[fpc-pascal] How to analyze a core dump?

[Luca Olivetti]

En/na Vincent Snijders ha escrit:
> On Wed, 27 Jun 2007 19:38:03 +0200
> Luca Olivetti <luca at ventoso.org> wrote:
> 
>> En/na Luca Olivetti ha escrit:
>>> En/na Cesar Romero ha escrit:
>>>> Where S is initialized?
>>>> I only see L initialized.
>>>>
>>>> []s
>>>>
>>>>
>>>> Cesar Romero
>>>>> 442:  L:=length(s);
>>>>> 443:  if L<1 then exit;
>>>>> 444:  case s[1] of
>>>>>
>>>>> so I can't see how it could possibly be uninitialized.
>>> nothwithstanding the fact that if length(s)<1 line 444 won't be 
>>> executed, so the "uninitialized" should be flagged in line 442, I know 
>>> that this chunk is inside
>>>
>>> procedure TButlerPhone.Receive(s: string);
>>>
>>> so s is a parameter.
>>> This procedure is called exclusively from
>>>
>>> procedure TStatusThread.Receive;
>>> begin
>>>   FOwner.Receive(FData)
>>> end;
>>>
>>> (FOwner is a TButlerPhone)
>>>
>>> which in turn is called only here:
>>>
>>>           FData:=copy(buffer,i+2,L-1);
>>>           if buffer[i+L+1]=checksum(FData) then
>>>           begin
>>>            if not terminated then synchronize(@Receive);
>>>           end else
>>>
>> And another writeln confirms that L is 1 when valgrind complains, so the 
>> string is definitely initialized.
> 
> Did you write to that string or merely set its length using SetLength?

The string was passed as a value parameter, coming from fdata:


FData:=copy(buffer,i+2,L-1) (buffer is a static array of char, FData is 
a string, field of the class)

if buffer[i+L+1]=checksum(FData) then
   synchronize(@receive) ----->

TStatusThread.Receive;
begin
   FOwner.Receive(FData)


procedure TButlerPhone.Receive(s: string);
....
   L:=length(s);
   writeln('>>>>>>>>>>>>>>>>>>>>>>> ',L);  ---> to confirm, and it's 
always >0
   if L<1 then exit;
   case s[1] of  --> here valgrind complains




Anyway, I doubt the problems is here, it only strikes me that valgrind 
complains.

Bye
-- 
Luca