pthread_sigmask(3P)					   pthread_sigmask(3P)

NAME    [Toc]    [Back]

     pthread_sigmask - examine and change blocked signals

C SYNOPSIS    [Toc]    [Back]

     #include <signal.h>

     int pthread_sigmask(int operation,	const sigset_t *set, sigset_t *old_set);

DESCRIPTION    [Toc]    [Back]

     The pthread_sigmask() function manipulates	the set	of signals which are
     blocked from delivery to the calling thread.

     A non-NULL	set specifies the set of signals to use	in modifying the
     currently active set.  The	incoming signals may be	added to, deleted from
     or	completely replace the active set, as specified	by the operation
     parameter which may have the following values:

     SIG_BLOCK	  Add specified	signals	to those in current mask.

     SIG_UNBLOCK  Remove the specified signals from the	current	mask.

     SIG_SETMASK  Replace the current mask with	set.

     If	old_set	is not NULL, the current set of	blocked	signals	(before
     modification) is returned in the space to which it	points.	 In this way,
     with a NULL set the user can determine the	current	signal mask.

     Routines described	in sigsetops() are used	to create and examine the set
     and old_set signal	masks.

     It	is not possible	to block SIGKILL or SIGSTOP.  This restriction is
     silently imposed by the system.

DIAGNOSTICS    [Toc]    [Back]

     On	success, pthread_sigmask() returns zero; otherwise, an error number is
     returned:

     [EINVAL]	    The	value specified	by operation is	not equal to one of
		    the	defined	values.

SEE ALSO    [Toc]    [Back]

     sigaction(2), sigprocmask(2), sigsetops(3), pthread_kill(3P), signal(5).

NOTES    [Toc]    [Back]

     In	IRIX, sigprocmask() it is equivalent to	pthread_sigmask().


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