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/*
* Copyright (C) 2010-2014 Paul Davis <paul@linuxaudiosystems.com>
* Copyright (C) 2015-2017 Robin Gareus <robin@gareus.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "pbd/semutils.h"
#include "pbd/failed_constructor.h"
using namespace PBD;
Semaphore::Semaphore (const char* name, int val)
{
#ifdef WINDOWS_SEMAPHORE
if ((_sem = CreateSemaphore(NULL, val, 32767, name)) == NULL) {
throw failed_constructor ();
}
#elif __APPLE__
if ((_sem = sem_open (name, O_CREAT, 0600, val)) == (sem_t*) SEM_FAILED) {
throw failed_constructor ();
}
/* this semaphore does not exist for IPC */
if (sem_unlink (name)) {
throw failed_constructor ();
}
#else
(void) name; /* stop gcc warning on !Apple systems */
if (sem_init (&_sem, 0, val)) {
throw failed_constructor ();
}
#endif
}
Semaphore::~Semaphore ()
{
#ifdef WINDOWS_SEMAPHORE
CloseHandle(_sem);
#elif __APPLE__
sem_close (ptr_to_sem());
#endif
}
#ifdef WINDOWS_SEMAPHORE
int
Semaphore::signal ()
{
// non-zero on success, opposite to posix
return !ReleaseSemaphore(_sem, 1, NULL);
}
int
Semaphore::wait ()
{
DWORD result = 0;
result = WaitForSingleObject(_sem, INFINITE);
return (result == WAIT_OBJECT_0);
}
int
Semaphore::reset ()
{
int rv = -1;
DWORD result;
do {
++rv;
result = WaitForSingleObject(_sem, 0);
} while (result == WAIT_OBJECT_0);
return rv;
}
#endif
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