CMultiLock Class

Artigo
04/28/2015

Represents the access-control mechanism used in controlling access to resources in a multithreaded program.

class CMultiLock

Members

Public Constructors

Name	Description
CMultiLock::CMultiLock	Constructs a CMultiLock object.

Public Methods

Name	Description
CMultiLock::IsLocked	Determines if a specific synchronization object in the array is locked.
CMultiLock::Lock	Waits on the array of synchronization objects.
CMultiLock::Unlock	Releases any owned synchronization objects.

Remarks

CMultiLock does not have a base class.

To use the synchronization classes CSemaphore, CMutex, and CEvent, you can create either a CMultiLock or CSingleLock object to wait on and release the synchronization object. Use CMultiLock when there are multiple objects that you could use at a particular time. Use CSingleLock when you only need to wait on one object at a time.

To use a CMultiLock object, first create an array of the synchronization objects that you wish to wait on. Next, call the CMultiLock object's constructor inside a member function in the controlled resource's class. Then call the Lock member function to determine if a resource is available (signaled). If one is, continue with the remainder of the member function. If no resource is available, either wait for a specified amount of time for a resource to be released, or return failure. After use of a resource is complete, either call the Unlock function if the CMultiLock object is to be used again, or allow the CMultiLock object to be destroyed.

CMultiLock objects are most useful when a thread has a large number of CEvent objects it can respond to. Create an array containing all the CEvent pointers, and call Lock. This will cause the thread to wait until one of the events is signaled.

For more information on how to use CMultiLock objects, see the article Multithreading: How to Use the Synchronization Classes.

Inheritance Hierarchy

CMultiLock

Requirements

Header: afxmt.h

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