MMIOINFO

The MMIOINFO structure contains the current state of a file opened by using the mmioOpen function.

typedef struct { 
    DWORD      dwFlags; 
    FOURCC     fccIOProc; 
    LPMMIOPROC pIOProc; 
    UINT       wErrorRet; 
    HTASK      hTask; 
    LONG       cchBuffer; 
    HPSTR      pchBuffer; 
    HPSTR      pchNext; 
    HPSTR      pchEndRead; 
    HPSTR      pchEndWrite; 
    LONG       lBufOffset; 
    LONG       lDiskOffset; 
    DWORD      adwInfo[4]; 
    DWORD      dwReserved1; 
    DWORD      dwReserved2; 
    HMMIO      hmmio; 
} MMIOINFO;

Members

dwFlags

Flags specifying how a file was opened. The following values are defined:

MMIO_ALLOCBUF: File's I/O buffer was allocated by the mmioOpen or mmioSetBuffer function.
MMIO_CREATE: The mmioOpen function was directed to create the file (or truncate it to zero length if it already existed).
MMIO_DIRTY: The I/O buffer has been modified.
MMIO_EXIST: Checks for the existence of the file.
MMIO_GETTEMP: A temporary name was retrieved by the mmioOpen function.
MMIO_PARSE: The new file's path is returned.

The following values may be set when the file is opened in share mode (identified by using the MMIO_SHAREMODE bit mask):

MMIO_COMPAT: File was opened with compatibility mode, allowing any process on a given machine to open the file any number of times.
MMIO_DENYNONE: Other processes are not denied read or write access to the file.
MMIO_DENYREAD: Other processes are denied read access to the file.
MMIO_DENYWRITE: Other processes are denied write access to the file.
MMIO_EXCLUSIVE: Other processes are denied read and write access to the file.

The following values may be set when the file is opened in read/write mode (identified by using the MMIO_RWMODE bit mask):

MMIO_READ: File was opened only for reading.
MMIO_READWRITE: File was opened for reading and writing.
MMIO_WRITE: File was opened only for writing.

fccIOProc

Four-character code identifying the file's I/O procedure. If the I/O procedure is not an installed I/O procedure, this member is NULL.

pIOProc

Address of file's IO procedure.

wErrorRet

Extended error value from the mmioOpen function if it returns NULL. This member is not used to return extended error information from any other functions.

hTask

Handle of a local I/O procedure. Media Control Interface (MCI) devices that perform file I/O in the background and need an I/O procedure can locate a local I/O procedure with this handle.

cchBuffer

Size, in bytes, of the file's I/O buffer. If the file does not have an I/O buffer, this member is zero.

pchBuffer

Address of the file's I/O buffer. If the file is unbuffered, this member is NULL.

pchNext

Address of the next location in the I/O buffer to be read or written. If no more bytes can be read without calling the mmioAdvance or mmioRead function, this member points to the pchEndRead member. If no more bytes can be written without calling the mmioAdvance or mmioWrite function, this member points to the pchEndWrite member.

pchEndRead

Address of the location that is 1 byte past the last location in the buffer that can be read.

pchEndWrite

Address of the location that is 1 byte past the last location in the buffer that can be written.

lBufOffset

Reserved.

lDiskOffset

Current file position, which is an offset, in bytes, from the beginning of the file. I/O procedures are responsible for maintaining this member.

adwInfo

State information maintained by the I/O procedure. I/O procedures can also use these members to transfer information from the application to the I/O procedure when the application opens a file.

dwReserved1

Reserved.

dwReserved2

Reserved.

hmmio

Handle of the open file, as returned by the mmioOpen function. I/O procedures can use this handle when calling other multimedia file I/O functions.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in mmsystem.h.

MMIOINFO

Members

QuickInfo

See Also