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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 -- --
19 -- --
20 -- --
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;