[stdlib-sig] socket.makefile() questions

[tim at ksu.edu]

My apologies if this message is to the wrong group.

I have been experimenting with socket.makefile()from Python 3.1.1.  I have not had much difficulty reading from the returned file object, but I don't understand the behavior when trying to write (send on the socket).  I'm hoping that someone can explain how this is supposed to work.

I find that this works for an established connection on socket s:
fd = s.makefile('wb', buffering = 0)
fd.write("This is a test message\n".encode('ascii'))

A mode of 'rwb' also works.  The object fd is of type SocketIO.

fd = s.makefile('w', buffering = 0) -> ValueError exception
fd = s.makefile('w') -> io.BufferedWriter, which does not send data.
fd = s.makefile('wb') -> io.TextIOWrapper, which does not send data.

The default value of the "buffering" parameter is None, which from my testing has a different result than 0 (zero).

So, questions:
1) Why does buffering = None result in a buffered file object?
2) Are there bugs or incomplete work with socket.makefile(), io.BufferedWriter and io.TextIOWrapper in terms of why the latter two objects are returned, but fail to send data?
  
Thank you,
--
Tim Bower
Assistant Professor
Kansas State University at Salina
Computer Systems Technology

tim at ksu.edu