diff --git a/format-test.cc b/format-test.cc
index 691f7536..b60515f5 100644
--- a/format-test.cc
+++ b/format-test.cc
@@ -57,7 +57,6 @@
 #  define O_TRUNC _O_TRUNC
 #  define S_IRUSR _S_IREAD
 #  define S_IWUSR _S_IWRITE
-#  define open _open
 #  define close _close
 #  define dup _dup
 #  define dup2 _dup2