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Q77697: PRB: sndPlaySound with SND_MEMORY and SND_ASYNC Flags Hangs

Article: Q77697
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.0,3.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 05-NOV-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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SYMPTOMS
========

When an application uses the sndPlaySound() API to play a wave file with both
the SND_ASYNC and SND_MEMORY flags set, Windows hangs.

CAUSE
=====

The memory used to store the wave becomes invalid before the wave file is
finished playing.

RESOLUTION
==========

Ensure that the memory used to store the wave remains valid until the wave is
complete.

MORE INFORMATION
================

As it plays the sound, Windows must be able to access the memory used to store
the wave file. If this memory is deleted during playback, Windows will hang
because the memory is no longer valid. The memory can be deleted if an
application starts to play a sound and exits. All memory allocated by an
application is freed upon exit.

To terminate the playback of a asynchronous wave initiated by sndPlaySound(),
call sndPlaySound() with the lpszSoundName parameter set to NULL. This should be
done only when an application is playing an asynchronous sound from memory and
it is necessary to stop playing the sound. For example, this should be done if
the application is playing a sound from memory and the user closes the
application.

Note: The memory allocated for the wave file must be shared. All shared memory
allocated in a DLL (dynamic-link library) is owned by the DLL. Other memory
allocated in a DLL is owned by the application that calls the DLL. When the DLL
is freed, all shared memory allocated by the DLL is freed. Therefore, if the DLL
that allocates the memory to hold the wave is freed before sndPlaySound is
complete, Windows will hang.

Additional query words: no32bit 3.00 3.10

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

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