gcc/ada/4hexcpol.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
   4 --                                                                          --
   5 --                   A D A . E X C E P T I O N S . P O L L                  --
   6 --       (version supporting asynchronous abort test and time slicing)      --
   7 --                                                                          --
   8 --                                  B o d y                                 --
   9 --                                                                          --
  10 --                                                                          --
  11 --          Copyright (C) 1992-2000, Free Software Foundation, Inc.         --
  12 --                                                                          --
  13 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
  31 -- GNARL was developed by the GNARL team at Florida State University.       --
  32 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This version is for targets that do not support per-thread asynchronous
  37 --  signals or that do not handle async timers properly. On such targets, we
  38 --  require compilation with the -gnatP switch that activates periodic polling.
  39 --  Then in the body of the polling routine we test for asynchronous abort and
  40 --  yield periodically.
  41
  42 --  HP-UX and SCO currently use this file
  43
  44 with System.Soft_Links;
  45 --  used for Check_Abort_Status
  46
  47 separate (Ada.Exceptions)
  48
  49 ----------
  50 -- Poll --
  51 ----------
  52
  53 procedure Poll is
  54 begin
  55    if Counter = 10000 then
  56       Counter := 0;
  57       delay 0.0;
  58    else
  59       Counter := Counter + 1;
  60    end if;
  61
  62    --  Test for asynchronous abort on each poll
  63
  64    if System.Soft_Links.Check_Abort_Status.all /= 0 then
  65       raise Standard'Abort_Signal;
  66    end if;
  67 end Poll;