This message requests the IOProc to return an MMFORMATINFO structure containing the FOURCC of the format, the capabilities of the IOProc, and other information. This message is used to initialize MMFORMATINFO structures internally maintained by the MMIO Manager and is issued by MMIO when installing IOProcs. This message does not require that any file be opened or referenced.

ulReserved (ULONG)

Not used. No MMIOINFO block used is required for this message.

usMsg (USHORT)

Set to MMIOM_GETFORMATINFO.

lParam1 (LONG)

A pointer to an MMFORMATINFO structure. The FOURCC, media type, and related information will be written into this structure by the IOProc.

lParam2 (LONG)

This parameter is not used.

rc (ULONG)

Return codes indicating success or failure:

MMIO_SUCCESS

The specified process installed successfully.
MMIO_ERROR
The installation process failed; an error code is returned.

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