The following example uses the mmioDescend function to search for a "RIFF" chunk with a form type of "WAVE" to verify that the file that has just been opened is a waveform-audio file.
HMMIO hmmio;
MMCKINFO mmckinfoParent;
MMCKINFO mmckinfoSubchunk;
.
.
.
// Locate a "RIFF" chunk with a "WAVE" form type to make
// sure the file is a waveform-audio file.
mmckinfoParent.fccType = mmioFOURCC('W', 'A', 'V', 'E');
if (mmioDescend(hmmio, (LPMMCKINFO) &mmckinfoParent, NULL,
MMIO_FINDRIFF))
// The file is not a waveform-audio file.
else
// The file is a waveform-audio file