UINT APIENTRY
mciDriverYield (
MCIDEVICEID wDeviceID
);
The mciDriverYield function calls the application’s yield function. The yield function checks to see if the user has pressed the break key.
Returns the value returned from the yield function. If the break key was pressed, the return value should be a nonzero value. Otherwise returns zero.
Drivers call mciDriverYield while waiting for a requested operation to complete, if the application included the MCI_WAIT flag with the command. See Handling the MCI_WAIT Flag.