------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- SYSTEM.TASK_PRIMITIVES.OPERATIONS.SPECIFIC -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2019, 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 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 POSIX version of this package where foreign threads are -- recognized. separate (System.Task_Primitives.Operations) package body Specific is ATCB_Key : aliased pthread_key_t; -- Key used to find the Ada Task_Id associated with a thread ---------------- -- Initialize -- ---------------- procedure Initialize (Environment_Task : Task_Id) is pragma Warnings (Off, Environment_Task); Result : Interfaces.C.int; begin Result := pthread_key_create (ATCB_Key'Access, null); pragma Assert (Result = 0); end Initialize; ------------------- -- Is_Valid_Task -- ------------------- function Is_Valid_Task return Boolean is begin return pthread_getspecific (ATCB_Key) /= System.Null_Address; end Is_Valid_Task; --------- -- Set -- --------- procedure Set (Self_Id : Task_Id) is Result : Interfaces.C.int; begin Result := pthread_setspecific (ATCB_Key, To_Address (Self_Id)); pragma Assert (Result = 0); 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 : System.Address; begin Result := pthread_getspecific (ATCB_Key); -- If the key value is Null then it is a non-Ada task if Result /= System.Null_Address then return To_Task_Id (Result); else return Register_Foreign_Thread; end if; end Self; end Specific;