Re: Checking the existence of a file

Try:
www.bombjack.org they have tons of .pdfs of old Commodore books.
-Terry Raymond

On Tuesday, March 1, 2016, <silverdr@wfmh.org.pl> wrote:

>
> > On 2016-03-01, at 14:26, Baltissen, GJPAA (Ruud) <ruud.baltissen@apg.nl
> <javascript:;>> wrote:
> >
> > Hallo allemaal,
> >
> >
> > Although I have written a lot in ML, I cannot remember to have written a
> PRG in ML for any Commodore ever. My problem: how can I check the existence
> of a file? As shown in a Data-Becker book I did set various variables like
> filename and the length of it using a standard routine, set the logical
> file number, device number and secondary address using a standard routine
> and called the OPEN routine. This Data-Becker book said that if things go
> wrong, the Carry is set and A contains the error code, including one for
> 'file is missing'. Seemed simple enough.
> >
> > I tested the routine by entering a non-existing name but after OPEN the
> Carry is clear (thus file exists IMHO),
>
> AFAIR OPEN() doesn't do anything except assigning the entry in the LAT
> table and checking the presence of the device. It would return error in
> cases like when it couldn't assign the table entry (too many open files,
> device not present, etc.).
>
> It doesn't check the actual existence of the file you try to OPEN() so it
> won't report this correctly back to you. I recall doing the very same thing
> a few you try to do now many times times but I need to fetch my sources to
> recall how I eventually did it in a simple and reliable way.
>
> --
> SD!
>
>
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>


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