Creating a RIFF Chunk

The following example uses the mmioCreateChunkL_VVNA function to create a chunk with a chunk identifier of  RIFF  and a form type of  RDIB .

HMMIO    hmmio;

MMCKINFO mmckinfo;

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mmckinfo.fccType = mmioFOURCC('R', 'D', 'I', 'B');

mmioCreateChunk(hmmio, &mmckinfo, MMIO_CREATERIFF);

If you are creating a  RIFF  or  LIST  chunk, you must specify the form type or list type in the fccType member of the MMCKINFO2NZM4LP structure. In the previous example,  RDIB  is the form type.

If you know the size of the data field in a new chunk, you can set the cksize member of the MMCKINFO structure when you create the chunk. This value will be written to the data size field in the new chunk. If this value is not correct when you call mmioAscendU12GWA to mark the end of the chunk, it will be automatically rewritten to reflect the correct size of the data field.

After you create a chunk by using the mmioCreateChunkL_VVNA function, the file position is set to the data field of the chunk (8 bytes from the beginning of the chunk). If the chunk is a  RIFF  or  LIST  chunk, the file position is set to the location following the form type or list type (12 bytes from the beginning of the chunk).