On Mon, 5 Jul 2010 16:51:54 -0300
Marcos Douglas m...@delfire.net wrote:
Why I ask this:
If not exists the variable obj2 in call obj1.createObj will happen a
memory leak, right? Because there is not variable to release.
Do you mean using a function as a statement? (for its so-called
On 5 July 2010 23:17, Michael Van Canneyt wrote:
I would even add to this that you need to guard for exceptions:
A:=TSomeClass.Create;
try
// do stuff
finally
A.Free; Make sure it is freed, even in case of exception.
end;
Wouldn't it be nice if we had a try..except..finally statement
In our previous episode, Graeme Geldenhuys said:
Wouldn't it be nice...
Ah, the kiss-of-death phrase for a new feature request :-)
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On Tue, 6 Jul 2010, Graeme Geldenhuys wrote:
On 5 July 2010 23:17, Michael Van Canneyt wrote:
I would even add to this that you need to guard for exceptions:
A:=TSomeClass.Create;
try
// do stuff
finally
A.Free; Make sure it is freed, even in case of exception.
end;
Wouldn't it be
On 07/01/2010 05:46 AM, Simon Webster wrote:
Dear Free Pascallers,
I'm wanting to convert a Turbo Pascal program to fpc, to run
(ultimately) under linux, although I'm actually developing on a mac,
and using virtualbox to run ubuntu. The program in question is a
relatively large non OOP program
On Mon, Jul 5, 2010 at 6:06 PM, Graeme Geldenhuys
graemeg.li...@gmail.com wrote:
On 5 July 2010 22:03, Marcos Douglas wrote:
The ask is:
If a function creates, inside, a object and there is no variable to
receive this pointer, will happen a memory leak?
Yes you will have a memory leak. Easy
On Mon, Jul 5, 2010 at 9:07 PM, Reimar Grabowski reimg...@web.de wrote:
On Mon, 5 Jul 2010 16:51:54 -0300
Marcos Douglas m...@delfire.net wrote:
What do you mean a function has effects is already bad?
A function/procedure always has effects, don't?
IMHO he means that a function should only
obj1:=TMyObject.Create;
Try
obj2:=TMyObject.Create;
Try
Obj1.DoSomething1;
Obj2.DoSomething2;
Finally
FreeAndNil(Obj2);
end;
Finally
FreeAndNil(Obj1);
end;
Hum... I do not agree. Why not this? See..
obj1:=TMyObject.Create;
obj2:=TMyObject.Create;
Try
On Tue, Jul 6, 2010 at 3:05 AM, spir denis.s...@gmail.com wrote:
The object Parser creates obj through the line string.
If the *line* is broke, Parser do not can create an object and an
Exception is created; the *obj* never is nil because there are
exception handling.
I do not see the
On Tue, Jul 6, 2010 at 9:22 AM, Michael Van Canneyt
mich...@freepascal.org wrote:
On Tue, 6 Jul 2010, Graeme Geldenhuys wrote:
On 5 July 2010 23:17, Michael Van Canneyt wrote:
I would even add to this that you need to guard for exceptions:
A:=TSomeClass.Create;
try
// do stuff
finally
On Tue, Jul 6, 2010 at 12:10 PM, Andrew Brunner
andrew.t.brun...@gmail.com wrote:
Hum... I do not agree. Why not this? See..
obj1:=TMyObject.Create;
obj2:=TMyObject.Create;
Try
Obj1.DoSomething1;
Obj2.DoSomething2;
Finally
FreeAndNil(Obj1);
FreeAndNil(Obj2);
end;
In your
Marcos Douglas escreveu:
Better:
obj1 := nil;
obj2 := nil;
Try
obj1 := TMyObject.Create;
obj2 := TMyObject.Create;
obj1.DoSomething1;
obj2.DoSomething2;
finally
obj1.Free;
obj2.Free;
end;
The objectcs are protected. But is boring... :)
Everybody codify like that, afraid if
On Tue, Jul 6, 2010 at 10:31 AM, Marcos Douglas m...@delfire.net wrote:
Better:
obj1 := nil;
obj2 := nil;
Try
obj1 := TMyObject.Create;
obj2 := TMyObject.Create;
obj1.DoSomething1;
obj2.DoSomething2;
finally
obj1.Free;
obj2.Free;
end;
The objectcs are protected. But is
In our previous episode, Andrew Brunner said:
obj1 := nil;
obj2 := nil;
Try
?obj1 := TMyObject.Create;
?obj2 := TMyObject.Create;
?obj1.DoSomething1;
?obj2.DoSomething2;
finally
?obj1.Free;
?obj2.Free;
end;
The objectcs are protected. But is boring... :)
Everybody
On Tue, Jul 6, 2010 at 11:39 AM, Marco van de Voort mar...@stack.nl wrote:
In our previous episode, Andrew Brunner said:
obj1 := nil;
obj2 := nil;
Try
?obj1 := TMyObject.Create;
?obj2 := TMyObject.Create;
?obj1.DoSomething1;
?obj2.DoSomething2;
finally
?obj1.Free;
On 06 Jul 2010, at 18:42, Andrew Brunner wrote:
Double Nope. You cannot access methods of a nil object.
