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) 2015-2019, 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-- 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-- 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
32with Ada.Exceptions;
33with System.Tasking;
34with System.Task_Primitives.Operations;
35
36package 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
57end Ada.Dispatching;
58