gcc/ada/s-tpopsp-lynxos.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --                SYSTEM.TASK_PRIMITIVES.OPERATIONS.SPECIFIC                --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --         Copyright (C) 1992-2009, Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- GNARL 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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is a LynxOS version of this package.
  33
  34 separate (System.Task_Primitives.Operations)
  35 package body Specific is
  36
  37    ----------------
  38    -- Initialize --
  39    ----------------
  40
  41    procedure Initialize (Environment_Task : Task_Id) is
  42       pragma Warnings (Off, Environment_Task);
  43       Result : Interfaces.C.int;
  44
  45    begin
  46       Result := st_keycreate (null, ATCB_Key'Access);
  47       pragma Assert (Result = 0);
  48    end Initialize;
  49
  50    -------------------
  51    -- Is_Valid_Task --
  52    -------------------
  53
  54    function Is_Valid_Task return Boolean is
  55       Result : Interfaces.C.int;
  56       Value : aliased System.Address;
  57    begin
  58       Result := st_getspecific (ATCB_Key, Value'Address);
  59       pragma Assert (Result = 0);
  60       return (Value /= System.Null_Address);
  61    end Is_Valid_Task;
  62
  63    ---------
  64    -- Set --
  65    ---------
  66
  67    procedure Set (Self_Id : Task_Id) is
  68       Result : Interfaces.C.int;
  69
  70    begin
  71       Result := st_setspecific (ATCB_Key, To_Address (Self_Id));
  72       pragma Assert (Result = 0);
  73    end Set;
  74
  75    ----------
  76    -- Self --
  77    ----------
  78
  79    --  To make Ada tasks and C threads interoperate better, we have added some
  80    --  functionality to Self. Suppose a C main program (with threads) calls an
  81    --  Ada procedure and the Ada procedure calls the tasking runtime system.
  82    --  Eventually, a call will be made to self. Since the call is not coming
  83    --  from an Ada task, there will be no corresponding ATCB.
  84
  85    --  What we do in Self is to catch references that do not come from
  86    --  recognized Ada tasks, and create an ATCB for the calling thread.
  87
  88    --  The new ATCB will be "detached" from the normal Ada task master
  89    --  hierarchy, much like the existing implicitly created signal-server
  90    --  tasks.
  91
  92    function Self return Task_Id is
  93       Value : aliased System.Address;
  94
  95       Result : Interfaces.C.int;
  96       pragma Unreferenced (Result);
  97
  98    begin
  99       Result := st_getspecific (ATCB_Key, Value'Address);
 100       --  Is it OK not to check this result???
 101
 102       --  If the key value is Null, then it is a non-Ada task.
 103
 104       if Value /= System.Null_Address then
 105          return To_Task_Id (Value);
 106       else
 107          return Register_Foreign_Thread;
 108       end if;
 109    end Self;
 110
 111 end Specific;