gcc/ada/s-taspri-hpux-dce.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                  GNAT 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) 1991-2011, 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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is a HP-UX version of this package
  33
  34 --  This package provides low-level support for most tasking features
  35
  36 pragma Polling (Off);
  37 --  Turn off polling, we do not want ATC polling to take place during tasking
  38 --  operations. It causes infinite loops and other problems.
  39
  40 with System.OS_Interface;
  41
  42 package System.Task_Primitives is
  43    pragma Preelaborate;
  44
  45    type Lock is limited private;
  46    --  Should be used for implementation of protected objects
  47
  48    type RTS_Lock is limited private;
  49    --  Should be used inside the runtime system. The difference between Lock
  50    --  and the RTS_Lock is that the later one serves only as a semaphore so
  51    --  that do not check for ceiling violations.
  52
  53    type Suspension_Object is limited private;
  54    --  Should be used for the implementation of Ada.Synchronous_Task_Control
  55
  56    type Task_Body_Access is access procedure;
  57    --  Pointer to the task body's entry point (or possibly a wrapper
  58    --  declared local to the GNARL).
  59
  60    type Private_Data is limited private;
  61    --  Any information that the GNULLI needs maintained on a per-task basis.
  62    --  A component of this type is guaranteed to be included in the
  63    --  Ada_Task_Control_Block.
  64
  65    subtype Task_Address is System.Address;
  66    --  In some versions of Task_Primitives, notably for VMS, Task_Address is
  67    --  the short version of address defined in System.Aux_DEC. To avoid
  68    --  dragging Aux_DEC into tasking packages a tasking specific subtype is
  69    --  defined here.
  70
  71    Task_Address_Size : constant := Standard'Address_Size;
  72    --  The size of Task_Address
  73
  74    Alternate_Stack_Size : constant := 0;
  75    --  No alternate signal stack is used on this platform
  76
  77 private
  78    type Lock is record
  79       L              : aliased System.OS_Interface.pthread_mutex_t;
  80       Priority       : Integer;
  81       Owner_Priority : Integer;
  82    end record;
  83
  84    type RTS_Lock is new System.OS_Interface.pthread_mutex_t;
  85
  86    type Suspension_Object is record
  87       State   : Boolean;
  88       pragma Atomic (State);
  89       --  Boolean that indicates whether the object is open. This field is
  90       --  marked Atomic to ensure that we can read its value without locking
  91       --  the access to the Suspension_Object.
  92
  93       Waiting : Boolean;
  94       --  Flag showing if there is a task already suspended on this object
  95
  96       L : aliased System.OS_Interface.pthread_mutex_t;
  97       --  Protection for ensuring mutual exclusion on the Suspension_Object
  98
  99       CV : aliased System.OS_Interface.pthread_cond_t;
 100       --  Condition variable used to queue threads until condition is signaled
 101    end record;
 102
 103    type Private_Data is record
 104       Thread : aliased System.OS_Interface.pthread_t;
 105       pragma Atomic (Thread);
 106       --  Thread field may be updated by two different threads of control.
 107       --  (See, Enter_Task and Create_Task in s-taprop.adb). They put the
 108       --  same value (thr_self value). We do not want to use lock on those
 109       --  operations and the only thing we have to make sure is that they
 110       --  are updated in atomic fashion.
 111
 112       CV : aliased System.OS_Interface.pthread_cond_t;
 113
 114       L : aliased RTS_Lock;
 115       --  Protection for all components is lock L
 116    end record;
 117
 118 end System.Task_Primitives;