g-ctrl_c.ads   [plain text]


------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
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--                          G N A T . C T R L _ C                           --
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--               Copyright (C) 2002 Ada Core Technologies, Inc.             --
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------------------------------------------------------------------------------

--  This package may be used to intercept the interruption of a running
--  program by the operator typing Control-C, without having to use an Ada
--  interrupt handler protected object.
--
--  This package is currently implemented under Windows and Unix platforms.
--
--  Note concerning Unix systems:

--  The behavior of this package when using tasking depends on the interaction
--  between sigaction() and the thread library.

--  On most implementations, the interaction will be no different whether
--  tasking is involved or not. An exception is GNU/Linux systems where
--  each task/thread is considered as a separate process by the kernel,
--  meaning in particular that a Ctrl-C from the keyboard will be sent to
--  all tasks instead of only one, resulting in multiple calls to the handler.

package GNAT.Ctrl_C is

   type Handler_Type is access procedure;
   --  Any parameterless library level procedure can be used as a handler.
   --  Handler_Type should not propagate exceptions.

   procedure Install_Handler (Handler : Handler_Type);
   --  Set up Handler to be called if the operator hits Ctrl-C.

   procedure Uninstall_Handler;
   --  Reinstall the standard Control-C handler.
   --  If Install_Handler has never been called, this procedure has no effect.

private
   pragma Import (C, Install_Handler, "__gnat_install_int_handler");
   pragma Import (C, Uninstall_Handler, "__gnat_uninstall_int_handler");
end GNAT.Ctrl_C;