


      SSIGNAL(3C)                 (UNIX 5.0)                SSIGNAL(3C)



      NAME
           ssignal, gsignal - software signals

      SYNTAX
           #include <signal.h>

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

           int gsignal (sig)
           int sig;

      DESCRIPTION
           Ssignal and gsignal implement a software facility similar to
           signal(2).  This facility is used by the Standard C Library
           to enable users to indicate the disposition 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 15. 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
           established 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
           constants SIG_DFL (default) or SIG_IGN (ignore).  Ssignal
           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.

           Gsignal 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.




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      SSIGNAL(3C)                 (UNIX 5.0)                SSIGNAL(3C)



      NOTES
           There are some additional signals with numbers outside the
           range 1 through 15 which are used by the Standard C Library
           to indicate error conditions.  Thus, some signal numbers
           outside the range 1 through 15 are legal, although their use
           may interfere with the operation of the Standard C Library.

















































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