Seems weird it supports the following type but not CV_32S

CvFloodFillFunc [[CvFloodFillFunc]] func = type == CV_8UC1 || type == CV_8UC3 ? (CvFloodFillFunc)icvFloodFill_8u_CnIR : type == CV_32FC1 || type == CV_32FC3 ? (CvFloodFillFunc)icvFloodFill_32f_CnIR : 0;

I got around this by using CV_32FC1 and casting to (int) where required.