gcc/ada/s-tpopsp-lynxos.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --    S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S .   --
   6 --                              S P E C I F I C                             --
   7 --                                                                          --
   8 --                                 B o d y                                  --
   9 --                                                                          --
  10 --         Copyright (C) 1992-2005, Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  21 -- Boston, MA 02110-1301, USA.                                              --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University.       --
  31 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This is a LynxOS version of this package.
  36
  37 separate (System.Task_Primitives.Operations)
  38 package body Specific is
  39
  40    ----------------
  41    -- Initialize --
  42    ----------------
  43
  44    procedure Initialize (Environment_Task : Task_Id) is
  45       pragma Warnings (Off, Environment_Task);
  46       Result : Interfaces.C.int;
  47
  48    begin
  49       Result := st_keycreate (null, ATCB_Key'Access);
  50       pragma Assert (Result = 0);
  51    end Initialize;
  52
  53    -------------------
  54    -- Is_Valid_Task --
  55    -------------------
  56
  57    function Is_Valid_Task return Boolean is
  58       Result : Interfaces.C.int;
  59       Value : aliased System.Address;
  60    begin
  61       Result := st_getspecific (ATCB_Key, Value'Address);
  62       pragma Assert (Result = 0);
  63       return (Value /= System.Null_Address);
  64    end Is_Valid_Task;
  65
  66    ---------
  67    -- Set --
  68    ---------
  69
  70    procedure Set (Self_Id : Task_Id) is
  71       Result : Interfaces.C.int;
  72
  73    begin
  74       Result := st_setspecific (ATCB_Key, To_Address (Self_Id));
  75       pragma Assert (Result = 0);
  76    end Set;
  77
  78    ----------
  79    -- Self --
  80    ----------
  81
  82    --  To make Ada tasks and C threads interoperate better, we have added some
  83    --  functionality to Self. Suppose a C main program (with threads) calls an
  84    --  Ada procedure and the Ada procedure calls the tasking runtime system.
  85    --  Eventually, a call will be made to self. Since the call is not coming
  86    --  from an Ada task, there will be no corresponding ATCB.
  87
  88    --  What we do in Self is to catch references that do not come from
  89    --  recognized Ada tasks, and create an ATCB for the calling thread.
  90
  91    --  The new ATCB will be "detached" from the normal Ada task master
  92    --  hierarchy, much like the existing implicitly created signal-server
  93    --  tasks.
  94
  95    function Self return Task_Id is
  96       Value : aliased System.Address;
  97
  98       Result : Interfaces.C.int;
  99       pragma Unreferenced (Result);
 100
 101    begin
 102       Result := st_getspecific (ATCB_Key, Value'Address);
 103       --  Is it OK not to check this result???
 104
 105       --  If the key value is Null, then it is a non-Ada task.
 106
 107       if Value /= System.Null_Address then
 108          return To_Task_Id (Value);
 109       else
 110          return Register_Foreign_Thread;
 111       end if;
 112    end Self;
 113
 114 end Specific;