This message is sent to an I/O procedure by mmioSeek to request that the current file position be moved.
LONG lParam1
Specifies the new file position according to the option flag specified in lParam2.
LONG lParam2
Specifies how the file position is changed. Only one of the following flags c an be specified:
SEEK_SET
Move the file position to be lParam1 bytes from the beginning of the file.
SEEK_CUR
Move the file position to be lParam1 bytes from the current position. lParam1 may be positive or negative.
SEEK_END
Move the file position to be lParam1 bytes from the end of the file.
The return value is the new file position. If there is an error, the return value is -1.
The I/O procedure is responsible for maintaining the current file position in the lDiskOffset field of the MMIOINFO structure.
mmioSeek