Qt 5.0 Released

sfcrazy writes "The Qt project and Digia, the company behind Qt framework, have released the most awaited C++ framework for developers, Qt 5.0. The company claims it's one of the best releases to date and has invested a significant amount of time behind this release. It's an overhaul of the Qt 4.x series and makes Qt fit for the future." Update: 12/19 17:46 GMT by U L : Major new features include an overhauled graphics layer, full integration of Qt Quick for creating flexible interfaces using Javascript, and increased modularization including the first steps toward de-emphasizing QtWidgets by separating them into their own module.

Comments

Hmm

[LizardKing]

The company claims that it's one of the best releases till date

Well, you would rather hope so.

A good example of a bad summary

[i kan reed]

This is like the millionth time that we've had a headline that is "Open source project whose name does not imply function releases new version"
And a summary that is "The version number, which we're happy to tell you, was highly anticipated, but forget any discussion of what the project is".

I know we like open source here, but if the project is anything other than linux, a major distro, or a major programming language, this is awful editting, that repeats over and over. Not even mentioning any new features is inexcusable.

For everyone else: Qt is a library/framework for developing GUI applications.

Re:A good example of a bad summary

[mark-t]

...or, they could just follow the link and see for themselves.

Oh right, this is slashdot.

But it's not even like you have to read anything. It's a video demonstration.

Re:A good example of a bad summary

[Anonymous Coward]

... hence thousands of non-programmers continue to talk about how superior it is to GTK+

Having done a small amount of Qt programming, it's also one of the most pleasant APIs I've worked with, both in its C++ form and in PyQt.

Re:A good example of a bad summary

[Anonymous Coward]

It's not just for GUI applications. The library has a bunch of different features that help make cross platform applications such as networking. (I use it for other things now since I'm used to all the templates and features that come with it.) But yeah, mostly used for GUI applications.

Re:A good example of a bad summary

[TigerTime]

Yep. From the summary, I have no idea what Qt does. What is new in this version. Or how it affects me.

All the summary told me was that it's a new version of a C++ project. And it's supposed to be better than the last version.

Re:A good example of a bad summary

[jeffmeden]

If you don't know exactly what QT is/does since the first time you compiled it in order to run kvirc back in 1998... Then I don't know what you are even doing here.

Re:A good example of a bad summary

[matunos]

If you didn't already know what Qt was, then you're probably not going to be particularly interested that version 5.0 is out.

Re:A good example of a bad summary

[knuthin]

this is awful editting

That doesn't sound right coming from a person spelling "editing" wrong.

Re:A good example of a bad summary

[Johann Lau]

That seems like totally valid criticism to me. So you're saying Qt is equal or inferior in all respects, and uses more resources? You should blog about this, because no amount of googling turns up remotely similar results. As a matter of fact, people seem to be quite happy with Qt, and "shinyness" doesn't even get mentioned in those discussions. Or is shiny just code for "not as fugly" .. ? Please elaborate.

Re:A good example of a bad summary

[fredprado]

There is no comparison between QT and GTK+. QT is by far superior in about everything. Only hipsters like you think otherwise.

Re:A good example of a bad summary

[Anonymous Coward]

I can vouch for this as someone whose primary reason for liking gtk+ was that it was in C:

QT is definitely better architected, and especially in newer iterations QT is generally much faster with the default widgets than GTK+ 3.

Additionally they've got the excellent qt-creator, of which I have yet to find a decent gtk+ equivalent (adjunta(sp?) is ok, but it's got a lot of gnome interdependancies for basic functionality, whereas QT rolls all the important stuff into a single uniform library base.)

Additionally QT is MUCH better at being cross-platform than gtk+ in it's default form.

Re:A good example of a bad summary

[Anonymous Coward]

You obviously never programmed with QT then. QT API is generally pleasant to work with in that it's well documented, consistent, and not unnecessarily complex with a decent amount of examples.

QT is a larger framework because it does quite a bit more then GTK+ and others. In a Linux environment, that ram usage is shared so you can end up using much less ram in the end with multiple programs running on the same large library. This unfortunately is less of an advantage in Windows (where you see much less GTK+ or QT) but QT is split into several libraries meaning that you don't have to attach the entire framework to your code.

