Win32 Classes

DirectShow implements several classes to handle Win32 threads, events, and critical sections. These include the following classes.

• CAMEvent
• CCritSec
• CAutoLock
• CAMThread
• CMsgThread
• CMsg

The following illustration shows these classes.

CAMEvent handles a Windows CE event as a C++ object. The methods in this class allow events to be put into the signaled state or reset to a nonsignaled state, and also allow a caller to block until an event is signaled. Events can also be cast to handles and passed to the WaitForMultipleObjects function.

CCritSec handles a Win32 critical section as a C++ object to provide intraprocess synchronization. Methods of this class allow you to create, lock, and unlock a critical section.

CAutoLock holds a critical section (a CCritSec object) for the scope of a block or function. The critical section is locked in the constructor and unlocked in the destructor.

CAMThread provides an abstract worker thread class enabling creation, synchronization, and communication with a worker thread.

CMsgThread provides support for a worker thread to which requests can be posted asynchronously instead of being sent directly. Messages, in the form of a CMsg object, can be posted to a CMsgThread object.

CMsg creates an object containing a message to be passed to a CMsgThread object.

Last updated on Wednesday, April 13, 2005

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