-extern InstrPtr disInstr ( StgBCO *bco, InstrPtr pc );
-extern void disassemble( StgBCO *bco, char* prefix );
+#ifndef DISASSEMBLER_H
+#define DISASSEMBLER_H
+
+#ifdef DEBUG
+
+extern int disInstr ( StgBCO *bco, int pc );
+extern void disassemble( StgBCO *bco );
+
+#endif
+
+#endif /* DISASSEMBLER_H */