| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- A D A . S Y N C H R O N O U S _ B A R R I E R S -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2011, Free Software Foundation, Inc. -- |
| -- -- |
| -- This specification is derived from the Ada Reference Manual for use with -- |
| -- GNAT. The copyright notice above, and the license provisions that follow -- |
| -- apply solely to the contents of the part following the private keyword. -- |
| -- -- |
| -- GNAT 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 3, or (at your option) any later ver- -- |
| -- sion. GNAT 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. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| package body Ada.Synchronous_Barriers is |
| |
| protected body Synchronous_Barrier is |
| |
| -- The condition "Wait'Count = Release_Threshold" opens the barrier when |
| -- the required number of tasks is reached. The condition "Keep_Open" |
| -- leaves the barrier open while there are queued tasks. While there are |
| -- tasks in the queue no new task will be queued (no new protected |
| -- action can be started on a protected object while another protected |
| -- action on the same protected object is underway, RM 9.5.1 (4)), |
| -- guaranteeing that the barrier will remain open only for those tasks |
| -- already inside the queue when the barrier was open. |
| |
| entry Wait (Notified : out Boolean) |
| when Keep_Open or else Wait'Count = Release_Threshold |
| is |
| begin |
| -- If we are executing the entry it means that the required number of |
| -- tasks have been queued in the entry. Keep_Open barrier will remain |
| -- true until all queued tasks are out. |
| |
| Keep_Open := Wait'Count > 0; |
| |
| -- The last released task will close the barrier and get the Notified |
| -- token. |
| |
| Notified := Wait'Count = 0; |
| end Wait; |
| end Synchronous_Barrier; |
| |
| ---------------------- |
| -- Wait_For_Release -- |
| ---------------------- |
| |
| procedure Wait_For_Release |
| (The_Barrier : in out Synchronous_Barrier; |
| Notified : out Boolean) |
| is |
| begin |
| The_Barrier.Wait (Notified); |
| end Wait_For_Release; |
| |
| end Ada.Synchronous_Barriers; |
