diff -r 3f754be7abbb -r 4e836769d93c mercurial/util.py
--- a/mercurial/util.py	Thu Mar 20 15:59:54 2008 -0500
+++ b/mercurial/util.py	Thu Mar 20 22:41:40 2008 +0100
@@ -1000,7 +1000,8 @@
         pass
 
     def set_binary(fd):
-        msvcrt.setmode(fd.fileno(), os.O_BINARY)
+        if hasattr(fd, 'fileno'):
+            msvcrt.setmode(fd.fileno(), os.O_BINARY)
 
     def pconvert(path):
         return '/'.join(splitpath(path))