Index: src/infix2rpn.hxx
--- src/infix2rpn.hxx.orig
+++ src/infix2rpn.hxx
@@ -62,8 +62,8 @@ class INFIX2RPN { (public)
 private:
 	void ProcessOp(const operators op, STRSTACK *TheStack,  STRING *result);
 	void RegisterError(const STRING &Error);
-	CHR *op2string(const operators op);
-	CHR *StandardizeOpName(const STRING op);
+	const char* op2string(const operators op);
+	const char* StandardizeOpName(const STRING op);
 	INT TermsWithNoOps;
 	STRING ErrorMessage;