Hi, Depends on the platform See number 1 What objects ? How are you creating them ? What's their lifetime ? In any case, KDAB's GammaRay is a very interesting tool. Valgrind is another one.

@Chris-Kawa This is to ensure there's only one instance of it Ah, yes, I completely slept through this minor detail ... :$ Sure you could do something like this instead No thanks, I'll take your QPointer suggestion any day. The latter is ... well it's work-aroundishly ugly ... Sorry about that. Not at all, I agree with the "premature optimization is the root of all evil" stance I just didn't see the proximate cause for it here, that's all. ... hard to get wrong. This is what I always liked about the stack, as I'm lazy and don't like debugging bad code ... especially if it's mine ... ;)

@jpnurmi Thank's a lot! That's it :) Now everything works like a charm :) You saved my day!

@cheezus JavaScipt source doesn't leak now.but QML side still leaks.please .

AFAIK, you'll to write a bit of Objective-C++ in this case to send an event or a signal to your application to act on that situation. You can also make a feature request to get something in Qt for that (or if you write for your application, make a submission with it :))

@ForestPoem said: nArray thanks. nArray = arrayNum It's my mistake. The two are the same

Well it depends on what you mean if you say "utilization". From application point of view file cache is free memory. See here: http://www.logicmonitor.com/blog/2014/07/17/the-right-way-to-monitor-virtual-memory-on-linux/

Using setText will avoid useless delete/allocation of items.

Hi, i was experiencing the same strange thing... i was using Qt headers and non Qt headers, and placing before the Qt headers seemed to have solved the problem.

Hi and welcome to devnet, IIRC, there might something to be done. Have a look at qmalloc.cpp. But I don't remember the exact constraints. Hope it helps

Hello, Both inputs are highly appreciated. I understand better how, when and why should I choose pointers over refs. I'm still reading some stuff here and there on how to produce some good code. Memory management has always been a doozy matter in C++ and i just can't get this Stroustrup quote out of my head : "C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do it blows your whole leg off. ". Thanks again for replying so quickly, I will apply everything i've learned here on my work asap. Best regards.

Oooh, should I use i insted of 0 in this line screenshot = screen->grabWindow(0); ??

If your question was how to initialize QObject from child you do not need extra Parent variable, no extra deletes, just add it in constructor: Contact::Contact(int cat,QString fir,QString lst,QString ad,QString zp, QString ct,QString nm,QObject *parent) ::QObject( parent ) { .......... }

Hi, I think it's on way... My compilation has passed !!! I have juste some error with linking library, I have compiled in 64bits my personnal library. That remove some errors, but I have one that can't be recompile, (supplier lib) who can I include it ? You have an idea @Goddard ? Thx your reply.

@emppu How to prevent that a user opens the same window twice? Do I need a flag variable in C++ code or is it easily done in QML? This seems a common workflow (preference window, open/save dialog, etc). I don't want to disable the main window while About window is open. You can do it right itself in QML. Declare component as global property and then check for null before creating that component. property Component component ... MenuItem { ... onTriggered: { if(!component) { component = Qt.createComponent("About.qml"); var about = component.createObject(main); about.show(); } } } In my case main window didn't disable. Did you set any particular Qt::WindowFlags flag ? If I keep an instance of About window as an attribute of main ApplicationWindow, does it occupy the memory since the main window is loaded? If I have many different windows, this is really inefficient. What's the simplest solution? Anything instantiated will occupy memory. To delay that process you use the technique you mentioned or you can use Loader to load them dynamically.

Ok, thanks :).