1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K I N G . E N T R Y _ C A L L S --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2005, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNARL; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides internal RTS calls implementing operations
-- that apply to general entry calls, that is, calls to either
-- protected or task entries.
-- These declarations are not part of the GNARL Interface
package System.Tasking.Entry_Calls is
procedure Wait_For_Completion (Entry_Call : Entry_Call_Link);
-- This procedure suspends the calling task until the specified entry
-- call has either been completed or cancelled. It performs other
-- operations required of suspended tasks, such as performing
-- dynamic priority changes. On exit, the call will not be queued.
-- This waits for calls on task or protected entries.
-- Abortion must be deferred when calling this procedure.
-- Call this only when holding Self (= Entry_Call.Self) or global RTS lock.
procedure Wait_For_Completion_With_Timeout
(Entry_Call : Entry_Call_Link;
Wakeup_Time : Duration;
Mode : Delay_Modes;
Yielded : out Boolean);
-- Same as Wait_For_Completion but wait for a timeout with the value
-- specified in Wakeup_Time as well.
-- On return, Yielded indicates whether the wait has performed a yield.
-- Check_Exception must be called after calling this procedure.
procedure Wait_Until_Abortable
(Self_ID : Task_Id;
Call : Entry_Call_Link);
-- This procedure suspends the calling task until the specified entry
-- call is queued abortably or completes.
-- Abortion must be deferred when calling this procedure, and the global
-- RTS lock taken when Single_Lock.
procedure Try_To_Cancel_Entry_Call (Succeeded : out Boolean);
pragma Inline (Try_To_Cancel_Entry_Call);
-- Try to cancel async. entry call.
-- Effect includes Abort_To_Level and Wait_For_Completion.
-- Cancelled = True iff the cancelation was successful, i.e.,
-- the call was not Done before this call.
-- On return, the call is off-queue and the ATC level is reduced by one.
procedure Reset_Priority
(Acceptor : Task_Id;
Acceptor_Prev_Priority : Rendezvous_Priority);
pragma Inline (Reset_Priority);
-- Reset the priority of a task completing an accept statement to
-- the value it had before the call.
-- Acceptor should always be equal to Self.
procedure Check_Exception
(Self_ID : Task_Id;
Entry_Call : Entry_Call_Link);
pragma Inline (Check_Exception);
-- Raise any pending exception from the Entry_Call.
-- This should be called at the end of every compiler interface procedure
-- that implements an entry call.
-- In principle, the caller should not be abort-deferred (unless the
-- application program violates the Ada language rules by doing entry calls
-- from within protected operations -- an erroneous practice apparently
-- followed with success by some adventurous GNAT users).
-- Absolutely, the caller should not be holding any locks, or there
-- will be deadlock.
end System.Tasking.Entry_Calls;
|
