NAME    [Toc]    [Back]

     sigprocmask - manipulate current signal mask

SYNOPSIS    [Toc]    [Back]

     #include <signal.h>

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

DESCRIPTION    [Toc]    [Back]

     The sigprocmask() function examines and/or changes the  current signal
     mask  (those  signals that are blocked from delivery).  Signals are blocked
     if they are members of the current signal mask set.

     If set is not null, the action of sigprocmask()  depends  on
the value of
     the parameter how.  The signal mask is changed as a function
of the specified
 set and the current mask.  The function  is  specified
by how using
     one of the following values from <sys/signal.h>:

     SIG_BLOCK     The  new mask is the union of the current mask
and the specified
 set.

     SIG_UNBLOCK  The new mask is the intersection of the current
mask and the
                  complement of the specified set.

     SIG_SETMASK   The  current mask is replaced by the specified
set.

     If oset is not null, it is set to the previous value of  the
signal mask.
     When  set is null, the value of how is insignificant and the
mask remains
     unset providing a way to examine  the  signal  mask  without
modification.

     The  system  quietly  disallows  SIGKILL  or  SIGSTOP  to be
blocked.

RETURN VALUES    [Toc]    [Back]

     A 0 value indicated that the call succeeded.   A  -1  return
value indicates
     an  error occurred and errno is set to indicated the reason.

ERRORS    [Toc]    [Back]

     The sigprocmask() call will fail and the signal mask will be
unchanged if
     one of the following occurs:

     [EINVAL]       how has a value other than those listed here.

SEE ALSO    [Toc]    [Back]

     kill(2), sigaction(2), sigsuspend(2), sigsetops(3)

STANDARDS    [Toc]    [Back]

     The sigprocmask() function call is expected  to  conform  to
IEEE Std
     1003.1-1988 (``POSIX'').

OpenBSD      3.6                           June      4,      1993