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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- G N A T . T H R E A D S --
-- --
-- S p e c --
-- --
-- Copyright (C) 1998-2024, AdaCore --
-- --
-- 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 --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides facilities for creation or registration of foreign
-- threads for use as Ada tasks. In order to execute general Ada code, the
-- run-time system must know about all tasks. This package allows foreign
-- code, e.g. a C program, to create a thread that the Ada run-time knows
-- about, or to register the current thread.
-- For some implementations of GNAT Pro, the registration of foreign threads
-- is automatic. However, in such implementations, if the Ada program has no
-- tasks at all and no tasking constructs other than delay, then by default
-- the non-tasking version of the Ada run-time will be loaded. If foreign
-- threads are present, it is important to ensure that the tasking version
-- of the Ada run time is loaded. This may be achieved by adding "with
-- GNAT.Threads" to any unit in the partition.
with System;
with Ada.Task_Identification;
package GNAT.Threads is
type Void_Ptr is access all Integer;
function Create_Thread
(Code : System.Address; -- pointer
Parm : Void_Ptr; -- pointer
Size : Natural; -- int
Prio : Integer) -- int
return System.Address;
pragma Export (C, Create_Thread, "__gnat_create_thread");
-- Creates a thread with the given (Size) stack size in bytes, and
-- the given (Prio) priority. The task will execute a call to the
-- procedure whose address is given by Code. This procedure has
-- the prototype
--
-- void thread_code (void *id, void *parm);
--
-- where id is the id of the created task, and parm is the parameter
-- passed to Create_Thread. The called procedure is the body of the
-- code for the task, the task will be automatically terminated when
-- the procedure returns.
--
-- This function returns the Ada Id of the created task that can then be
-- used as a parameter to the procedures below.
--
-- C declaration:
--
-- extern void *__gnat_create_thread
-- (void (*code)(void *, void *), void *parm, int size, int prio);
function Register_Thread return System.Address;
pragma Export (C, Register_Thread, "__gnat_register_thread");
-- Create an Ada task Id for the current thread if needed.
-- If the thread could not be registered, System.Null_Address is returned.
--
-- This function returns the Ada Id of the current task that can then be
-- used as a parameter to the procedures below.
--
-- C declaration:
--
-- extern void *__gnat_register_thread ();
--
-- Here is a typical usage of the Register/Unregister_Thread procedures:
--
-- void thread_body ()
-- {
-- void *task_id = __gnat_register_thread ();
-- ... thread body ...
-- __gnat_unregister_thread ();
-- }
procedure Unregister_Thread;
pragma Export (C, Unregister_Thread, "__gnat_unregister_thread");
-- Unregister the current task from the GNAT run time and destroy the
-- memory allocated for its task id.
--
-- C declaration:
--
-- extern void __gnat_unregister_thread ();
procedure Unregister_Thread_Id (Thread : System.Address);
pragma Export (C, Unregister_Thread_Id, "__gnat_unregister_thread_id");
-- Unregister the task associated with Thread from the GNAT run time and
-- destroy the memory allocated for its task id.
-- If no task id is associated with Thread, do nothing.
--
-- C declaration:
--
-- extern void __gnat_unregister_thread_id (pthread_t *thread);
procedure Destroy_Thread (Id : System.Address);
pragma Export (C, Destroy_Thread, "__gnat_destroy_thread");
-- This procedure may be used to prematurely abort the created thread.
-- The value Id is the value that was passed to the thread code procedure
-- at activation time.
--
-- C declaration:
--
-- extern void __gnat_destroy_thread (void *id);
procedure Get_Thread (Id : System.Address; Thread : System.Address);
pragma Export (C, Get_Thread, "__gnat_get_thread");
procedure Get_Thread
(Id : Ada.Task_Identification.Task_Id; Thread : System.Address);
-- This procedure is used to retrieve the thread id of a given task.
-- The value Id is the value that was passed to the thread code procedure
-- at activation time or a Task_Id.
-- Thread is a pointer to a thread id that will be updated by this
-- procedure.
--
-- C declaration:
--
-- extern void __gnat_get_thread (void *id, pthread_t *thread);
function To_Task_Id
(Id : System.Address)
return Ada.Task_Identification.Task_Id;
-- Ada interface only.
-- Given a low level Id, as returned by Create_Thread, return a Task_Id,
-- so that operations in Ada.Task_Identification can be used.
function Make_Independent return Boolean;
-- If a procedure loads a shared library containing tasks, and that
-- procedure is considered to be a master by the compiler (because it
-- contains tasks or class-wide objects that might contain tasks),
-- then the tasks in the shared library need to call Make_Independent
-- because otherwise they will depend on the procedure that loaded the
-- shared library.
--
-- See System.Tasking.Utilities.Make_Independent in s-tasuti.ads for
-- further documentation.
end GNAT.Threads;
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