Can you explain me this code?

[thippu]

1)I have code like this

void MainWindow::openInifile()
{
     QSettings settings(new QSettings("filename path and filename",QSettings::IniFormat));
     setSettingsObject(settings);//I think it is passing its content that is a reference, am I right?
}

2. In the function, they are creating the QSettings object on the stack memory but passing the heap memory of the same type reference. will that stack object get deleted when it goes out of scope? and let me know the reason and what is the advantage of it.

[jsulm]

@thippu said in Can you explain me this code?:

setSettingsObject

Can you show its signature?

"I think it is passing its content that is a reference, am I right?" - can't you simply check its declaration to answer this question?

[thippu]

@jsulm said in Can you explain me this code?:

Can you show its signature?

void setSettingsObject(const QSettings &settings);

[jsulm]

@thippu In this case you need to check what setSettingsObject does to know whether it is a bug or not. Can you show its content?
Actually, as long as setSettingsObject does not store a pointer to settings there will not be any error. Most probably they just assign it to an instance variable, in which case it is copied (assignment/copy operator).

[VRonin]

@thippu said in Can you explain me this code?:

QSettings settings(new QSettings("filename path and filename",QSettings::IniFormat));

yeah, this is really poor. Since QSettings is a QObject it compiles as it uses this constructor but the object allocated in the heap is unused and leaked.
Whoever wrote that code should undergo dire punishment

[jsulm]

@VRonin Oh, somehow I missed that "new" :-)

[thippu]

@jsulm said in Can you explain me this code?:

In this case you need to check what setSettingsObject does to know whether it is a bug or not. Can you show its content?

It was from the example "Settings editor", I'm studying the mechanism of it.

[jsulm]

@thippu See what @VRonin wrote. I didn't notice the "new QSettings", need to read more carefully :-)

[jsulm]

@thippu said in Can you explain me this code?:

example "Settings editor"

Oh, if this is from official Qt example than you should file a bug as this is a bad example then.

[thippu]

@jsulm said in Can you explain me this code?:

Oh, somehow I missed that "new" :-)

Really, you are the author?. :-)

[jsulm]

@thippu No, I'm not else @VRonin would punish me :-)
I mean I did not notice it then I read your first post in this thread. I think I didn't notice it because I read it while you were stil changing it. It was first

QSettings settings;

[J.Hilk]

@VRonin said in Can you explain me this code?:

Whoever wrote that code should undergo dire punishment

Well, should be possible. It's been written here

http://doc.qt.io/qt-5/qtwidgets-tools-settingseditor-mainwindow-cpp.html

should be in the docu change log right :)

[thippu]

@jsulm oh, yeah true I did edit once.

[VRonin]

@thippu said in Can you explain me this code?:

It was from the example "Settings editor", I'm studying the mechanism of it.

The example is correct: typedef QSharedPointer<QSettings> SettingsPtr; and then

SettingsPtr settings(new QSettings(locationDialog->format(),
                                       locationDialog->scope(),
                                       locationDialog->organization(),
                                       locationDialog->application()));

or SettingsPtr settings(new QSettings(fileName, QSettings::IniFormat));

The problem is you took the liberty of replacing a shared pointer with a stack object

[thippu]

@VRonin you are right, sorry, I thought that time It would not matter.