SAMPLE: How to Use Multimedia Timer Services on Windows 95 |
Q153400
The information in this article applies to:
- Microsoft Win32 Software Development Kit (SDK), version 4.0
SUMMARY
MTHUNK32 contains a sample application that demonstrates the implementation of thunking code necessary for 32-bit applications running on Windows 95 to obtain reliable performance when using high-resolution multimedia timer services.
MORE INFORMATION
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32-bit multimedia timer callbacks on Windows 95 are subject to noticeable performance problems due to the demands of preemptive multitasking and limitations in the Windows 95 system architecture. Running a 32-bit application at high priority does not solve this problem, but thunking to a 16-bit DLL does the job. MTHUNK32 demonstrates how a 32-bit application running on Windows 95 can utilize flat thunks via a 32-bit thunking DLL to call a 16-bit DLL that invokes a multimedia timer and services the timer callbacks.
MTHUNK32 also implements a shared memory technique using the 16-bit and 32-bit DLLs, and a user interface for manipulating parameters in shared memory. This design allows the user to interact through the 32-bit application's GUI to modify data while it is being played back with the 16-bit multimedia services. This sort of design is needed by MIDI sequencer applications which allow a user to modify MIDI data for entire tracks or channels during playback by manipulating graphical controls or manually entering new parameters. To implement this technique on Windows 95, the 32-bit application and 16-bit DLL must share one or more blocks of fixed memory that are allocated by the 16-bit DLL. The DLL passes a pointer to the memory block through the thunking layer back to the application which then can reference the memory.
Additional query words: timeSetEvent TimerProc kbfile MTHUNK32.EXE
Keywords : kbmm kbSDKWin32 kbOSWin95
Issue type :
Technology : kbWin32SDKSearch kbAudDeveloper kbSDKSearch kbWin32sSearch kbWin32SDK400
Last Reviewed: November 26, 1999 |
