Avoid unnecessary string copies

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 3aae9f1c6ec3d337d5a9c953e5e528cf3a341439..6db977a4c7e2c636c82b4417b423daf0c2203470 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -89,7 +89,7 @@ namespace Eval {
     vector<string> dirs = { "<internal>" , "" , CommandLine::binaryDirectory };
     #endif
 
-    for (string directory : dirs)
+    for (const string& directory : dirs)
         if (currentEvalFileName != eval_file)
         {
             if (directory != "<internal>")