gcc/ada/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 -- 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
  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;