This message is sent to a window when waveform data is present in the input buffer and the buffer is being returned to the application. The message can be sent either when the buffer is full, or after the waveInReset function is called.
WORD wParam
Specifies a handle to the waveform input device that received the waveform data.
LONG lParam
Specifies a far pointer to a WAVEHDR structure identifying the waveform data buffer.
None
The returned buffer may not be full. The dwBytesRecorded field of the WAVEHDR structure specified by lParam will specify the number of bytes recorded into the buffer.
WIM_DATA