sigset(3C)																sigset(3C)

NAME

       sigset(), sighold(), sigrelse(), sigignore() - signal management

SYNOPSIS

DESCRIPTION

       The system defines a set of signals that can be delivered to a process.	The set of signals is defined in signal(5), along with the meaning
       and side effects of each signal.  An alternate mechanism for handling these signals is defined here.  The facilities described here  should
       not be used in conjunction with the other facilities described under signal(2) and sigspace(2).

       allows the calling process to choose one of four ways to handle the receipt of a specific signal.  sig specifies the signal and func speci-
       fies the action handler.

       sig can be any one of the signals described under signal(5) except or

       func is assigned one of four values: or a function address.  The actions prescribed by and are described under signal(5).  The action  pre-
       scribed by and function address are described below:

       Hold signal.

			 The  signal sig is held upon receipt.	Any pending signal of this signal type remains held.  Only one signal of each type
			 is held.

			 Note: the signals and cannot be held.

       function address  Catch signal.

			 func must be a pointer to a function, the signal-catching handler, that is called when signal sig occurs.  specifies that
			 the  process  calls this function upon receipt of signal sig.	Any pending signal of this type is released.  This handler
			 address is retained across calls to the other signal management functions listed here.  Upon receipt of signal  sig,  the
			 receiving  process executes the signal-catching function pointed to by func as described under signal(5) with the follow-
			 ing differences:

			 Before calling the signal-catching handler, the defined action of sig is set to During a normal return from  the  signal-
			 catching  handler,  the  defined action is restored to func and any held signal of this type is released.  If a non-local
			 goto (longjmp(3C)) is taken, must be called to restore the defined action to func and release any  held  signal  of  this
			 type.

       holds  the  signal  sig.   restores the defined action of sig to that specified previously by and are used to establish critical regions of
       code.  is analogous to raising the priority level and deferring or holding a signal until the priority is lowered by

       sets the action for signal sig to (see signal(5)).

RETURN VALUE

       Upon successful completion, returns the previous value of the defined action for the specified  signal  sig.   Otherwise,  a  value  of	is
       returned and is set to indicate the error.  is defined in

       For the other functions, a 0 value indicates that the call succeeded.  A -1 return value indicates an error occurred and is set to indicate
       the reason.

ERRORS

       fails and the defined action for sig is not changed if any of the following occur:

	      The	     func argument points to memory that is not a valid part of the process address space.   Reliable  detection  of  this
			     error is implementation dependent.

       and and fail and the defined action for sig is not changed if any of the following occur:

	      sig	     is not a valid signal number.

	      An attempt is made to ignore, hold, or supply a handler
			     for a signal that cannot be ignored, held, or caught; see signal(5).

WARNINGS

       These signal facilities should not be used in conjunction with signal(2) and sigspace(2).

SEE ALSO

       kill(1), kill(2), pause(2), signal(2), sigspace(2), wait(2), abort(3C), setjmp(3C), sigpause(3C), signal(5).

STANDARDS CONFORMANCE

																	sigset(3C)