2.11BSD#431 - /usr/man/cat2/sigprocmask.0

SIGPROCMASK(2)	    UNIX Programmer's Manual	   SIGPROCMASK(2)


NAME
     sigprocmask - manipulate current signal mask

SYNOPSIS
     #include <signal.h>

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

     sigset_t
     sigmask(signum)
     int signum;

DESCRIPTION
     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 sig-
     nal 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 <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 insigni-
     ficant 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
     A 0 value indicated that the call succeeded.  A -1 return
     value indicates an error occurred and errno is set to indi-
     cated the reason.


Printed 11/26/99	September 3, 1997			1


SIGPROCMASK(2)	    UNIX Programmer's Manual	   SIGPROCMASK(2)


ERRORS
     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.

     EFAULT		 set or oset contain an invalid address.

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

STANDARDS
     The sigprocmask function call is expected to conform to IEEE
     Std1003.1-1988 (``POSIX'').


Printed 11/26/99	September 3, 1997			2