diff --git a/headers/os/app/Message.h b/headers/os/app/Message.h
index d406a45814..2920a1a3a2 100644
--- a/headers/os/app/Message.h
+++ b/headers/os/app/Message.h
@@ -376,7 +376,7 @@ class BMessage {
 
 		enum			{ sNumReplyPorts = 3 };
 		static port_id	sReplyPorts[sNumReplyPorts];
-		static long		sReplyPortInUse[sNumReplyPorts];
+		static int32	sReplyPortInUse[sNumReplyPorts];
 		static int32	sGetCachedReplyPort();
 
 		static BBlockCache* sMsgCache;
diff --git a/src/kits/app/Message.cpp b/src/kits/app/Message.cpp
index 8cc5c4049a..1e8c5e46f9 100644
--- a/src/kits/app/Message.cpp
+++ b/src/kits/app/Message.cpp
@@ -78,7 +78,7 @@ extern "C" {
 
 BBlockCache *BMessage::sMsgCache = NULL;
 port_id BMessage::sReplyPorts[sNumReplyPorts];
-long BMessage::sReplyPortInUse[sNumReplyPorts];
+int32 BMessage::sReplyPortInUse[sNumReplyPorts];
 
 
 template<typename Type>