MMCKINFO structure

The MMCKINFO structure contains information about a chunk in a RIFF file.


typedef struct {
  FOURCC ckid;
  DWORD  cksize;
  FOURCC fccType;
  DWORD  dwDataOffset;
  DWORD  dwFlags;


  • ckid
    Chunk identifier.

  • cksize
    Size, in bytes, of the data member of the chunk. The size of the data member does not include the 4-byte chunk identifier, the 4-byte chunk size, or the optional pad byte at the end of the data member.

  • fccType
    Form type for "RIFF" chunks or the list type for "LIST" chunks.

  • dwDataOffset
    File offset of the beginning of the chunk's data member, relative to the beginning of the file.

  • dwFlags
    Flags specifying additional information about the chunk. It can be zero or the following flag:

    Name Description

    The length of the chunk might have changed and should be updated by the mmioAscend function. This flag is set when a chunk is created by using the mmioCreateChunk function.



Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]


Mmsystem.h (include Windows.h)

See also