X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsan.cpp;h=2d5dca3fbf94682bfdb2625c562358a9d871d244;hp=f155887809f6cccca81d672de3c52f674ba6fa50;hb=d844a75d2c12e4888443e47cb7b0effd78d81bb8;hpb=c5e71f515045029f4d89f1302277217b878fa7a4

diff --git a/src/san.cpp b/src/san.cpp
index f1558878..2d5dca3f 100644
--- a/src/san.cpp
+++ b/src/san.cpp
@@ -63,7 +63,7 @@ namespace {
 /// that the move is a legal move from the position. The return value is
 /// a string containing the move in short algebraic notation.
 
-const string move_to_san(const Position& pos, Move m) {
+const string move_to_san(Position& pos, Move m) {
 
   assert(pos.is_ok());
   assert(move_is_ok(m));
@@ -123,10 +123,10 @@ const string move_to_san(const Position& pos, Move m) {
   // Position::move_is_check doesn't detect all checks (not castling moves,
   // promotions and en passant captures).
   StateInfo st;
-  Position p(pos);
-  p.do_move(m, st);
-  if (p.is_check())
-      san += p.is_mate()? "#" : "+";
+  pos.do_move(m, st);
+  if (pos.is_check())
+      san += pos.is_mate() ? "#" : "+";
+  pos.undo_move(m);
 
   return san;
 }