OpenEuphoria

Re: seek() bug?

• Posted by Robert Craig <rds at RapidEuphoria.com> Feb 15, 2002
• 635 views

Derek Parnell writes:
> I can confirm that there is a bug somewhere in Euphoria's handling of
> puts(), gets(), seek(), and where() when using a file opened for either "u"
> or "ub".

OK, Thanks for the example.
I think I see the problem.
Your code and Kat's code seem to be falling into the little trap
that I mentioned in my previous post:
> 3. The Euphoria manual states:
>    "After seeking and reading (writing) a series of bytes, you may
>      need to call seek() explicitly before you switch to writing
>      (reading) bytes, even though the file position should already be
>      what you want."

I discovered this a couple of years ago, and I originally thought it 
was due to some kind of bug in Watcom, but it seems to happen 
with all the C compilers (tested using the Translator).
I'm not doing much in Euphoria, other than passing the seek 
and puts/gets info to the C routines, so it seems to be a quirk in C.

So the rule is: when switching between reading the file and
writing the file, do an explicit seek() to set the file pointer.
I also tried calling flush() and that also works in this case.

Regards,
   Rob Craig
   Rapid Deployment Software
   http://www.RapidEuphoria.com