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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- SYSTEM.TASK_PRIMITIVES.OPERATIONS.REGISTER_FOREIGN_THREAD --
-- --
-- B o d y --
-- --
-- Copyright (C) 2002-2007, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNARL; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
with System.Task_Info;
-- Use for Unspecified_Task_Info
with System.Soft_Links;
-- used to initialize TSD for a C thread, in function Self
separate (System.Task_Primitives.Operations)
function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id is
Local_ATCB : aliased Ada_Task_Control_Block (0);
Self_Id : Task_Id;
Succeeded : Boolean;
begin
-- This section is tricky. We must not call anything that might require
-- an ATCB, until the new ATCB is in place. In order to get an ATCB
-- immediately, we fake one, so that it is then possible to e.g allocate
-- memory (which might require accessing self).
-- Record this as the Task_Id for the thread
Local_ATCB.Common.LL.Thread := Thread;
Local_ATCB.Common.Current_Priority := System.Priority'First;
Specific.Set (Local_ATCB'Unchecked_Access);
-- It is now safe to use an allocator
Self_Id := new Ada_Task_Control_Block (0);
-- Finish initialization
Lock_RTS;
System.Tasking.Initialize_ATCB
(Self_Id, null, Null_Address, Null_Task,
Foreign_Task_Elaborated'Access,
System.Priority'First, Task_Info.Unspecified_Task_Info, 0, Self_Id,
Succeeded);
Unlock_RTS;
pragma Assert (Succeeded);
Self_Id.Master_of_Task := 0;
Self_Id.Master_Within := Self_Id.Master_of_Task + 1;
for L in Self_Id.Entry_Calls'Range loop
Self_Id.Entry_Calls (L).Self := Self_Id;
Self_Id.Entry_Calls (L).Level := L;
end loop;
Self_Id.Common.State := Runnable;
Self_Id.Awake_Count := 1;
Self_Id.Common.Task_Image (1 .. 14) := "foreign thread";
Self_Id.Common.Task_Image_Len := 14;
-- Since this is not an ordinary Ada task, we will start out undeferred
Self_Id.Deferral_Level := 0;
System.Soft_Links.Create_TSD (Self_Id.Common.Compiler_Data);
-- ???
-- The following call is commented out to avoid dependence on
-- the System.Tasking.Initialization package.
-- It seems that if we want Ada.Task_Attributes to work correctly
-- for C threads we will need to raise the visibility of this soft
-- link to System.Soft_Links.
-- We are putting that off until this new functionality is otherwise
-- stable.
-- System.Tasking.Initialization.Initialize_Attributes_Link.all (T);
Enter_Task (Self_Id);
return Self_Id;
end Register_Foreign_Thread;
|
