int ImagingLibTiffSetField(ImagingCodecState state, ttag_t tag, ...){
	// after tif_dir.c->TIFFSetField.
	TIFFSTATE *clientstate = (TIFFSTATE *)state->context;
	va_list ap;
	int status;

	va_start(ap, tag);
	status = TIFFVSetField(clientstate->tiff, tag, ap);
	va_end(ap);
	return status;
}
Unknown