After removing a form (let's say Form2) from the project's "Auto-Created
Forms",
to instantiate dynamically the form at runtime, is it better to write
(in the main
form unit) :

TForm2 *form2=new TForm2(this) ;
... etc
delete form2 ;

or

TForm2 *form2=new TForm2(NULL) ;
... etc
delete form2 ;

I thought it was better to give the form no Owner (NULL), until I read
a program where they tranmitted the Main Form as the owner.

Michel Corbin

news:3EB563FA.F79F5FF9@libertysurf.fr...

They are both the same, as far as the allocate itself goes.  The only
difference between them is that the first one assigns an Owner to the form,
whereas the second one doesn't.  The Owner is responsible for freeing the
object when the Owner itself is freed.  This is good practice, in case your
own code doesn't explicit 'delete' the object first for whatever reason, the
Owner will ensure the object still gets freed properly later on so the
memory isn't leaked.

Gambit

"Remy Lebeau (TeamB)" wrote :

Thanks, so I can always write :
TForm2 *form2=new TForm2(this) ;
// and later :
delete form2 ;

in fact I was afraid that doing so, the Owner could attempt to free
something
already freed by "delete form2 ;"

Michel Corbin

news:3EB65C9B.CAF5026C@libertysurf.fr...

Have a look in the help files for Release().

From what I can make out it seems to be the preferred method for freeing
memory associated with Forms.

form2->Release();

news:3EB65C9B.CAF5026C@libertysurf.fr...

Nope.  When an owned component is freed, whether automatically or
explicitially, it removes itself from its Owner's internal list so that the
Owner won't try to free it again later.

Gambit

Hi, Michael!

Always remember when you have to manually free something, to make sure
you use either a smart pointer or try/__finally to ensure the resource
is deleted, even if you experience an error.

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