Realistically, QT isn't that large of a library for modern applications. It's definitely not the smallest but ease of programming is something to be said.

Is GTK+ bad? Never said that, but neither is QT. Simply pick the best library that works for you. For me, QT is definitely one of my top choices (though not always) after working with several frameworks.

Re:A good example of a bad summary

[AvitarX]

Even worse, I don't know what "C++" or "project mean"!

Re:A good example of a bad summary

[Anonymous Coward]

Try to make tabs that you can drag and drop as docks with the central widget of QMainWindow. Better yet, look up QThreads and the QObject supering solution...
Tell me how you like that "pleasant APIs" then...

I agree it's probably the best GUI kit for simple or obvious stuff. But it's lacks are hardwired in the core widgets so unless you are prepared to rewrite QMainWindow - not just super it mind you - you're fucked. This is especially true when it comes to the language bindings like PyQt.

Considering the cluster fuck GTK has become, I'm betting on EFL myself and have started (this week) to learn it. It's still quite young but it's already clear to me that it addresses all those weakness I've mentioned and many more right from the start. I just hope it will become more mainstream now that E17 is pushing stable.

Re:A good example of a bad summary

[PNutts]

If you didn't already know what Qt was, then you're probably not going to be particularly interested that version 5.0 is out.

Of course I know what QuickTime is. I occasionally uninstall it so I can reinstall it and get the offer to upgrade to Pro so I can see the chick on the surfboard.

Re:A good example of a bad summary

[lister king of smeg]

It is not is such a unreasonable thing as to assume basic knowledge of the field. This is a site predominantly amid at compsci people and largely open source/*nix people at that. Knowing what qt is or the ability to find out on your own what qt is, is not unreasonable here. If you think they should have give you a definition of qt then why not ask for a definition for C++ as well as that would be just as nonsensical in this context.

Re:A good example of a bad summary

[Anonymous Coward]

Please elaborate.

Trolls don't elaborate. They troll.

Re:A good example of a bad summary

[bluefoxlucid]

RAM usage doesn't come from big libraries. It comes from massive data sets being used to instantiate a whole bunch of shit. Libraries, even big ones, are small.

Re:A good example of a bad summary

[Just Brew It!]

Agreed. I've never developed anything using Qt, but have a pretty good idea of what it is. Even if I'd never heard of it before, a couple of mouse clicks and 3 keystrokes (assuming I've got Google or Wikipedia bookmarked) would've yielded an answer in seconds. Given this, and the fact that most people on /. probably already have at least a vague notion of what Qt does, I don't think it is necessary to explain it every time it comes up.

Re:A good example of a bad summary

[Johann Lau]

I know that... I was essentially asking to be trolled some more :D

Re:A good example of a bad summary

[Anonymous Coward]

While what you said is true for static linked libraries, dynamically linked ones load the entire library into memory. Both GTK+ and QT are LGPL meaning being static linked severely limits your license choice of your application (A biggie for Windows which tends to be more commercial or freeware) and loses the benefits of Linux shared libraries (Static linked generally only used for standalone Linux packages that don't rely on a repository but user downloaded installation). Basically, many application will tend to be dynamically linked either due to license issue or reduced ram usage (when used with multiple programs).

The type of ram usage depends entirely on the application where the library can make up the majority of ram usage or the minority when dynamically linked. You really can't generalize though it's more simple programs that tend to be the former.

Your remark though of "Well, it's superior in its ability to increase program load times and consume a lot more RAM, I guess" which is the main part I have issue with can be inferred as "QT has no merits beyond extra ram usage over GTK+." That is false and ignores that people prefer different things. There are plenty of reasons why one would choose QT of GTK+ (the opposite is also true) like it's larger range of supported devices, API like Qt Quick, and probably other things like user preferences of slots/signals over events/callbacks.

Basically, QT is perfectly fine. It's main role is similar to GTK+ but so what? So is many libraries that all do the same things. Everyone has their personal preferences. If alot of people prefer QT, well, obviously there some merit to it but I'm sure many people like you will also prefer GTK+. Discussing about implementations leads to improvements or at least knowledge, outright dismissal of implementations can lead to ignorance.

