gcc/ada/5ztaspri.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS              --
   4 --                                                                          --
   5 --                 S Y S T E M . T A S K _ P R I M I T I V E S              --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 2001-2002 Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- GNARL 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. GNARL 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 GNARL; 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 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This is a VxWorks version of this package.
  35
  36 pragma Polling (Off);
  37 --  Turn off polling, we do not want ATC polling to take place during
  38 --  tasking operations. It causes infinite loops and other problems.
  39
  40 with System.OS_Interface;
  41
  42 package System.Task_Primitives is
  43
  44    type Lock is limited private;
  45    --  Should be used for implementation of protected objects.
  46
  47    type RTS_Lock is limited private;
  48    --  Should be used inside the runtime system.
  49    --  The difference between Lock and the RTS_Lock is that the later
  50    --  one serves only as a semaphore so that do not check for
  51    --  ceiling violations.
  52
  53    type Task_Body_Access is access procedure;
  54    --  Pointer to the task body's entry point (or possibly a wrapper
  55    --  declared local to the GNARL).
  56
  57    type Private_Data is limited private;
  58    --  Any information that the GNULLI needs maintained on a per-task
  59    --  basis.  A component of this type is guaranteed to be included
  60    --  in the Ada_Task_Control_Block.
  61
  62 private
  63
  64    type Priority_Type is (Prio_None, Prio_Protect, Prio_Inherit);
  65
  66    type Lock is record
  67       Mutex        : System.OS_Interface.SEM_ID;
  68       Protocol     : Priority_Type;
  69       Prio_Ceiling : System.OS_Interface.int;
  70       --  priority ceiling of lock
  71    end record;
  72
  73    type RTS_Lock is new Lock;
  74
  75    type Private_Data is record
  76       Thread : aliased System.OS_Interface.t_id := 0;
  77       pragma Atomic (Thread);
  78       --  Thread field may be updated by two different threads of control.
  79       --  (See, Enter_Task and Create_Task in s-taprop.adb).
  80       --  They put the same value (thr_self value). We do not want to
  81       --  use lock on those operations and the only thing we have to
  82       --  make sure is that they are updated in atomic fashion.
  83
  84       LWP : aliased System.Address;
  85       --  The purpose of this field is to provide a better tasking support on
  86       --  gdb. The order of the two first fields (Thread and LWP) is important.
  87       --  On targets where lwp is not relevant, this is equivalent to Thread.
  88
  89       CV : aliased System.OS_Interface.SEM_ID;
  90
  91       L  : aliased RTS_Lock;
  92       --  Protection for all components is lock L
  93    end record;
  94
  95 end System.Task_Primitives;