You can, as long as such methods are not virtual (and free is not a virtual
method).
Nil.Free
will in-it-and-of-it cause a read access violation.
This is what free does:
if
On Tue, Jul 6, 2010 at 2:04 PM, Reimar Grabowski reimg...@web.de wrote:
On Tue, 6 Jul 2010 12:05:36 -0300
Marcos Douglas m...@delfire.net wrote:
We talk about just *functions* or we talk about *methods* too?
It is meant for 'method functions', too. But I don't follow that rule
strictly and
On 06 Jul 2010, at 19:51, Marcos Douglas wrote:
Can an exception happen in Free method?
It can happen in Destroy, which is called by Free.
Jonas
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On Tue, Jul 6, 2010 at 2:55 PM, Jonas Maebe jonas.ma...@elis.ugent.be wrote:
On 06 Jul 2010, at 19:51, Marcos Douglas wrote:
Can an exception happen in Free method?
It can happen in Destroy, which is called by Free.
And do not have medicine for that, right?
Marcos Douglas
On 06 Jul 2010, at 20:06, Marcos Douglas wrote:
On Tue, Jul 6, 2010 at 2:55 PM, Jonas Maebe jonas.ma...@elis.ugent.be wrote:
On 06 Jul 2010, at 19:51, Marcos Douglas wrote:
Can an exception happen in Free method?
It can happen in Destroy, which is called by Free.
And do not have
On Tue, 6 Jul 2010 14:54:29 -0300
Marcos Douglas m...@delfire.net wrote:
Like obj1.CreateObj() ? =)
Sounds a little generic for my liking, but at least you can guess that there is
something more going on than just returning a value, so, yes. :)
I'd rather use something like obj2 :=
On Tue, Jul 6, 2010 at 4:09 PM, Reimar Grabowski reimg...@web.de wrote:
On Tue, 6 Jul 2010 14:54:29 -0300
Marcos Douglas m...@delfire.net wrote:
Like obj1.CreateObj() ? =)
Sounds a little generic for my liking, but at least you can guess that
there is something more going on than just
On 6 July 2010 18:42, Andrew Brunner andrew.t.brun...@gmail.com wrote:
Nope. If Obj2 failed to create you will have a problem with Obj2.Free.
Nope. That's why it is free and not destroy.
Double Nope. You cannot access methods of a nil object. Nil.Free
will in-it-and-of-it cause a read
On 6 July 2010 19:51, Marcos Douglas m...@delfire.net wrote:
That's the problematic one I think.
Can an exception happen in Free method?! :-O
Yes! I often have to debug those in our complex business objects.
--
Regards,
- Graeme -
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fpGUI -
On Tue, Jul 6, 2010 at 5:04 PM, Graeme Geldenhuys
graemeg.li...@gmail.com wrote:
I meant is as in it is safe to call MyObj.Free even if MyObj = nil. I
answered based on the explicit question.
But yes, in your example where MyObj was an instance, the code in the
destructor could still trip
Andrew Brunner wrote:
It most certainly is not safe. LOL. Free calls destroy.. Destroy
may contain other frees and routines... You cannot guarantee that free
will even return.
the point was to call .Free on an object that might not have been
initialized, not what Free ( or destroy, for the
On 7 July 2010 00:04, Andrew Brunner wrote:
You got that right. Which is my point exactly. If free blows out w/o
a nested exception handle to catch it... The entire object goes into
limbo and will never be free and thus cause a memory leak.
Even with a try..except, if you call MyObj.Free
On Tue, Jul 6, 2010 at 5:09 PM, Graeme Geldenhuys
graemeg.li...@gmail.com wrote:
Even with a try..except, if you call MyObj.Free and it causes an
exception, you are screwed either way and it will always cause a
memory leak. Best is no notify the user some how, or crash out of the
program, or
On 7 July 2010 00:09, Andrew Brunner wrote:
Whew, Ok. Years back Delphi (the experience I'm drawing on)
Object.Free could not be done. Now that I know FPC does the check for
nil I probably won't be using FreeAndNil anymore. But this raises a
large concern for me. That is the EXTRA if
On Tue, 6 Jul 2010 17:14:38 -0300
Marcos Douglas m...@delfire.net wrote:
Well... I think use a name as CreateSpecialTMyObjectInstance() is very
especific... but, as you said, in the end it is all about personal
style.
Perhaps I have not made myself clear.
example (makes not much sense; just to
On Tue, Jul 6, 2010 at 7:14 PM, Andrew Brunner
andrew.t.brun...@gmail.com wrote:
On Tue, Jul 6, 2010 at 5:09 PM, Graeme Geldenhuys
graemeg.li...@gmail.com wrote:
Even with a try..except, if you call MyObj.Free and it causes an
exception, you are screwed either way and it will always cause a
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