gcc/ada/s-taenca.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA 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) 1992-2001, 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 package provides internal RTS calls implementing operations
  35 --  that apply to general entry calls, that is, calls to either
  36 --  protected or task entries.
  37
  38 --  These declarations are not part of the GNARL Interface
  39
  40 package System.Tasking.Entry_Calls is
  41
  42    procedure Wait_For_Completion (Entry_Call : Entry_Call_Link);
  43    --  This procedure suspends the calling task until the specified entry
  44    --  call has either been completed or cancelled. It performs other
  45    --  operations required of suspended tasks, such as performing
  46    --  dynamic priority changes. On exit, the call will not be queued.
  47    --  This waits for calls on task or protected entries.
  48    --  Abortion must be deferred when calling this procedure.
  49    --  Call this only when holding Self (= Entry_Call.Self) or global RTS lock.
  50
  51    procedure Wait_For_Completion_With_Timeout
  52      (Entry_Call  : Entry_Call_Link;
  53       Wakeup_Time : Duration;
  54       Mode        : Delay_Modes;
  55       Yielded     : out Boolean);
  56    --  Same as Wait_For_Completion but wait for a timeout with the value
  57    --  specified in Wakeup_Time as well.
  58    --  On return, Yielded indicates whether the wait has performed a yield.
  59    --  Check_Exception must be called after calling this procedure.
  60
  61    procedure Wait_Until_Abortable
  62      (Self_ID : Task_ID;
  63       Call    : Entry_Call_Link);
  64    --  This procedure suspends the calling task until the specified entry
  65    --  call is queued abortably or completes.
  66    --  Abortion must be deferred when calling this procedure, and the global
  67    --  RTS lock taken when Single_Lock.
  68
  69    procedure Try_To_Cancel_Entry_Call (Succeeded : out Boolean);
  70    pragma Inline (Try_To_Cancel_Entry_Call);
  71    --  Try to cancel async. entry call.
  72    --  Effect includes Abort_To_Level and Wait_For_Completion.
  73    --  Cancelled = True iff the cancelation was successful, i.e.,
  74    --  the call was not Done before this call.
  75    --  On return, the call is off-queue and the ATC level is reduced by one.
  76
  77    procedure Reset_Priority
  78      (Acceptor               : Task_ID;
  79       Acceptor_Prev_Priority : Rendezvous_Priority);
  80    pragma Inline (Reset_Priority);
  81    --  Reset the priority of a task completing an accept statement to
  82    --  the value it had before the call.
  83    --  Acceptor should always be equal to Self.
  84
  85    procedure Check_Exception
  86      (Self_ID    : Task_ID;
  87       Entry_Call : Entry_Call_Link);
  88    pragma Inline (Check_Exception);
  89    --  Raise any pending exception from the Entry_Call.
  90    --  This should be called at the end of every compiler interface procedure
  91    --  that implements an entry call.
  92    --  In principle, the caller should not be abort-deferred (unless the
  93    --  application program violates the Ada language rules by doing entry calls
  94    --  from within protected operations -- an erroneous practice apparently
  95    --  followed with success by some adventurous GNAT users).
  96    --  Absolutely, the caller should not be holding any locks, or there
  97    --  will be deadlock.
  98
  99 end System.Tasking.Entry_Calls;