diff --git a/src/include/interface.h b/src/include/interface.h
index 6c71ec7a7..9562cb1b3 100644
--- a/src/include/interface.h
+++ b/src/include/interface.h
@@ -349,9 +349,9 @@ extern void DrawMessages();
 	/// Draw the player resource in resource line
 extern void DrawResources();
 	/// Set message to display
-extern void SetMessage(const char *fmt, ...);
+extern void SetMessage(const char *fmt, ...) PRINTF_VAARG_ATTRIBUTE(1, 2);
 	/// Set message to display with event point
-extern void SetMessageEvent(int x, int y, const char *fmt, ...);
+extern void SetMessageEvent(int x, int y, const char *fmt, ...) PRINTF_VAARG_ATTRIBUTE(3, 4);
 	/// Center view-point on last event message
 extern void CenterOnMessage();
 	/// Cleanup all messages
diff --git a/src/include/iolib.h b/src/include/iolib.h
index cc8f732fa..52ea30f61 100644
--- a/src/include/iolib.h
+++ b/src/include/iolib.h
@@ -68,7 +68,7 @@ class FileWriter
 public:
 	virtual ~FileWriter() {}
 
-	void printf(const char *format, ...);
+	void printf(const char *format, ...) PRINTF_VAARG_ATTRIBUTE(2, 3); // Don't forget to count this
 
 	virtual int write(const char *data, unsigned int size) = 0;
 };
@@ -113,7 +113,8 @@ public:
 	int read(void *buf, size_t len);
 	int seek(long offset, int whence);
 	long tell();
-	int printf(const char *format, ...);
+
+	int printf(const char *format, ...) PRINTF_VAARG_ATTRIBUTE(2, 3); // Don't forget to count this
 
 private:
 	int   cl_type;   /// type of CFile
diff --git a/src/include/player.h b/src/include/player.h
index 77db44a6f..a2e2af119 100644
--- a/src/include/player.h
+++ b/src/include/player.h
@@ -402,7 +402,7 @@ public:
 	int HaveUnitTypeByIdent(const std::string &ident) const;
 
 	/// Notify player about a problem
-	void Notify(int type, int x, int y, const char *fmt, ...) const;
+	void Notify(int type, int x, int y, const char *fmt, ...) const PRINTF_VAARG_ATTRIBUTE(5, 6); // Don't forget to count this
 
 	/**
 	**  Check if the player index is an enemy
diff --git a/src/include/stratagus.h b/src/include/stratagus.h
index 5c1667c38..775e103fa 100644
--- a/src/include/stratagus.h
+++ b/src/include/stratagus.h
@@ -97,6 +97,14 @@
 #define UNUSED(var) (var)
 #endif
 
+#ifdef __GNUC__
+#define PRINTF_VAARG_ATTRIBUTE(a, b) __attribute__((format (printf, a, b)))
+#else
+#define PRINTF_VAARG_ATTRIBUTE(a, b)
+#endif
+
+
+
 /*============================================================================
 ==  Debug definitions
 ============================================================================*/
@@ -276,7 +284,7 @@ extern void DrawMapArea();              /// Draw the map area
 extern void GameMainLoop();             /// Game main loop
 
 	/// Show load progress
-extern void ShowLoadProgress(const char *fmt, ...);
+extern void ShowLoadProgress(const char *fmt, ...) PRINTF_VAARG_ATTRIBUTE(1, 2);
 
 struct DisplayAutoLocker {
 	DisplayAutoLocker();
diff --git a/src/unit/unit_manager.cpp b/src/unit/unit_manager.cpp
index 64be01d10..f070bd0af 100644
--- a/src/unit/unit_manager.cpp
+++ b/src/unit/unit_manager.cpp
@@ -126,7 +126,7 @@ void CUnitManager::Save(CFile *file)
 
 	std::list<CUnit *>::iterator it = ReleasedUnits.begin();
 	for (; it != ReleasedUnits.end(); ++it) {
-		file->printf(", {Slot = %d, FreeCycle = %lu}", (*it)->Slot, (*it)->Refs);
+		file->printf(", {Slot = %d, FreeCycle = %u}", (*it)->Slot, (*it)->Refs);
 	}
 	file->printf(")\n");
 }