Re:A good example of a bad summary

[Anonymous Coward]

Because Outlook, Excel, Access and Powerpoint are just totally evocative of email, spreadsheets, databases and presentations.

Also, do you not have that function in your browser where you highlight a word, right click it and select 'Search for X with Google/Bing/Yahoo/whatever' from the context menu? What kind of person just stares at a word they don't understand and then goes to the trouble of complaining that whoever wrote the word didn't tell them what it means? Put just the tiniest bit of effort in ...

CAPTCHA: Moaned. How appropriate

Re:A good example of a bad summary

[i kan reed]

I don't ask that they name their products to my whims, just that the idiots who submit the articles acknowledge that not everyone has heard of their stupid favorite library.

Re:A good example of a bad summary

[Anonymous Coward]

Try to make tabs that you can drag and drop as docks with the central widget of QMainWindow.

What?
No user will ever want that. Ever.

Re:A good example of a bad summary

[ChunderDownunder]

Speak for yourself. Some of us have multiple monitor setups, e.g. 1 in landscape, 1 in portrait. The ability to dynamically attach/detach tabs as separate windows is very handy. IDEs and web browsers make use of this feature.

Re:A good example of a bad summary

[smaddox]

I haven't tried to code something like this, but you should check out how Veusz does it, because it works perfectly.

Re:A good example of a bad summary

[Grishnakh]

As someone who's been on Slashdot since the 90s, I think you're tilting at windmills. When was the last time you saw a really good summary on Slashdot? Shitty summaries are the norm here, and they're frequently downright misleading and contradicted by the articles linked. There is NO editorial control here, just sensationalism.

Qt Qt Qt

[Anonymous Coward]

The Qt project and the company behind Qt says the latest version of Qt, which is an overhaul of the previous Qt version, is one of the very bestest releases of Qt that Qt has ever released. Qt!

Re:Qt Qt Qt

[NotBorg]

That's true of any product release by any company. The releaser is always going to make the claim that it's better than before. It's up to you, the consumer, to look at the product and make a decision. If you want to make an informed decision you'll probably need to look at both what its promoters and its detractors have to say about it. This article is obviously about the promotion side of the product. You may find some detractors in the comments but so far they're doing a piss poor job. You'll have to try Google.

You should probably not click on articles that are obviously (from the subject line even) intended to promote a new version. They're going to upset you because they are by nature somewhat one sided. For the rest of us, that's not a major point of contention because we know who's point of view it's from and that we'll have to do some more looking if we want to be wholly informed.

Now sit down and shut up. People will think you're more intelligent that way.

How about beefing up the summary a little ?

[Anonymous Coward]

Especially considering how irrelevant point releases are this days.

Has it grown to encompass the entire OS yet?

[Anonymous Coward]

Looks to be on the way to that, instead of just keeping a good clean GUI system. So, when is full QT OS coming out?

Re:Has it grown to encompass the entire OS yet?

[gmuslera]

You build things over it, like desktops (like KDE) or mobile (like the upcoming Sailfish) environments.

I use it so it's relevant to me.

[Anonymous Coward]

It's mature and has all the bells and whistles. Only other alternative is WxWidgets...

What else did you have in mind ?

Re:I use it so it's relevant to me.

[Anonymous Coward]

He probably means that because the brain damage management at Nokia couldn't get it going on a phone that it's doomed. Android and Apple won and if you buy into the "Desktop is Dead" idiocy then you think that mobile is the only target that matters. We won't tell the fuck head that 9 out of 10 times those "Desktop is Dead" articles are viewed from a desktop. It's confusing to them. No those are real numbers. Go look at all the sites you use to decide who's winning the browser war. They may disagree on which one is the absolute victor but they all agree that mobile browsers only account for about 10% of the total market. (Hint people are buying mobile phones because they are mobile phones more than because they come with a browser that will drive your data plan into ob$cenity. Almost no one but the hard core geek uses their mobile browser as much as the voice or texting services they purchased the phone for in the first place.)

