write eof without closing

[Grant Edwards]

On 2006-08-21, Alex Martelli <aleax at mac.com> wrote:
> Grant Edwards <grante at visi.com> wrote:
>    ...
>> IIRC, ctrl-Z is not used _in_files_ to represent EOF.  Only
>> when text is being entered at the console.
>
> Easy to test, if you have Windows:

I might, but I won't admit it in public. :)

>>>> n='foo.txt'
>>>> s='ba\r\n'+chr(26)+'bo\r\r'
>>>> open(n,'wb').write(s)
>>>> ss=open(n).read()
>>>> ss
> 'ba\n'
>
> As you see, in _text_ files on Windows a control-Z (char(26), AKA
> '\x1a') does indeed represent "end of file" -- a convention going back
> to CP/M (which lacked metadata to represent file length except in
> multiples of 256 characters, if I recall correctly)

That's correct.

> and is still followed by Windows (and by Python running on
> Windows).

Very interesting.  I thought that windows had abandoned that. I
remember having problems under DOS/Windows caused by an old
text editor that put a ctrl-Z at the end of the file --
probably a result of the other programs reading the file in
binary mode and seeing the ctrl-Z.

> Nevertheless I doubt it would help the original poster -- I
> think, like /F and you, that a line-end and flush may be what
> he needs.

-- 
Grant Edwards                   grante             Yow!  Am I elected yet?
                                  at               
                               visi.com