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MMIOM_READ message

  • Article

The MMIOM_READ message is sent to an I/O procedure by the mmioRead function to request that a specified number of bytes be read from an open file.

MMIOM_READ 
lParam1 = (LPARAM) lBuffer 
lParam2 = (LPARAM) cbRead

Parameters

lBuffer

Pointer to the buffer to be filled with data read from the file.

cbRead

Number of bytes to read from file.

Return Value

Returns the number of bytes actually read from the file. If no more bytes can be read, the return value is 0. If there is an error, the return value is 1.

Remarks

The I/O procedure is responsible for updating the lDiskOffset member of the MMIOINFO structure to reflect the new file position after the read operation.

Requirements

Requirement Value
Minimum supported client
 Windows 2000 Professional [desktop apps only]
Minimum supported server
 Windows 2000 Server [desktop apps only]
Header
Mmsystem.h (include Windows.h)