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Re: upload: diffstat-1.40-1, tar-1.15.1-1


On Wed, 17 Aug 2005, Eric Blake wrote:

> > >I'm not sure this is correct.  fopen(..., "rt") should create LF endings
> > >on binary mounts and CRLF on text mounts...  IIUC, the open mode is a hint
> > >to the underlying filesystem whether line ending translation should be
> > >done -- the actual translation is done based on the mount type.
> >
> > Opening with "rt" bypasses the underlying mount type.  And, it only
> > opens the file for read.
>
> But opening with "rt" is non-POSIX, while opening with "r" or "rb" is
> POSIX, so the upstream maintainers are more reluctant to accept
> a patch that uses "rt".  I have never seen any standards documentation
> that describes what "rt" should do, so I assumed that it forced
> opening a file in text mode (ie. all \r\n in the file are collapsed to
> \n to the application reading the file, regardless of the mount point
> of the file).  It sounds like you are telling me my assumption was
> wrong, and that "rt" on a binary mount point preserves \r?

That's what I was saying, but I was confused.  Chris said that text mode
always forces CRLF->LF conversion on reads and LF->CRLF conversion on
writes.

The fact that there are no standards for O_TEXT or "rt"/"wt" didn't help
my confusion any.

It seems that "wt" is rather useless, then.  If one wanted to always
produce a file with CRLF line endings, she'd open it with O_BINARY and use
"\r\n" sequences for line endings.

In any case, "rt"/"wt" should be equivalent to O_TEXT...

> Maybe we need an update to
> http://cygwin.com/cygwin-ug-net/using-textbinary.html

Yes, it does say "there is no direct way to specify text mode in an
fopen() call", doesn't it?
	Igor
-- 
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