Fix compile error with MSVC 2013

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index 447872ab2e40c2c7521ee923c387d9a91212a374..86acd20d0eb7a174b779147f8e992dce9ff4a7c5 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -175,7 +175,7 @@ public:
   Value non_pawn_material(Color c) const;
 
   // Position consistency check, for debugging
-  bool pos_is_ok(int* step = NULL) const;
+  bool pos_is_ok(int* step = nullptr) const;
   void flip();
 
 private: