juce::GenericScopedTryLock< LockType > Class Template Reference

Automatically locks and unlocks a mutex object. More...

#include <juce_ScopedLock.h>

Collaboration diagram for juce::GenericScopedTryLock< LockType >:

Public Member Functions
	GenericScopedTryLock (const LockType &lock, bool acquireLockOnInitialisation=true) noexcept
	Creates a GenericScopedTryLock. More...
	~GenericScopedTryLock () noexcept
	Destructor. More...
bool	isLocked () const noexcept
	Returns true if the mutex was successfully locked. More...
bool	retryLock () const noexcept
	Retry gaining the lock by calling tryEnter on the underlying lock. More...

Private Attributes
const LockType &	lock_
bool	lockWasSuccessful

Detailed Description

template<class LockType>
class juce::GenericScopedTryLock< LockType >

Automatically locks and unlocks a mutex object.

Use one of these as a local variable to provide RAII-based locking of a mutex.

The templated class could be a CriticalSection, SpinLock, or anything else that provides enter() and exit() methods.

e.g.

CriticalSection myCriticalSection;
 
for (;;)
{
    const GenericScopedTryLock<CriticalSection> myScopedTryLock (myCriticalSection);
 
    // Unlike using a ScopedLock, this may fail to actually get the lock, so you
    // should test this with the isLocked() method before doing your thread-unsafe
    // action..
    if (myScopedTryLock.isLocked())
    {
       ...do some stuff...
    }
    else
    {
        ..our attempt at locking failed because another thread had already locked it..
    }
 
    // myCriticalSection gets unlocked here (if it was locked)
}

See also

CriticalSection::tryEnter, GenericScopedLock, GenericScopedUnlock

@tags{Core}

Constructor & Destructor Documentation

GenericScopedTryLock()

template<class LockType >

juce::GenericScopedTryLock< LockType >::GenericScopedTryLock ( const LockType &  lock, bool  acquireLockOnInitialisation = true  )

inlineexplicitnoexcept

Creates a GenericScopedTryLock.

If acquireLockOnInitialisation is true then as soon as this ScopedTryLock is created, it will attempt to acquire the lock with tryEnter.

You can retry acquiring the lock by calling retryLock.

When GenericScopedTryLock is deleted, the lock will be released (if the lock was successfully acquired).

Make sure this object is created and deleted by the same thread, otherwise there are no guarantees what will happen! Best just to use it as a local stack object, rather than creating one with the new() operator.

See also

retryLock, isLocked

~GenericScopedTryLock()

template<class LockType >

juce::GenericScopedTryLock< LockType >::~GenericScopedTryLock ( )

inlinenoexcept

Destructor.

The mutex will be unlocked (if it had been successfully locked) when the destructor is called.

Make sure this object is created and deleted by the same thread, otherwise there are no guarantees what will happen!

References juce::GenericScopedTryLock< LockType >::lock_, and juce::GenericScopedTryLock< LockType >::lockWasSuccessful.

Member Function Documentation

isLocked()

template<class LockType >

bool juce::GenericScopedTryLock< LockType >::isLocked ( ) const

inlinenoexcept

Returns true if the mutex was successfully locked.

References juce::GenericScopedTryLock< LockType >::lockWasSuccessful.

retryLock()

template<class LockType >

bool juce::GenericScopedTryLock< LockType >::retryLock ( ) const

inlinenoexcept

Retry gaining the lock by calling tryEnter on the underlying lock.

References juce::GenericScopedTryLock< LockType >::lock_, and juce::GenericScopedTryLock< LockType >::lockWasSuccessful.

Member Data Documentation

lock_

template<class LockType >

const LockType& juce::GenericScopedTryLock< LockType >::lock_

private

Referenced by juce::GenericScopedTryLock< LockType >::retryLock(), and juce::GenericScopedTryLock< LockType >::~GenericScopedTryLock().

lockWasSuccessful

template<class LockType >

bool juce::GenericScopedTryLock< LockType >::lockWasSuccessful

mutableprivate

Referenced by juce::GenericScopedTryLock< LockType >::isLocked(), juce::GenericScopedTryLock< LockType >::retryLock(), and juce::GenericScopedTryLock< LockType >::~GenericScopedTryLock().

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

• juce_ScopedLock.h