critical_section.h File Reference

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Classes
struct	critical_section< Lock >
struct	critical_section< Lock *& >
	Helper class for CRITICAL_SECTION idiom (macro). More...

Macros
#define	CRITICAL_SECTION(name, lock)   critical_section<__typeof__(lock)&> name(lock)
#define	SPECIALIZE_CS(Lock, Extra, ExtraInit, Acquire, Release)
	Macro that enables use of CRITICAL_SECTION(name,lock) More...

Functions
	SPECIALIZE_CS (pthread_mutex_t, int _dummy,(_dummy=0), pthread_mutex_lock(_mutex), pthread_mutex_unlock(_mutex))

Macro Definition Documentation

CRITICAL_SECTION

#define CRITICAL_SECTION	(		name,
			lock
	)		critical_section<__typeof__(lock)&> name(lock)

This macro starts a critical section protected by the given lock (2nd argument). The critical_section structure it creates is named by the 1st argument. The rest of the scope (in which this macro is used) becomes the scope of the critical section, since it is the destruction of this critical_section structure that releases the lock.

The programmer can release the lock early by calling <name>.pause() or <name>.exit(). The programmer can reacquire the lock by calling <name>.resume() if <name>.pause() was called, but not after <name>.exit().

See also

critical_section

SPECIALIZE_CS

#define SPECIALIZE_CS	(		Lock,
			Extra,
			ExtraInit,
			Acquire,
			Release
	)

Value:

template<>  struct critical_section<Lock&> { \
critical_section(Lock &mutex) \
    : _mutex(&mutex)          \
    {   ExtraInit; Acquire; } \
    ~critical_section() {     \
        if(_mutex)            \
            Release;          \
            _mutex = nullptr;    \
        }                     \
    void pause() { Release; } \
    void resume() { Acquire; }\
    void exit() { Release; _mutex = nullptr; } \
    Lock &hand_off() {        \
        Lock* rval = _mutex;  \
        _mutex = nullptr;        \
        return *rval;         \
    }                         \
private:                      \
    Lock* _mutex;             \
    Extra;                    \
    void operator=(critical_section const &);   \
    critical_section(critical_section const &); \
}

Macro that enables use of CRITICAL_SECTION(name,lock)

Create a templated class that holds

• a reference to the given lock and
• the Extra (2nd macro argument)

and it

• applies the ExtraInit and Acquire commands upon construction,
• applies the Release command upon destruction.

Function Documentation

SPECIALIZE_CS()

SPECIALIZE_CS	(	pthread_mutex_t	,
		int	_dummy,
		(_dummy=0)	,
		pthread_mutex_lock(_mutex)	,
		pthread_mutex_unlock(_mutex)
	)