diff --git a/src/util.cpp b/src/util.cpp
index d3d7dfef585..8e4c5a719bd 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -7177,7 +7177,7 @@ void addCodeOnlyMappings()
   updateLanguageMapping(".sql",   "sql");
 }
 
-SrcLangExt getLanguageFromFileName(const QCString fileName)
+SrcLangExt getLanguageFromFileName(const QCString& fileName)
 {
   int i = fileName.findRev('.');
   if (i!=-1) // name has an extension
diff --git a/src/util.h b/src/util.h
index dd2f3aa2377..2f362fd6768 100644
--- a/src/util.h
+++ b/src/util.h
@@ -384,7 +384,7 @@ QCString stripLeadingAndTrailingEmptyLines(const QCString &s,int &docLine);
 //                         const QCString &anchor="");
 
 bool updateLanguageMapping(const QCString &extension,const QCString &parser);
-SrcLangExt getLanguageFromFileName(const QCString fileName);
+SrcLangExt getLanguageFromFileName(const QCString& fileName);
 void initDefaultExtensionMapping();
 void addCodeOnlyMappings();