Use #ifndef instead of #if !defined

[stockfish] / src / book.h

diff --git a/src/book.h b/src/book.h
index ed446636c8a45359489b61c345fe00aeb9b9fec2..4ce74f471fddddfdef74b710e6de15153ac89d93 100644 (file)
--- a/src/book.h
+++ b/src/book.h
@@ -17,7 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#if !defined(BOOK_H_INCLUDED)
+#ifndef BOOK_H_INCLUDED
 #define BOOK_H_INCLUDED
 
 #include <fstream>
@@ -42,4 +42,4 @@ private:
   std::string fileName;
 };
 
-#endif // !defined(BOOK_H_INCLUDED)
+#endif // #ifndef BOOK_H_INCLUDED