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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --             S Y S T E M . T A S K I N G . E N T R Y _ C A L L S          --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --         Copyright (C) 1992-2009, 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 package provides internal RTS calls implementing operations
  33 --  that apply to general entry calls, that is, calls to either
  34 --  protected or task entries.
  35
  36 --  These declarations are not part of the GNARL Interface
  37
  38 package System.Tasking.Entry_Calls is
  39
  40    procedure Wait_For_Completion (Entry_Call : Entry_Call_Link);
  41    --  This procedure suspends the calling task until the specified entry
  42    --  call has either been completed or cancelled. It performs other
  43    --  operations required of suspended tasks, such as performing
  44    --  dynamic priority changes. On exit, the call will not be queued.
  45    --  This waits for calls on task or protected entries.
  46    --  Abortion must be deferred when calling this procedure.
  47    --  Call this only when holding Self (= Entry_Call.Self) or global RTS lock.
  48
  49    procedure Wait_For_Completion_With_Timeout
  50      (Entry_Call  : Entry_Call_Link;
  51       Wakeup_Time : Duration;
  52       Mode        : Delay_Modes;
  53       Yielded     : out Boolean);
  54    --  Same as Wait_For_Completion but wait for a timeout with the value
  55    --  specified in Wakeup_Time as well.
  56    --  On return, Yielded indicates whether the wait has performed a yield.
  57    --  Check_Exception must be called after calling this procedure.
  58
  59    procedure Wait_Until_Abortable
  60      (Self_ID : Task_Id;
  61       Call    : Entry_Call_Link);
  62    --  This procedure suspends the calling task until the specified entry
  63    --  call is queued abortably or completes.
  64    --  Abortion must be deferred when calling this procedure, and the global
  65    --  RTS lock taken when Single_Lock.
  66
  67    procedure Try_To_Cancel_Entry_Call (Succeeded : out Boolean);
  68    pragma Inline (Try_To_Cancel_Entry_Call);
  69    --  Try to cancel async. entry call.
  70    --  Effect includes Abort_To_Level and Wait_For_Completion.
  71    --  Cancelled = True iff the cancellation was successful, i.e.,
  72    --  the call was not Done before this call.
  73    --  On return, the call is off-queue and the ATC level is reduced by one.
  74
  75    procedure Reset_Priority
  76      (Acceptor               : Task_Id;
  77       Acceptor_Prev_Priority : Rendezvous_Priority);
  78    pragma Inline (Reset_Priority);
  79    --  Reset the priority of a task completing an accept statement to
  80    --  the value it had before the call.
  81    --  Acceptor should always be equal to Self.
  82
  83    procedure Check_Exception
  84      (Self_ID    : Task_Id;
  85       Entry_Call : Entry_Call_Link);
  86    pragma Inline (Check_Exception);
  87    --  Raise any pending exception from the Entry_Call.
  88    --  This should be called at the end of every compiler interface procedure
  89    --  that implements an entry call.
  90    --  In principle, the caller should not be abort-deferred (unless the
  91    --  application program violates the Ada language rules by doing entry calls
  92    --  from within protected operations -- an erroneous practice apparently
  93    --  followed with success by some adventurous GNAT users).
  94    --  Absolutely, the caller should not be holding any locks, or there
  95    --  will be deadlock.
  96
  97 end System.Tasking.Entry_Calls;