[fpc-pascal] Re: Fpc Access Violation if AppConfigDir doesn't exist.

Giuliano Colla giuliano.colla at fastwebnet.it
Tue Feb 12 15:24:34 CET 2013

On 02/12/2013 02:46 PM, Mark Morgan Lloyd wrote:
> Giuliano Colla wrote:
>> On 02/12/2013 10:02 AM, Mark Morgan Lloyd wrote:
>>> I admit that I was slightly trolling there, since Giuliano was 
>>> complaining about exceptions that he wasn't seeing (because, it 
>>> turns out, he wasn't catching them).
>> You catch an exception if you can handle it. If a user for some 
>> reasons has write-protected a configuration file, there's nothing the 
>> application can do about it. One can usually rely on the system 
>> default exception handler to show the error message. If it doesn't 
>> happen, then there's something wrong somewhere.
> Yes, but the point that I'm trying to get across is that the earlier 
> you make sure that you've got full access to the files (i.e. all 
> directories in the path exist, the file either exists and is writable 
> or you create it from a template) the easier you make life for 
> yourself. If having the file is absolutely essential then check for it 
> before you even open the main form and bomb if it's obvious that 
> there's a problem.

That's the point. The configuration file in this application is useful 
but not essential. It holds fine calibration data for a set of remote 
sensors. If you can't read it, you must click again on the "Calibrate" 
button a number of times, to display more precise values. One could even 
chose to write-protect it, to avoid overwriting a good calibration.
It's not a DataBase application where if you don't set the right 
hostname, user and password you can't do a thing.
That's why I would have been perfectly happy with a default system error 
box telling "write error", or whatever, just to let know that the data 
have not been saved.
What happens on the contrary is that, in case of failure, no error is 
shown, and, what's more annoying, that the form can't be closed, which 
can be quite confusing for a normal user.


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