SSIGNAL(3C)          INTERACTIVE UNIX System          SSIGNAL(3C)



          NAME
               ssignal, gsignal - software signals

          SYNOPSIS
               #include <signal.h>

               int (*ssignal (sig, action))( )
               int sig, (*action)( );

               int gsignal (sig)
               int sig;

          DESCRIPTION
               The ssignal and gsignal functions implement a software
               facility similar to signal(2).  This facility is used by the
               Standard C Library to enable users to indicate the disposi-
               tion of error conditions, and is also made available to
               users for their own purposes.

               Software signals made available to users are associated with
               integers in the inclusive range 1 through 16. A call to
               ssignal associates a procedure, action, with the software
               signal sig; the software signal, sig, is raised by a call to
               gsignal.  Raising a software signal causes the action esta-
               blished for that signal to be taken.

               The first argument to ssignal is a number identifying the
               type of signal for which an action is to be established. The
               second argument defines the action; it is either the name of
               a (user-defined) action function or one of the manifest con-
               stants SIG_DFL (default) or SIG_IGN (ignore).  The ssignal
               function returns the action previously established for that
               signal type; if no action has been established or the signal
               number is illegal, ssignal returns SIG_DFL.

               The gsignal function raises the signal identified by its
               argument, sig:

                    If an action function has been established for sig,
                    then that action is reset to SIG_DFL and the action
                    function is entered with argument sig.  Gsignal returns
                    the value returned to it by the action function.

                    If the action for sig is SIG_IGN, gsignal returns the
                    value 1 and takes no other action.

                    If the action for sig is SIG_DFL, gsignal returns the
                    value 0 and takes no other action.

                    If sig has an illegal value or no action was ever
                    specified for sig, gsignal returns the value 0 and
                    takes no other action.



          Rev. C Software Development Set                            Page 1

          SSIGNAL(3C)          INTERACTIVE UNIX System          SSIGNAL(3C)



          SEE ALSO
               signal(2), sigset(2).

          NOTES
               There are some additional signals with numbers outside the
               range 1 through 16 which are used by the Standard C Library
               to indicate error conditions.  Thus, some signal numbers
               outside the range 1 through 16 are legal, although their use
               may interfere with the operation of the Standard C Library.














































          Rev. C Software Development Set                            Page 2