lunchbox::Lock Class Reference

A lock (mutex) primitive. More...

#include <lock.h>

Inheritance diagram for lunchbox::Lock:

Collaboration diagram for lunchbox::Lock:

Public Member Functions
	Lock ()
	Construct a new lock. More...
	~Lock ()
	Destruct the lock. More...
void	set ()
	Acquire the lock. More...
void	unset ()
	Release the lock. More...
void	setRead ()
	Acquire the lock shared with other readers. More...
void	unsetRead ()
	Release a shared read lock. More...
bool	trySet ()
	Attempt to acquire the lock. More...
bool	isSet ()
	Test if the lock is set. More...

Detailed Description

A lock (mutex) primitive.

See also

ScopedMutex

Deprecated:

Use boost::mutex

Example:

/* Copyright (c) 2006-2016, Stefan Eilemann <eile@equalizergraphics.com>
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License version 2.1 as published
 * by the Free Software Foundation.
 *
 * This library 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 Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define TEST_RUNTIME 600 // seconds, needed for NighlyMemoryCheck
#include <lunchbox/test.h>

#include <lunchbox/clock.h>
#include <lunchbox/debug.h>
#include <lunchbox/init.h>
#include <lunchbox/lock.h>
#include <lunchbox/spinLock.h>
#include <lunchbox/timedLock.h>

#include <iostream>

#define MAXTHREADS 256
#define TIME       500  // ms

lunchbox::Clock _clock;
bool _running = false;

template< class T > class Thread : public lunchbox::Thread
{
public:
    Thread() : lock( 0 ), ops( 0 ) {}

    T* lock;
    size_t ops;

    virtual void run()
    {
        ops = 0;
        while( LB_LIKELY( _running ))
        {
            lock->set();
            lock->unset();
            ++ops;
        }
    }
};

template< class T > void _test()
{
    const size_t nThreads = 16;

    T lock;
    lock.set();

    Thread< T > threads[MAXTHREADS];
    for( size_t i = 1; i <= nThreads; i = i << 1 )
    {
        _running = true;
        for( size_t j = 0; j < i; ++j )
        {
            threads[j].lock = &lock;
            TEST( threads[j].start( ));
        }
        lunchbox::sleep( 10 ); // let threads initialize

        _clock.reset();
        lock.unset();
        lunchbox::sleep( TIME ); // let threads run
        _running = false;

        for( size_t j = 0; j < i; ++j )
            TEST( threads[j].join( ));
        const float time = _clock.getTimef();

#ifndef NDEBUG
        TEST( !lock.isSet( ));
#endif
        lock.set();

        size_t ops = 0;
        for( size_t j = 0; j < nThreads; ++j )
            ops += threads[j].ops;

        std::cout << std::setw(20) << lunchbox::className( lock ) << ", "
                  << std::setw(12) << /*set, test, unset*/ 3 * ops / time
                  << ", " << std::setw(3) << i << std::endl;
    }
}

int main( int argc, char **argv )
{
    TEST( lunchbox::init( argc, argv ));

    std::cout << "               Class,       ops/ms, threads" << std::endl;
    _test< lunchbox::SpinLock >();
    std::cout << std::endl;

    _test< lunchbox::Lock >();
    std::cout << std::endl;

    _test< lunchbox::TimedLock >();
    TEST( lunchbox::exit( ));

    return EXIT_SUCCESS;
}

Definition at line 36 of file lock.h.

Constructor & Destructor Documentation

lunchbox::Lock::Lock

(

)

Construct a new lock.

Version

1.0

lunchbox::Lock::~Lock

(

)

Destruct the lock.

Version

1.0

Member Function Documentation

bool lunchbox::Lock::isSet

(

)

Test if the lock is set.

Returns

true if the lock is set, false if it is not set.

Version

1.0

void lunchbox::Lock::set

(

)

Acquire the lock.

Version

1.0

void lunchbox::Lock::setRead ( )

inline

Acquire the lock shared with other readers.

Version

1.3.2

Definition at line 52 of file lock.h.

bool lunchbox::Lock::trySet

(

)

Attempt to acquire the lock.

This method implements an atomic test-and-set operation.

Returns

true if the lock was set, false if it was not set.

Version

1.0

void lunchbox::Lock::unset

(

)

Release the lock.

Version

1.0

void lunchbox::Lock::unsetRead ( )

inline

Release a shared read lock.

Version

1.3.2

Definition at line 55 of file lock.h.

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The documentation for this class was generated from the following file:

• lock.h