[SOLVED] CreateForm Error

[Windsurfer]

I  am using lazarus 1.2RC1 on Windows 8.0.

I recently installed the free version of Avast (virus checker). Since then all of my code that creates a new form fails after closing the new form and then trying to create it again.

I have now shutdown Avast, but the error remains.

The error message is:
--------------------
Project project1 raised exception class 'External: SIGSEGV'.

At address 403D34
--------------------

The attachment is a simple project that always fails when form2 is opened a second time.

Could someone please check it on R1.2RC1?

[engkin]

Code: [Select]

..
    if Form2 = nil then Application.CreateForm(TForm2, Form2);
    Form2.Show;
..


Code: [Select]

Procedure Tform2.Formclose(Sender: TObject; Var CloseAction: TCloseAction);
  Begin
    CloseAction := caFree;
  End;

The second time you call it, Form2 is not nil and it points at the destroyed form. It should give you a nice SIGSEGV

You need to set Form2 tol nil when you destroy it.

[Windsurfer]

Thanks engkin,

I added Form2 := nil;

after

CloseAction := caFree;

and it worked. I assume that my previous testing was incomplete.

My reason for creating forms dynamically is to reduce memory footprint. I used to program with if form2 <> nil then etc.. and avoided the problem without knowing it.