------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- SYSTEM.TASK_PRIMITIVES.OPERATIONS.SPECIFIC -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2018, Free Software Foundation, Inc. -- -- -- -- GNAT 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 3, or (at your option) any later ver- -- -- sion. GNAT 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. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is a VxWorks version of this package using Thread_Local_Storage -- support (VxWorks 6.6 and higher). The implementation is based on __threads -- support. separate (System.Task_Primitives.Operations) package body Specific is ATCB : aliased Task_Id := null; -- Ada Task_Id associated with a thread pragma Thread_Local_Storage (ATCB); ---------------- -- Initialize -- ---------------- procedure Initialize is begin null; end Initialize; ------------------- -- Is_Valid_Task -- ------------------- function Is_Valid_Task return Boolean is begin return ATCB /= Null_Task; end Is_Valid_Task; --------- -- Set -- --------- procedure Set (Self_Id : Task_Id) is begin ATCB := Self_Id; end Set; ---------- -- Self -- ---------- -- To make Ada tasks and C threads interoperate better, we have added some -- functionality to Self. Suppose a C main program (with threads) calls an -- Ada procedure and the Ada procedure calls the tasking runtime system. -- Eventually, a call will be made to self. Since the call is not coming -- from an Ada task, there will be no corresponding ATCB. -- What we do in Self is to catch references that do not come from -- recognized Ada tasks, and create an ATCB for the calling thread. -- The new ATCB will be "detached" from the normal Ada task master -- hierarchy, much like the existing implicitly created signal-server -- tasks. function Self return Task_Id is Result : constant Task_Id := ATCB; begin if Result /= null then return Result; else -- If the value is Null then it is a non-Ada task return Register_Foreign_Thread; end if; end Self; end Specific;