SSIGNAL(3C-SVR3)    RISC/os Reference Manual     SSIGNAL(3C-SVR3)



NAME
     ssignal, gsignal - software signals

SYNOPSIS
     #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 condi-
     tions, 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 SIGDFL (default) or SIGIGN (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 SIGDFL.

     Gsignal raises the signal identified by its argument, sig:

          If an action function has been established for sig,
          then that action is reset to SIGDFL 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 SIGIGN, gsignal returns the
          value 1 and takes no other action.

          If the action for sig is SIGDFL, 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.




                        Printed 11/19/92                   Page 1

SSIGNAL(3C-SVR3)    RISC/os Reference Manual     SSIGNAL(3C-SVR3)



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.














































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