rpa::mutex_count_base Class Reference

Does the actual counting for the template class 'thread_count'. More...

#include <synchro.h>

Inheritance diagram for rpa::mutex_count_base:


Public Member Functions
	mutex_count_base ()
	~mutex_count_base ()
	The counters are checked to be sure that the mutex is properly unlocked.
void	tst_lock (void)
void	tst_unlock (void)
	The internal counter is incremented BEFORE the mutex is unlocked.
void	tst_trylock (void)
	Note that the counter is incremented AFTER the mutex is locked.
Private Member Functions
bool	dump (void) const
	Displays internal information for debugging purpose.
void	check (void) const
	Checks the mutex invariant.
Private Attributes
size_t	lockNb
	Counts the number of times 'lock()' was called.
size_t	unlockNb
	Counts the number of times 'unlock()' was called.
size_t	trylockNb
	'trylockNb' is incremented only when the 'trylock' is successful.

Detailed Description

Does the actual counting for the template class 'thread_count'.

This encapsulate a mutex in order to count the number of times it is un-/try/-locked. It also checks the consistency of these counters. The counters are changed only when the base mutex is locked. We check at runtime a very strong relation between these three counters : NbLock + NbSuccessfulTrylock = NbUnlock

Constructor & Destructor Documentation

rpa::mutex_count_base::mutex_count_base ( )

rpa::mutex_count_base::~mutex_count_base ( )

The counters are checked to be sure that the mutex is properly unlocked.

Member Function Documentation

void rpa::mutex_count_base::check ( void ) const [private]

Checks the mutex invariant.

Theoretically, we should not need any memory barrier between reads and writes to these counters, because they are properly protected by a mutex.

bool rpa::mutex_count_base::dump ( void ) const [private]

Displays internal information for debugging purpose.

This wrapper around a mutex provides a new class that still has the requested interfaces for mutexes. The three mandatory methods have all their calls counted, for statistics and for checking consistency : It computes on-the-run an invariant.

void rpa::mutex_count_base::tst_lock ( void )

Beware that the invariant of the mutex can be checked only when the mutex is locked, otherwise there may be a race condition. Also, the internal counters can be incremented only when the base mutex os locked, for the same reason.

void rpa::mutex_count_base::tst_trylock ( void )

Note that the counter is incremented AFTER the mutex is locked.

void rpa::mutex_count_base::tst_unlock ( void )

The internal counter is incremented BEFORE the mutex is unlocked.