gcc/ada/7staspri.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 --                                                                          --
  10 --            Copyright (C) 1991-2000, Florida State University             --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University. It is --
  31 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  32 -- State University (http://www.gnat.com).                                  --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This is a POSIX-like version of this package.
  37 --  Note: this file can only be used for POSIX compliant systems.
  38
  39 pragma Polling (Off);
  40 --  Turn off polling, we do not want ATC polling to take place during
  41 --  tasking operations. It causes infinite loops and other problems.
  42
  43 with System.OS_Interface;
  44 --  used for pthread_mutex_t
  45 --           pthread_cond_t
  46 --           pthread_t
  47
  48 package System.Task_Primitives is
  49
  50    type Lock is limited private;
  51    --  Should be used for implementation of protected objects.
  52
  53    type RTS_Lock is limited private;
  54    --  Should be used inside the runtime system.
  55    --  The difference between Lock and the RTS_Lock is that the later
  56    --  one serves only as a semaphore so that do not check for
  57    --  ceiling violations.
  58
  59    type Task_Body_Access is access procedure;
  60    --  Pointer to the task body's entry point (or possibly a wrapper
  61    --  declared local to the GNARL).
  62
  63    type Private_Data is limited private;
  64    --  Any information that the GNULLI needs maintained on a per-task
  65    --  basis.  A component of this type is guaranteed to be included
  66    --  in the Ada_Task_Control_Block.
  67
  68 private
  69
  70    type Lock is new System.OS_Interface.pthread_mutex_t;
  71    type RTS_Lock is new System.OS_Interface.pthread_mutex_t;
  72
  73    type Private_Data is record
  74       Thread : aliased System.OS_Interface.pthread_t;
  75       pragma Atomic (Thread);
  76       --  Thread field may be updated by two different threads of control.
  77       --  (See, Enter_Task and Create_Task in s-taprop.adb).
  78       --  They put the same value (thr_self value). We do not want to
  79       --  use lock on those operations and the only thing we have to
  80       --  make sure is that they are updated in atomic fashion.
  81
  82       LWP : aliased System.Address;
  83       --  The purpose of this field is to provide a better tasking support on
  84       --  gdb. The order of the two first fields (Thread and LWP) is important.
  85       --  On targets where lwp is not relevant, this is equivalent to Thread.
  86
  87       CV : aliased System.OS_Interface.pthread_cond_t;
  88
  89       L  : aliased RTS_Lock;
  90       --  Protection for all components is lock L
  91    end record;
  92
  93 end System.Task_Primitives;