-#define SET_CALLBACK(a) \
- if( fgStructure.Window == NULL ) \
- return; \
- SET_WCB( ( *( fgStructure.Window ) ), a, callback );
+#define SET_CALLBACK(a) \
+do \
+{ \
+ if( fgStructure.Window == NULL ) \
+ return; \
+ SET_WCB( ( *( fgStructure.Window ) ), a, callback ); \
+} while( 0 )