[fpc-pascal] Issue 0012528: TFPList exception with no excpetion stack printed

[cobines]

2011/1/28  <michael.vancanneyt at wisa.be>:
>
>
> On Fri, 28 Jan 2011, cobines wrote:
>
>> Hello,
>>
>> Can someone comment on this issue? It still exists in current FPC
>> trunk. It seems the patch posted there fixes the issue. Is the patch
>> not good?
>
> The patch is good, but I suspect a more general patch is needed.

Meaning there is an issue with "raise at addr" but not with "raise" or
"raise at addr, frame" ?

There are other places in RTL that use "raise at addr, frame" so maybe
these few places which use "raise at addr" can be changed, at least as
a temporary solution, until a more general patch, as you say, is
produced.

>
>>
>> Why is "raise ... at" needed instead of just "raise" ?
>
> Because if you use 'Raise', then the .error method shows up in the stack
> dump, when the real location is actually in the frame above. It's not
> actually required, but it is nicer to have the real location as the first
> frame in your stack list.
>

OK, I see now, thanks.

I looked at fpc_PushExceptObj and it uses frame pointers to create
backtrace, so is there a point in calling "raise at addr" with
frameptr=nil? Is sometimes frame pointer not possible to retrieve that
such construct is allowed?

--
cobines