2 Copyright (C) 2010 Paul Davis
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 #include "pbd/semutils.h"
20 #include "pbd/failed_constructor.h"
24 Semaphore::Semaphore (const char* name, int val)
26 #ifdef WINDOWS_SEMAPHORE
27 if ((_sem = CreateSemaphore(NULL, val, 32767, name)) == NULL) {
28 throw failed_constructor ();
32 if ((_sem = sem_open (name, O_CREAT, 0600, val)) == (sem_t*) SEM_FAILED) {
33 throw failed_constructor ();
36 /* this semaphore does not exist for IPC */
38 if (sem_unlink (name)) {
39 throw failed_constructor ();
43 (void) name; /* stop gcc warning on !Apple systems */
45 if (sem_init (&_sem, 0, val)) {
46 throw failed_constructor ();
51 Semaphore::~Semaphore ()
53 #ifdef WINDOWS_SEMAPHORE
56 sem_close (ptr_to_sem());
60 #ifdef WINDOWS_SEMAPHORE
65 // non-zero on success, opposite to posix
66 return !ReleaseSemaphore(_sem, 1, NULL);
73 result = WaitForSingleObject(_sem, INFINITE);
74 return (result == WAIT_OBJECT_0);