A condition variable enables threads to atomically block and test the condition under the protection of a mutual exclu- sion lock (mutex) until the condition is satisfied. That is, the mutex must have been held by the thread before calling wait or signal on the condition. If the condition is false, a thread blocks on a condition variable and atomically releases the mutex that is waiting for the condition to change. If another thread changes the condition, it may wake up waiting threads by signaling the associated condition variable. The waiting threads, upon awakening, reacquire the mutex and re-evaluate the condition.
#include <ace/Synch_T.h>
template<class MUTEX> class ACE_Condition {
public:
ACE_Condition ( MUTEX &m, int type = USYNC_THREAD, LPCTSTR name = 0, void *arg = 0 );
~ACE_Condition (void);
int wait (const ACE_Time_Value *abstime);
int wait (void);
int wait (MUTEX &mutex, const ACE_Time_Value *abstime = 0);
int signal (void);
int broadcast (void);
int remove (void);
MUTEX &mutex (void);
void dump (void) const;
protected:
ACE_cond_t cond_;
MUTEX &mutex_;
private:
inline ACE_UNIMPLEMENTED_FUNC ( void operator= (const ACE_Condition<MUTEX> &) );
};
ACE_Condition (
MUTEX &m,
int type = USYNC_THREAD,
LPCTSTR name = 0,
void *arg = 0
);
~ACE_Condition (void);
int wait (const ACE_Time_Value *abstime);
wait
semantics. Else, if abstime
!= 0 and the call times out before the condition is signaled
wait
returns -1 and sets errno to ETIME.
int wait (void);
int wait (MUTEX &mutex, const ACE_Time_Value *abstime = 0);
mutex
passed as a parameter (this is useful if you need to store the
Condition
in shared memory). Else, if abstime
!= 0 and the
call times out before the condition is signaled wait
returns -1
and sets errno to ETIME.
int signal (void);
int broadcast (void);
int remove (void);
MUTEX &mutex (void);
void dump (void) const;
ACE_ALLOC_HOOK_DECLARE; Declare the dynamic allocation hooks.
inline ACE_UNIMPLEMENTED_FUNC (
void operator= (const ACE_Condition<MUTEX> &)
);