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MFLockPlatform function

Blocks the MFShutdown function.


HRESULT MFLockPlatform(void);


This function has no parameters.

Return value

The function returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Return codeDescription

The function succeeded.



This function prevents work queue threads from being shut down when MFShutdown is called. Use this function to ensure that asynchronous operations complete gracefully before the platform shuts down.

This function holds a lock on the Media Foundation platform. To unlock the platform, call MFUnlockPlatform. The application must call MFUnlockPlatform once for every call to MFLockPlatform.

The MFShutdown function blocks until the platform is unlocked, or until a fixed wait period has elapsed. (The wait period is a few seconds.) To avoid memory leaks, the application should unlock the platform before the wait period ends. For example, cancel any asynchronous operations that are waiting to complete and are holding a lock on the platform.

The default implementation of the IMFAsyncResult interface automatically locks the Media Foundation platform when the result object is created. Releasing the interface unlocks the platform. Therefore, in most cases your application does not need to lock the platform directly. For more information, see Work Queues.

This function is available on the following platforms if the Windows Media Format 11 SDK redistributable components are installed:

  • Windows XP with Service Pack 2 (SP2) and later.
  • Windows XP Media Center Edition 2005 with KB900325 (Windows XP Media Center Edition 2005) and KB925766 (October 2006 Update Rollup for Windows XP Media Center Edition) installed.


Minimum supported client

Windows Vista [desktop apps | UWP apps]

Minimum supported server

Windows Server 2008 [desktop apps | UWP apps]

Minimum supported phone

Windows Phone 8







See also

Media Foundation Functions
Media Foundation Platform APIs
Work Queues



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