Mail Archives: cygwin/2004/11/04/14:44:20
> -----Original Message-----
> From: cygwin-owner On Behalf Of Christopher Faylor
> Sent: 04 November 2004 19:05
> On Thu, Nov 04, 2004 at 06:52:03PM -0000, Dave Korn wrote:
> >> -----Original Message-----
> >> From: cygwin-owner On Behalf Of Earl Chew
> >> Sent: 04 November 2004 18:40
> >> The problem appears to be related to a change in Perl, rather
> >> than Cygwin.
> >
> > ....or maybe a change in 'od' ?
>
> Hard to see how "od" would take previous versions of perl
> into account.
Well, yes, that would be magic of it.
I guess it's my own fault for not explicitly using smilies.
> >dk AT mace /win/textmode/c> od -c foo.txt
> >0000000 H e l l o \n
> >0000006
> >dk AT mace /win/textmode/c> od -c < foo.txt
> >0000000 H e l l o \r \n
> >0000007
> >dk AT mace /win/textmode/c>
> >
> > I wouldn't like to jump to *any* hasty conclusions about
> whether or not I
> >know what the _actual_ contents of this file are just by
> looking at it with
> >od........
>
> The OP showed consistent behavior using od and different
> versions of perl.
> There is no reason to speculate about od problems in this scenario.
The fact that od was involved was a detail; the actual point I was making
was just about the complications of diagnosing a problem like this when
there are multiple interactions between file modes and mountpoints and in
particular when those interactions also affect the tools being used as
diagnostics. It was a fairly generic point about debugging in general.
Perl and od just happened to be the first handy candidates. It wasn't
"speculating about od problems".
> setmode() should trump everything. If a program calls setmode() on an
> open file descriptor, future operations on that file should honor what
> setmode() says.
Yes, but as I was pointing out, no matter what effect setmode might or
might not have had on the contents of the file when perl wrote it out to
disk, there's a whole secondary stage of processing when od opens the file
and reads it back in, interacting with the shell's stdio handling, and that
secondary stage may (or may not; but we can't just _assume_) involve a
non-null transformation of the data under analysis.
cheers,
DaveK
--
Can't think of a witty .sigline today....
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