Qt 6.2 pixmap(Qt::ReturnByValueConstant) syntax

[Rory_1]

I need some syntax help. I'm updating deprecated code in Qt 5.15 for QLabel::pixmap(). I have a QLabel *progress. My current code:

int w = progress->pixmap()->width();  // works in Qt 5.15

I am trying to change to the new QPixmap::pixmap(Qt::ReturnByValueConstant) const
I have tried:

int w = progress->pixmap(Qt::ReturnByValueConstant)->width();  // does not work

I am getting an error: expected '(' for function-style cast or type construction. The Qt namespace documentation says Qt::ReturnByValueConstant is a dummy enum.

So I tried:

int w = progress->pixmap(Qt::ReturnByValueConstant())->width();  // appears to work

Is this the correct syntax?

[Christian Ehrlicher]

@Rory_1 said in Qt 6.2 pixmap(Qt::ReturnByValueConstant) syntax:

Qt::ReturnByValueConstant

pixmap(Qt::ReturnByValueConstant) returns (as the enum properly says) an object, not a pointer to an object. So you should use . instead ->.

[Rory_1]

@Christian-Ehrlicher Hits side of head. Of course. Thank you very much.

[JKSH]

@Rory_1 And after you've updated all your deprecated code, disable all deprecated functions (for example, by setting DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x051500 in your .pro file). Once you've done this, you can clean up your code by getting rid of the dummy enum:

// int w = progress->pixmap()->width(); // Original code, deprecated
// int w = progress->pixmap(Qt::ReturnByValueConstant).width(); // Transition code
int w = progress->pixmap().width(); // Final code

[Rory_1]

@JKSH Thanks!