gcc/ada/g-ctrl_c.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                          G N A T . C T R L _ C                           --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --               Copyright (C) 2002 Ada Core Technologies, Inc.             --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package may be used to intercept the interruption of a running
  35 --  program by the operator typing Control-C, without having to use an Ada
  36 --  interrupt handler protected object.
  37 --
  38 --  This package is currently implemented under Windows and Unix platforms.
  39 --
  40 --  Note concerning Unix systems:
  41
  42 --  The behavior of this package when using tasking depends on the interaction
  43 --  between sigaction() and the thread library.
  44
  45 --  On most implementations, the interaction will be no different whether
  46 --  tasking is involved or not. An exception is GNU/Linux systems where
  47 --  each task/thread is considered as a separate process by the kernel,
  48 --  meaning in particular that a Ctrl-C from the keyboard will be sent to
  49 --  all tasks instead of only one, resulting in multiple calls to the handler.
  50
  51 package GNAT.Ctrl_C is
  52
  53    type Handler_Type is access procedure;
  54    --  Any parameterless library level procedure can be used as a handler.
  55    --  Handler_Type should not propagate exceptions.
  56
  57    procedure Install_Handler (Handler : Handler_Type);
  58    --  Set up Handler to be called if the operator hits Ctrl-C.
  59
  60    procedure Uninstall_Handler;
  61    --  Reinstall the standard Control-C handler.
  62    --  If Install_Handler has never been called, this procedure has no effect.
  63
  64 private
  65    pragma Import (C, Install_Handler, "__gnat_install_int_handler");
  66    pragma Import (C, Uninstall_Handler, "__gnat_uninstall_int_handler");
  67 end GNAT.Ctrl_C;