Problem when dereferencing std::unique_ptr with QT (Segmentation fault) - c++

Question

(Sorry for my future mistakes, I am fr)
I am creating a program to control the pc with a phone in c++ ( https://github.com/titicplusplus/PCPhone )
The server part works good, so I would like to add graphics interfaces for user, I decided to use QT.
When I stop the program QT, I have segmentation fault, and that stops the server.
My function that run the graphic interface:
void start_g(int argc, char **argv)
{
QApplication app(argc,argv);
QFile File(":/stylesheet.qss");
File.open(QFile::ReadOnly);
QString StyleSheet = QLatin1String(File.readAll());
app.setStyleSheet(StyleSheet);
ui interface; //QWidget window
interface.start();
std::cout << "start gui" << std::endl;
interface.show();
app.exec(); //return 0
return;
}
I encapsulated the code in a function because I would like to run it in a thread, but for now during my tests, I don't do this.
Here is my class ui (user interface)
class ui : public QWidget
{
public:
ui();
void start();
void change_file();
void change_port();
void freset();
void fapply();
~ui(); //Here is the problem
private:
openf f_open; //to open the extension s file
std::unique_ptr<QFormLayout> formLayout;
std::unique_ptr<QGroupBox> settings;
std::unique_ptr<QVBoxLayout> main_layout;
std::unique_ptr<QGridLayout> grid;
std::vector< std::vector< std::unique_ptr<QPushButton> > > tab2d;
std::unique_ptr<QGroupBox> all_button;
std::unique_ptr<QSpinBox> port_l;
std::unique_ptr<QPushButton> button_f;
std::unique_ptr<QPushButton> apply;
std::unique_ptr<QPushButton> reset;
std::unique_ptr<QLabel> text_f;
};
and the important function
ui::ui() {}
void ui::start()
{
grid = std::make_unique<QGridLayout>( this );
/** Code that you don't need, I guess **/
std::cout << "setting part" << std::endl;
all_button = std::make_unique<QGroupBox>("Slide");
all_button->setLayout(grid.get());
port_l =std::make_unique<QSpinBox>(this);
port_l->setMaximum(65535);
port_l->setValue( config_json["port"].get<int>() );
button_f = std::make_unique<QPushButton>("Open Image" ,this);
text_f = std::make_unique<QLabel>(QString::fromStdString(fs::absolute(config_json["image"].get<std::string>())), this);
apply = std::make_unique<QPushButton>(" Apply " ,this);
reset = std::make_unique<QPushButton>("Reset" ,this);
//connect(button_f.get(), &QPushButton::clicked, this, &ui::change_file);
connect(port_l.get(), QOverload<int>::of(&QSpinBox::valueChanged), this, &ui::change_port);
connect(apply.get(), &QPushButton::clicked, this, &ui::fapply);
connect(reset.get(), &QPushButton::clicked, this, &ui::freset);
//auto fileName = QFileDialog::getOpenFileName(&window, "Open Image", "/home/$USER", ("Image Files (*.png *.jpg *.bmp)"));
formLayout = std::make_unique<QFormLayout>();
formLayout->addRow("The port", port_l.get());
formLayout->addRow(text_f.get(), button_f.get()); //////////The problem is here
//formLayout->addRow(apply.get(), reset.get());
settings = std::make_unique<QGroupBox>("Settings");
settings->setLayout(formLayout.get());
main_layout = std::make_unique<QVBoxLayout>(this);
main_layout->addWidget(all_button.get());
main_layout->addWidget(settings.get());
}
So I saw on google, the problem come with the pointers and they destroy, so I try this
ui::~ui()
{
main_layout = nullptr;
settings = nullptr;
all_button = nullptr;
std::cout << "1u" << std::endl;
button_f = nullptr;
std::cout << "2u" << std::endl;
text_f = nullptr;
std::cout << "3u" << std::endl;
apply = nullptr;
std::cout << "4u" << std::endl;
reset = nullptr;
std::cout << "5u" << std::endl;
grid = nullptr;
std::cout << "bye bye" << std::endl;
}
The result is [ the errors are in french so I try to translate it ]:
1u
Segmentation fault (core dumped)
When I delete this line formLayout->addRow(text_f.get(), button_f.get());
There are no problems the deference of text_f and button_f, but with the next (apply and reset).
1u
2u
3u
Segmentation fault (core dumped)
On google, I saw a lot a time the people use the pointer and not the std::unique_ptr with qt, but I saw in general that people say "the smart pointer are better than the normal pointer.
Also, I try to replace button_f.get() to std::move(button_f).get() but that doesn't work.
For information, I am on Ubuntu 20.04, with g++-9.3 and qt5.
Thank you in advance for your answers !

Answer 1

Thanks G.M. and vahancho
I understand why I don't need to do std::unique_ptr .
When I learn C++ and pointer, there are rule : write one delete for every new, or better, use the smart pointer.
But with this two topics:
https://codereview.stackexchange.com/questions/43189/deleting-pointers-in-qt5/43201
Deleting Pointer to widget Qt C++
For the QT object, it's QT that deletes the pointers when the class is delete.
So I just need to need change all of my std::unique_ptr in raw pointer.