigset_t *set)

     sigaddset(sigset_t *set, int signo)

     sigdelset(sigset_t *set, int signo)

     sigismember(sigset_t *set, int signo)

DESCRIPTION
     These functions manipulate signal mask stored in a sigset_t.

     The sigemptyset() function initializes a signal set to be empty.  The
     sigfillset() function initializes a signal set to contain all of the
     known signals.  One of these routines must be used to initialize a signal
     set before its use by the other functions.

     The sigaddset() function adds a specified signal signo to a signal set.
     The sigdelset() function deletes a specified signal signo from a signal
     set.

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

RETURN VALUES
     The sigismember() function returns 1 if the signal is a member of the
     set, a 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 indicated the reason.  The current implementation does not detect
     any errors.

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

     [EINVAL]  signo has an invalid value.

SEE ALSO
     kill(2),  sigaction(2),  sigsetops(2),  sigsuspend(2)

STANDARDS
     These functions are defined by IEEE Std1003.1-1988 (``POSIX'').

BSD Experimental                April 19, 1991                               1