"readline()" omitted '\r' in win32 for dos format text file

[Newgene]

Hi, group,
I have python2.3 installed on win2k. I noticed that when I open a
dos format text file (eol is '\r\n'), readline() always returns a line
ending with '\n' only, not '\r\n'. While I read the same file on unix,
it returns a line ending with '\r\n' correctly.
This makes me difficult to determine the format of a text file, dos or
unix.

Is this a bug or intended behavior? If not a bug, then how to
determine the format of a text file?

Thanks.

C