A wrapper class for a Posix condition variable. More...

#include <ThreadSupport.h>

Public Member Functions
	Cond () throw ()
	Construct a POSIX condition variable, with default attributes. More...

	Cond (const Cond &x) throw ()
	Copy constructor. More...

	~Cond ()
	Destruct a Cond. More...

void	lock () throw (Exception)
	Lock the mutex associated with the condition variable. More...

void	unlock () throw (Exception)
	Unlock the mutex associated with the condition variable. More...

void	signal () throw (Exception)
	Unblock at least one thread waiting on the condition variable. More...

void	broadcast ()
	Restart all threads waiting on the condition variable. More...

void	wait () throw (Exception)
	Wait on the condition variable. More...

Private Member Functions
Cond &	operator= (const Cond &)
	No assignment allowed. More...

Private Attributes
pthread_cond_t	_p_cond

Mutex	_mutex

Detailed Description

A wrapper class for a Posix condition variable.

Constructor & Destructor Documentation

Cond::Cond	(	)
throw	(
	)

Construct a POSIX condition variable, with default attributes.

See man page for pthread_cond_init.

Cond::Cond	(	const Cond &	x	)
throw	(
	)

Copy constructor.

Creates new unlocked condition variable and mutex.

Cond::~Cond ( )

Destruct a Cond.

See man page for pthread_cond_destroy. Cond must not be waited on by any thread, otherwise std::terminate() is called.

References _p_cond, CLOG, and nidas::util::Exception::what().

Member Function Documentation

void nidas::util::Cond::broadcast ( )

inline

Restart all threads waiting on the condition variable.

See Also: lock().

References _p_cond.

Referenced by PacketReader::loop(), nidas::core::SampleBuffer::run(), nidas::core::SampleSorter::run(), and nidas::util::Multisync::sync().

void nidas::util::Cond::lock	(		)
throw	(	Exception
	)

inline

Lock the mutex associated with the condition variable.

Here is an example (lifted from the pthread_cond_init man page): of two threads sharing variables x and y. One thread waits for a signal that x is greater than y:

int x,y;
Cond xyCond;
...
xyCond.lock();
while (x <= y) xyCond.wait();
// operate on x and y
xyCond.unlock();

Another thread manipulates x and y and signals when x > y:

xyCond.lock();
// modify x and y
if (x > y) xyCond.signal();
xyCond.unlock();

References _mutex, and nidas::util::Mutex::lock().

Cond& nidas::util::Cond::operator= ( const Cond & )

private

No assignment allowed.

void nidas::util::Cond::signal	(		)
throw	(	Exception
	)

inline

Unblock at least one thread waiting on the condition variable.

See Also: lock() for an example. According to the man page, it is not safe to call Cond::signal() from an asynchronous signal handler.

References _p_cond.

Referenced by nidas::core::SampleOutputRequestThread::addConnectRequest(), nidas::core::SampleOutputRequestThread::addDeleteRequest(), nidas::dynld::raf::SyncRecordReader::endOfStream(), nidas::core::SampleSorter::flush(), nidas::core::SampleBuffer::heapDecrement(), nidas::core::SampleSorter::heapDecrement(), nidas::core::SampleOutputRequestThread::interrupt(), nidas::core::SensorOpener::interrupt(), nidas::core::SampleBuffer::interrupt(), nidas::core::SampleSorter::interrupt(), nidas::dynld::raf::SyncRecordReader::nextSample(), nidas::util::McSocket< SocketT >::offer(), nidas::core::SensorOpener::openSensor(), nidas::core::SensorOpener::reopenSensor(), and nidas::core::SampleSorter::run().

void nidas::util::Cond::unlock	(		)
throw	(	Exception
	)

inline

Unlock the mutex associated with the condition variable.

See Also: lock() for an example.

References _mutex, and nidas::util::Mutex::unlock().

void Cond::wait	(		)
throw	(	Exception
	)

Wait on the condition variable.

See Also

lock() for an example. wait() does several things:

It immediately unlocks the mutex
It blocks until the condition variable is signalled
It locks the mutex again wait() is a cancellation point, which sets up the appropriate cancellation cleanup handlers so that the mutex is unlocked if the thread is cancelled.

References _mutex, _p_cond, and nidas::util::Mutex::ptr().

Referenced by nidas::util::McSocket< SocketT >::accept(), nidas::util::McSocket< SocketT >::connect(), nidas::core::SampleSorter::flush(), nidas::dynld::raf::SyncRecordReader::nextSample(), nidas::core::SampleOutputRequestThread::run(), nidas::core::SensorOpener::run(), nidas::core::SampleBuffer::run(), nidas::core::SampleSorter::run(), WriterThread::run(), and nidas::util::Multisync::sync().

Member Data Documentation

Mutex nidas::util::Cond::_mutex

private

Referenced by lock(), unlock(), and wait().

pthread_cond_t nidas::util::Cond::_p_cond

private

Referenced by broadcast(), signal(), wait(), and ~Cond().

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

nidas/util/ThreadSupport.h
nidas/util/ThreadSupport.cc

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation