File : a-dispat.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- A D A . D I S P A T C H I N G --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 2015, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT 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 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 with Ada.Exceptions;
33 with System.Tasking;
34 with System.Task_Primitives.Operations;
35
36 package body Ada.Dispatching is
37
38 procedure Yield is
39 Self_Id : constant System.Tasking.Task_Id :=
40 System.Task_Primitives.Operations.Self;
41
42 begin
43 -- If pragma Detect_Blocking is active, Program_Error must be
44 -- raised if this potentially blocking operation is called from a
45 -- protected action.
46
47 if System.Tasking.Detect_Blocking
48 and then Self_Id.Common.Protected_Action_Nesting > 0
49 then
50 Ada.Exceptions.Raise_Exception
51 (Program_Error'Identity, "potentially blocking operation");
52 else
53 System.Task_Primitives.Operations.Yield;
54 end if;
55 end Yield;
56
57 end Ada.Dispatching;