Re: Error while opening a .txt file

[Markus Mützel]

Am 07. Juni 2020 um 14:57 Uhr schrieb "N":
> On Sun, 7 Jun 2020 14:46:58 +0200
> Markus Mützel <markus.muetzel@gmx.de> wrote:
> 
> > Am 07. Juni 2020 um 14:37 Uhr schrieb "Andrew Janke":
> > > Or onCleanup! It can make your code really concise.
> > > 
> > > file = 'data.txt';
> > > [fid, msg] = fopen(file, 'r');
> > > if fid == -1
> > >   error('Failed opening file ''%s'': %s', file, msg);
> > > end
> > > RAII.fid = onCleanup(@() fclose(fid));  % automatically gets called when
> > > RAII is cleared
> > > data = textscan (fid, '% f', 'HeaderLines', 5);
> > > period_arr = data {1};
> > > % and that's it! no try/catch needed
> > > 
> > > Cheers,
> > > Andrew
> > > 
> > 
> > Or that.
> > But keep in mind that this might not work in scripts unless you explicitly 
> > clear the object returned by onCleanup when you are done.
> > 
> > Markus
> 
> If it does not get automatically cleared then function exit this must be a 
> problem. Or?
> 

I don't understand what you are trying to say.
"onCleanup" always works "as expected" in functions.
When used in scripts, the object returned by it might not get out of scope when 
the script finishes executing. Hence you might need to explicitly clear the 
onCleanup variable.

> Think files are closed automatically in C but not in Octave if I got it right.
> 

I don't know what you are trying to say with that either. I can't even guess... 
:-)

Markus