NAME

     sigprocmask - manipulate the signal mask


SYNOPSIS

     #include <signal.h>

     int  sigprocmask(int  how,  const  sigset_t  *set,  sigset_t
     *oset)


DESCRIPTION

     Sigprocmask() examines or manipulates the signal mask.  This
     mask  is the set of signals that are currently blocked.  The
     how argument determines the action that must  be  performed.
     In all cases the signal set referenced by oset, if not NULL,
     will be used to receive the old signal mask.  The set  argu-
     ment, if not NULL, will be used to set or modify the current
     signal mask.

     How can be one of:

     SIG_BLOCK      Add the signals  referenced  by  set  to  the
                    mask.

     SIG_UNBLOCK    Remove the signals referenced by set from the
                    mask.

     SIG_SETMASK    Set the signal mask to the set referenced  by
                    set.

     The value of how is ignored if set is NULL.


SEE ALSO

     sigaction(2), sigpending(2), sigsuspend(2), sigset(3).


DIAGNOSTICS

     Returns 0 on success and -1 on error.   The  error  code  is
     EFAULT  for  a  bad set or oset address, or EINVAL for a bad
     how argument.


AUTHOR

     Kees J. Bot (kjb@cs.vu.nl)