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/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtCore/qatomic.h>
#include <limits.h>
#include <sched.h>
extern "C" {
int q_atomic_trylock_int(volatile int *addr);
int q_atomic_trylock_ptr(volatile void *addr);
Q_CORE_EXPORT int q_atomic_lock_int(volatile int *addr)
{
int returnValue = q_atomic_trylock_int(addr);
if (returnValue == INT_MIN) {
do {
// spin until we think we can succeed
do {
sched_yield();
returnValue = *addr;
} while (returnValue == INT_MIN);
// try again
returnValue = q_atomic_trylock_int(addr);
} while (returnValue == INT_MIN);
}
return returnValue;
}
Q_CORE_EXPORT int q_atomic_lock_ptr(volatile void *addr)
{
int returnValue = q_atomic_trylock_ptr(addr);
if (returnValue == -1) {
do {
// spin until we think we can succeed
do {
sched_yield();
returnValue = *reinterpret_cast<volatile int *>(addr);
} while (returnValue == -1);
// try again
returnValue = q_atomic_trylock_ptr(addr);
} while (returnValue == -1);
}
return returnValue;
}
} // extern "C"
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