Message 130042 - Python tracker

Indeed, Python3.1 fails with the -u option.

Before r87824, the C call to write() performed CRLF conversion.  In the implementation of MSVCRT, a local buffer is used (1025 chars in vs8.0, 5*1024 in vs10.0), so WriteFile is called with small sizes.
Since r87824 (or with -u), no such conversion occurs, and WriteFile is called with the full buffer.