CppCommon::ConditionVariable Class Reference

Condition variable synchronization primitive. More...

#include <condition_variable.h>

Public Member Functions
	ConditionVariable ()
	ConditionVariable (const ConditionVariable &)=delete
	ConditionVariable (ConditionVariable &&cv)=delete
	~ConditionVariable ()
ConditionVariable &	operator= (const ConditionVariable &)=delete
ConditionVariable &	operator= (ConditionVariable &&cv)=delete
void	NotifyOne ()
	Notify one of waiting thread about event occurred. More...
void	NotifyAll ()
	Notify all waiting threads about event occurred. More...
void	Wait (CriticalSection &cs)
	Wait until condition variable is notified. More...
template<typename TPredicate >
void	Wait (CriticalSection &cs, TPredicate predicate)
	Wait until condition variable is notified using the given predicate. More...
bool	TryWaitFor (CriticalSection &cs, const Timespan &timespan)
	Try to wait for the given timespan until condition variable is notified. More...
template<typename TPredicate >
bool	TryWaitFor (CriticalSection &cs, const Timespan &timespan, TPredicate predicate)
	Try to wait for the given timespan until condition variable is notified using the given predicate. More...
bool	TryWaitUntil (CriticalSection &cs, const UtcTimestamp &timestamp)
	Try to wait until the given timestamp until condition variable is notified. More...
template<typename TPredicate >
bool	TryWaitUntil (CriticalSection &cs, const UtcTimestamp &timestamp, TPredicate predicate)
	Try to wait until the given timestamp until condition variable is notified using the given predicate. More...

Detailed Description

Condition variable synchronization primitive.

Condition variable is a synchronization primitive that enable threads to wait until a particular condition occurs. Condition variables are user-mode objects that cannot be shared across processes.

Condition variables enable threads to atomically release a lock and enter the sleeping state. They can be used with critical sections. Condition variables support operations that "notify one" or "notify all" waiting threads. After a thread is woken, it re-acquires the lock it released when the thread entered the sleeping state.

Thread-safe.

https://en.wikipedia.org/wiki/Monitor_(synchronization)

Examples

threads_condition_variable.cpp.

Definition at line 32 of file condition_variable.h.

Constructor & Destructor Documentation

ConditionVariable() [1/3]

CppCommon::ConditionVariable::ConditionVariable

(

)

Definition at line 120 of file condition_variable.cpp.

ConditionVariable() [2/3]

CppCommon::ConditionVariable::ConditionVariable ( const ConditionVariable &  )

delete

ConditionVariable() [3/3]

CppCommon::ConditionVariable::ConditionVariable ( ConditionVariable &&  cv )

delete

~ConditionVariable()

CppCommon::ConditionVariable::~ConditionVariable

(

)

Definition at line 131 of file condition_variable.cpp.

Member Function Documentation

NotifyAll()

void CppCommon::ConditionVariable::NotifyAll

(

)

Notify all waiting threads about event occurred.

Unblocks all threads currently waiting for this condition. If no threads are waiting, the function does nothing.

Will not block.

Examples

threads_condition_variable.cpp.

Definition at line 138 of file condition_variable.cpp.

NotifyOne()

void CppCommon::ConditionVariable::NotifyOne

(

)

Notify one of waiting thread about event occurred.

Unblocks one of the threads currently waiting for this condition. If no threads are waiting, the function does nothing. If more than one, it is unspecified which of the threads is selected.

Will not block.

Examples

threads_condition_variable.cpp.

Definition at line 137 of file condition_variable.cpp.

operator=() [1/2]

ConditionVariable& CppCommon::ConditionVariable::operator= ( ConditionVariable &&  cv )

delete

operator=() [2/2]

ConditionVariable& CppCommon::ConditionVariable::operator= ( const ConditionVariable &  )

delete

TryWaitFor() [1/2]

bool CppCommon::ConditionVariable::TryWaitFor	(	CriticalSection &	cs,
		const Timespan &	timespan
	)

Try to wait for the given timespan until condition variable is notified.

The execution of the current thread (which shall have locked critical section) is blocked during timespan, or until notified (if the latter happens first).

Will block for the given timespan in the worst case.

Parameters

cs	- Critical section (must be locked)
timespan	- Timespan to wait for the condition variable notification

Returns

'true' if the condition variable was successfully notified, 'false' if the timeout was occurred

Definition at line 142 of file condition_variable.cpp.

TryWaitFor() [2/2]

template<typename TPredicate >

bool CppCommon::ConditionVariable::TryWaitFor	(	CriticalSection &	cs,
		const Timespan &	timespan,
		TPredicate	predicate
	)

Try to wait for the given timespan until condition variable is notified using the given predicate.

This method is equivalent to:

Timestamp timeout = UtcTimestamp() + timespan;
while (!predicate())
    if (!TryWaitFor(cs, timeout - UtcTimestamp()))
        return predicate();
return true;

Will block for the given timespan in the worst case.

Parameters

cs	- Critical section (must be locked)
timespan	- Timespan to wait for the condition variable notification
predicate	- Predicate to check

Returns

'true' if the condition variable was successfully notified, 'false' if the timeout was occurred

Definition at line 19 of file condition_variable.inl.

TryWaitUntil() [1/2]

bool CppCommon::ConditionVariable::TryWaitUntil ( CriticalSection &  cs, const UtcTimestamp &  timestamp  )

inline

Try to wait until the given timestamp until condition variable is notified.

The execution of the current thread (which shall have locked critical section) is blocked either until notified or until timestamp, whichever happens first.

Will block until the given timestamp in the worst case.

Parameters

cs	- Critical section (must be locked)
timestamp	- Timestamp to stop wait for the condition variable notification

Returns

'true' if the condition variable was successfully notified, 'false' if the timeout was occurred

Definition at line 131 of file condition_variable.h.

TryWaitUntil() [2/2]

template<typename TPredicate >

bool CppCommon::ConditionVariable::TryWaitUntil ( CriticalSection &  cs, const UtcTimestamp &  timestamp, TPredicate  predicate  )

inline

Try to wait until the given timestamp until condition variable is notified using the given predicate.

This method is equivalent to:

return TryWaitFor(cs, timestamp - UtcTimestamp(), predicate);

Will block until the given timestamp in the worst case.

Parameters

cs	- Critical section (must be locked)
timestamp	- Timestamp to stop wait for the condition variable notification
predicate	- Predicate to check

Returns

'true' if the condition variable was successfully notified, 'false' if the timeout was occurred

Definition at line 148 of file condition_variable.h.

Wait() [1/2]

void CppCommon::ConditionVariable::Wait

(

CriticalSection &

cs

)

Wait until condition variable is notified.

The execution of the current thread (which shall have locked critical section) is blocked until notified.

Will block.

Parameters

cs	- Critical section (must be locked)

Examples

threads_condition_variable.cpp.

Definition at line 140 of file condition_variable.cpp.

Wait() [2/2]

template<typename TPredicate >

void CppCommon::ConditionVariable::Wait	(	CriticalSection &	cs,
		TPredicate	predicate
	)

Wait until condition variable is notified using the given predicate.

This method is equivalent to:

while (!predicate()) Wait(cs);

Will block.

Parameters

cs	- Critical section (must be locked)
predicate	- Predicate to check

Definition at line 12 of file condition_variable.inl.

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

• include/threads/condition_variable.h
• include/threads/condition_variable.inl
• source/threads/condition_variable.cpp