Use mmioGetInfo to obtain information about a file I/O buffer, such as the buffer size and address. The mmioGetInfo function also sets up a file for direct I/O buffer manipulation.

The mmioGetInfo function identifies a pointer to an MMIOINFO structure that mmioGetInfo fills with information about the file I/O buffer. The return value is 0 if the operation is successful; otherwise, the return value specifies an error code.