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
38package 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
97end System.Tasking.Entry_Calls;
98