diff --git a/common/string_util.h b/common/string_util.h
index 3d2db3f8d..c69f01456 100644
--- a/common/string_util.h
+++ b/common/string_util.h
@@ -51,6 +51,6 @@ uint64 hextoi64(const char* num);
 
 void MakeLowerString(const char *source, char *target);
 void RemoveApostrophes(std::string &s);
-void find_replace(std::string& string_subject, std::string& search_string, std::string& replace_string);
+void find_replace(std::string& string_subject, const std::string& search_string, const std::string& replace_string);
 
 #endif