problem opening one instance of every Widget(form) and deleting it ...

[Proton Phoenix]

Hi ~~~
i have multi forms ... and mainwindow .. with a Menu inside it a lot of buttons .. every button connected with a special form
i want if i click to a button it opens the needed form only one time (one instance) .. and if i close it it release the memory ... if i open it once again it open ...
every form i want it to open just one instance ...
for example
this would open new instance everytime i clicked and clear memory without problem

activatesoft* actsoft = new activatesoft();
    actsoft->show();
    actsoft->setAttribute(Qt::WA_DeleteOnClose);

//////mainwindow.h

class MainWindow : public QMainWindow
{
    Q_OBJECT
    benefits* benefit=NULL;
// if i set this as private variable the software crashes if i open the form second time (after one close)
}

//////mainwindow.cpp

MainWindow::~MainWindow()
{
    delete ui;
//// i tried this too delete benefit but it doesn't work
    benefit->deleteLater();
}

and this :
 if (!benefit)
    benefit = new benefits();
    benefit->show();

would open just one instance but even if i delete it it doesn't release the used memory

is there any solution

[Christian Ehrlicher]

How did you check that deleteLater() (or a direct delete) does not work?

[Proton Phoenix]

@Christian-Ehrlicher

the same yes it doesn't work may be my problem was i deleting it on mainwindow destructor .. not benefit one ...
mainwindow is the parent
if i put the instance as private variable .. it release the memory once the window closes ... but if i open it once again the software crashes

[Christian Ehrlicher]

Please re-read your last post and think about it if anyone except you understands what you're trying to tell us.

[Proton Phoenix]

@Christian-Ehrlicher

i have multi forms ... and mainwindow .. with a Menu inside it a lot of buttons .. every button connected with a special form
i want if i click to a button it opens the needed form only one time (one instance) .. and if i close it it release the memory ... if i open it once again it open ...
every form i want it to open just one instance ...

[JonB]

@Proton-Phoenix
In a word: why don't you just have an instance (not a pointer to) of this widget/form in your main window? No need to new or delete . One instance.. Sounds like just what you want?

[Christian Ehrlicher]

Then don't delete it on close and re-open this instance later on - basic c++ stuff, nothing Qt-specific.

[Proton Phoenix]

Thank you so much for helping i will try that
i still new on c++
just trying bruce lee methods to learn things as it can be when i hit a barrier .. i search for solution ... until i reach most of its database

Thank you all of you

[Proton Phoenix]

@JonB it works bro thank you
problem fixed
when i tried this before it doesn't open the window at all ... just flashing but now i understand why it's working
Thank you <3