gcc/ada/g-thread.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                         G N A T . T H R E A D S                          --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --           Copyright (C) 1998-2003 Ada Core Technologies, Inc.            --
  10 --                                                                          --
  11 -- GNAT 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 2,  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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package provides facilities for creation of foreign threads for
  35 --  use as Ada tasks. In order to execute general Ada code, the run-time
  36 --  system must know about all tasks. This package allows foreign code,
  37 --  e.g. a C program, to create a thread that the Ada run-time knows about.
  38
  39 with System;
  40 with Ada.Task_Identification;
  41
  42 package GNAT.Threads is
  43
  44    type Void_Ptr is access all Integer;
  45
  46    function Create_Thread
  47      (Code : System.Address;  -- pointer
  48       Parm : Void_Ptr;        -- pointer
  49       Size : Natural;         -- int
  50       Prio : Integer)         -- int
  51       return System.Address;
  52    pragma Export (C, Create_Thread, "__gnat_create_thread");
  53    --  Creates a thread with the given (Size) stack size in bytes, and
  54    --  the given (Prio) priority. The task will execute a call to the
  55    --  procedure whose address is given by Code. This procedure has
  56    --  the prototype
  57    --
  58    --    void thread_code (void *id, void *parm);
  59    --
  60    --  where id is the id of the created task, and parm is the parameter
  61    --  passed to Create_Thread. The called procedure is the body of the
  62    --  code for the task, the task will be automatically terminated when
  63    --  the procedure returns.
  64    --
  65    --  This function returns the Ada Id of the created task that can then be
  66    --  used as a parameter to the procedures below.
  67    --
  68    --  C declaration:
  69    --
  70    --  extern void *__gnat_create_thread
  71    --    (void (*code)(void *, void *), void *parm, int size, int prio);
  72
  73    function Register_Thread return System.Address;
  74    pragma Export (C, Register_Thread, "__gnat_register_thread");
  75    --  Create an Ada task Id for the current thread if needed.
  76    --  If the thread could not be registered, System.Null_Address is returned.
  77    --
  78    --  This function returns the Ada Id of the current task that can then be
  79    --  used as a parameter to the procedures below.
  80    --
  81    --  C declaration:
  82    --
  83    --  extern void *__gnat_register_thread ();
  84    --
  85    --  Here is a typical usage of the Register/Unregister_Thread procedures:
  86    --
  87    --  void thread_body ()
  88    --  {
  89    --    void *task_id = __gnat_register_thread ();
  90    --    ... thread body ...
  91    --    __gnat_unregister_thread ();
  92    --  }
  93
  94    procedure Unregister_Thread;
  95    pragma Export (C, Unregister_Thread, "__gnat_unregister_thread");
  96    --  Unregister the current task from the GNAT run time and destroy the
  97    --  memory allocated for its task id.
  98    --
  99    --  C declaration:
 100    --
 101    --  extern void __gnat_unregister_thread ();
 102
 103    procedure Unregister_Thread_Id (Thread : System.Address);
 104    pragma Export (C, Unregister_Thread_Id, "__gnat_unregister_thread_id");
 105    --  Unregister the task associated with Thread from the GNAT run time and
 106    --  destroy the memory allocated for its task id.
 107    --  If no task id is associated with Thread, do nothing.
 108    --
 109    --  C declaration:
 110    --
 111    --  extern void __gnat_unregister_thread_id (pthread_t *thread);
 112
 113    procedure Destroy_Thread (Id : System.Address);
 114    pragma Export (C, Destroy_Thread, "__gnat_destroy_thread");
 115    --  This procedure may be used to prematurely abort the created thread.
 116    --  The value Id is the value that was passed to the thread code procedure
 117    --  at activation time.
 118    --
 119    --  C declaration:
 120    --
 121    --  extern void __gnat_destroy_thread (void *id);
 122
 123    procedure Get_Thread (Id : System.Address; Thread : System.Address);
 124    pragma Export (C, Get_Thread, "__gnat_get_thread");
 125    --  This procedure is used to retrieve the thread id of a given task.
 126    --  The value Id is the value that was passed to the thread code procedure
 127    --  at activation time.
 128    --  Thread is a pointer to a thread id that will be updated by this
 129    --  procedure.
 130    --
 131    --  C declaration:
 132    --
 133    --  extern void __gnat_get_thread (void *id, pthread_t *thread);
 134
 135    function To_Task_Id
 136      (Id   : System.Address)
 137       return Ada.Task_Identification.Task_Id;
 138    --  Ada interface only.
 139    --  Given a low level Id, as returned by Create_Thread, return a Task_Id,
 140    --  so that operations in Ada.Task_Identification can be used.
 141
 142 end GNAT.Threads;