diff --git a/platform/CXWindowsUtil.cpp b/platform/CXWindowsUtil.cpp
index f7ecb357..60d355bd 100644
--- a/platform/CXWindowsUtil.cpp
+++ b/platform/CXWindowsUtil.cpp
@@ -10,7 +10,7 @@
 bool
 CXWindowsUtil::getWindowProperty(Display* display, Window window,
 				Atom property, CString* data, Atom* type,
-				int* format, bool deleteProperty)
+				SInt32* format, bool deleteProperty)
 {
 	assert(display != NULL);