This looks like it's always been backwards.

diff --git a/tornado/platform/windows.py b/tornado/platform/windows.py
index f3efa8e8929c876d53708b87f1cb69958fc6633d..7e8bedc2c2e84a7a1ee92f2dc4afaf543968a244 100644 (file)
--- a/tornado/platform/windows.py
+++ b/tornado/platform/windows.py
@@ -39,7 +39,7 @@ def fcntl(fd, op, arg=0):
     elif op == F_SETFD:
         # Check that the flag is CLOEXEC and translate
         if arg == FD_CLOEXEC:
-            success = SetHandleInformation(fd, HANDLE_FLAG_INHERIT, arg)
+            success = SetHandleInformation(fd, HANDLE_FLAG_INHERIT, 0)
             if not success:
                 raise ctypes.GetLastError()
         else: