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
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.
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.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in mmsystem.h.
Multimedia File I/O Overview, Multimedia File I/O Messages, mmioRead, MMIOINFO