diff --git a/Utils/FileUtils.h b/Utils/FileUtils.h
index ecb4a00..82e3c5e 100644
--- a/Utils/FileUtils.h
+++ b/Utils/FileUtils.h
@@ -72,7 +72,7 @@ namespace Utils {
             #endif
         }
 
-        char* file_extension (char *filename)
+        const char* file_extension (char *filename)
         {
             char *dot = strrchr(filename, '.');
 
@@ -116,4 +116,4 @@ namespace Utils {
     }
 }
 
-#endif
\ No newline at end of file
+#endif