sigblock(3UCB)					     SunOS/BSD Compatibility Library Functions					    sigblock(3UCB)

NAME

       sigblock, sigmask, sigpause, sigsetmask - block signals

SYNOPSIS

       /usr/ucb/cc [ flag ... ] file ...
       #include <signal.h>

       int sigblock(mask);
       intmask;

       int sigmask( signum);
       int signum;

       int sigpause(int mask);
       int mask;

       int sigsetmask( mask);
       int mask;

DESCRIPTION

       sigblock, sigmask, sigpause, sigsetmask - block signals

       sigblock()  adds  the  signals  specified  in mask to the set of signals currently being blocked from delivery.	Signals are blocked if the
       appropriate bit in mask is a 1; the macro sigmask is provided to construct the mask for a given signum.	sigblock()  returns  the  previous
       mask. The previous mask may be restored using sigsetmask().

       sigpause()  assigns  mask  to  the  set	of  masked  signals  and then waits for a signal to arrive; on return the set of masked signals is
       restored. mask is usually 0 to indicate that no signals are now to be blocked. sigpause() always terminates by being interrupted, returning
       -1 and setting errno to EINTR.

       sigsetmask()  sets the current signal mask (those signals that are blocked from delivery).  Signals are blocked if the corresponding bit in
       mask is a 1; the macro sigmask is provided to construct the mask for a given signum.

       In normal usage, a signal is blocked using sigblock(). To begin a critical section, variables modified on the occurrence of the signal  are
       examined  to determine that there is no work to be done, and the process pauses awaiting work by using sigpause() with the mask returned by
       sigblock().

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

RETURN VALUES

       sigblock() and sigsetmask() return the previous set of masked signals. sigpause() returns -1 and sets errno to EINTR.

SEE ALSO

       kill(2), sigaction(2), signal(3UCB), sigvec(3UCB)

NOTES

       Use of these interfaces should be restricted to only applications written on BSD platforms.  Use of these interfaces with any of the system
       libraries or in multi-thread applications is unsupported.

SunOS 5.10							    19 Feb 1993 						    sigblock(3UCB)