[fpc-devel] Re: Debugger for FPC

Vincent Snijders vsnijders at vodafonevast.nl
Thu Mar 12 10:13:02 CET 2009

Jonas Maebe schreef:
> Vincent Snijders wrote on do, 12 mrt 2009:
>> I guess the fpc developers traded debuggability for maintainability, so
>> you could have a better fpc (more features or less bugs). That is what
>> it concerns to you as developer. Maybe you disagree with that trade off.
> No, it's simply an unimplemented feature. In fact, I for one didn't even 
> realise that absolute variables were not included in the debug 
> information (they're not used that much in the compiler itself).

I was referring to the fact that the FPC RTL uses an absolute variable

    { Character to be put between date, month and year }
    DateSeparator: char absolute DefaultFormatSettings.DateSeparator;

instead of just
   DateSepator: char.

I speculated that is was to have more maintainable code, so. The 
drawback is that you cannot view the contents, because the compiler 
doesn't seem to generate the correct debug info for it (yet).

Apparently this trade off has been made unconsciously.

> I've also never seen a bug report about this fact. And although I 
> realise that it may not be obvious that some variable is not visible due 
> to the fact that it's an absolute variable, simply a bug report about 
> "variable x of unit y is not visible to the debugger" would have been 
> enough.

Who volunteers to create it?

> So when something does not work in the debugger, do not automatically 
> assume that it's because GDB is supposedly so bad. It may just as well 
> be a bug in the compiler.

I did not, it was clear from earlier posts, that it the compiler doesn't 
  write out this information (yet). OTOH, I did not know this a week ago 
and would have blamed Lazarus' interface with the debugger. ;-)


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