Now if you don't buy into the hoopla and realize that the desktop isn't dieing then Qt is relevant, useful, alive and kicking. It takes more than Nokia shooting itself in the foot with Microsoft's gun to kill Qt.

Re:I use it so it's relevant to me.

[marcosdumay]

Almost no one but the hard core geek uses their mobile browser as much as the voice or texting services they purchased the phone for in the first place.

It's email (I'm resisting the temptation to finish that setence with "stupid", because you really doesn't deserve that label).

People use smartphones for email and things similar to it, like twiter and facebook updates. Not for the web, not for complex work, but for communication.

I used to think it was just me, but then, all the studies I've seen recently about how people read email point to that.

Re:I use it so it's relevant to me.

[Anonymous Coward]

Reading an article on the Internet is hardly "complex work." So how is it again that all the "desktop is dead" articles are being read on desktop computers? The point is that phones aren't replacing PCs the way that the popular brain damage says they are.

Re:I use it so it's relevant to me.

[Anonymous Coward]

There are definitely alternatives other than Qt and wxWidgets, but they're much smaller in scope and more specialized.

I work on phoenix, which is a wrapper around Win32+GTK+Qt, and eventually Cocoa. The idea being that you target whatever toolkit is native with the same code. Saves you 5-10MB worth of DLLs that you'd have to distribute with Win32/Qt, for instance. This approach has the incredibly major downside that your feature set is limited to the least common denominator of every platform, so you are limited to the most barebone UI components. Great for small apps, though.

Re:I use it so it's relevant to me.

[TemporalBeing]

It's mature and has all the bells and whistles. Only other alternative is WxWidgets...

What else did you have in mind ?

Here's the basic group that Qt belongs as part of:

• Qt
• Gtk
• WxWidgets (WxWindows)
• SDL

WxWidgets is public domain; and was the first (AFAIK) to do both Signals/Slots and Message Maps for inter-object comms.

Gtk was originally just MessageMaps, and now also does Signals/Slots; but it also tends to be heavily GNOME centric and rather largely ignored by GNOME in maintaining it - it moves along, but at a snails pace because they're not really paying attention to it (to my understanding from talking to someone in the GNOME community).

SDL isn't quite as feature complete as any of the others, but can get the job done.

Qt is really the only first class library in that group, and now reaches even more platforms than ever before. And with Qt embedded, it runs in many devices that you may never have thought of as having run Qt (Microwaves, TVs, Refrigerators, etc.). Qt really is to multi-platform development what Linux is to processors in that respect.

So in the sense that nothing else is really as feature complete and professional as Qt - yes, it's in its own category. But in reality there are several other major competitors - and all from the FLOSS community at that.

Re:I use it so it's relevant to me.

[Psychotria]

Small correction: wxWidgets isn't public domain. It's licensed under the wxWindows Licence which, as their page states, is like the LGPL but with a few differences.

Re:I use it so it's relevant to me.

[byuu]

SDL isn't quite as feature complete as any of the others, but can get the job done.

That's ... a bit of an understatement. SDL is a frame buffer, audio buffer, and input poller. For writing GUIs, it's about as feature-complete as QPainter. Sure, you can write your own GUI widget library on top of it, but that won't be pleasant for you or your users.

SDL is more suited for abstracting the platform video/audio/input APIs, and can be used nicely in conjunction with Qt, GTK+, etc.

Re:I use it so it's relevant to me.

[lengau]

Most people don't know what Qt is, though. They don't realise how much of the software they use uses it.

Re:I use it so it's relevant to me.

[TemporalBeing]

Small correction: wxWidgets isn't public domain. It's licensed under the wxWindows Licence which, as their page states, is like the LGPL but with a few differences.

Interesting. I hadn't looked at in in a few years (2004,2005). So they've changed their license since it use to be public domain. I was surprised at the time, but oh well. Good to see them using a nicer license though.

Tablet support?

[Anonymous Coward]

Last I heard they pulled Wacom tablet support. (QTabletEvent is still there, but never gets generated) Assuming this is still the case, this makes it a non-starter for a bunch of Qt Apps -- off the top of my head; Mari, Maya, and Mudbox among others.

Re:Tablet support?

[Unknown Lamer]

The standard xinput mechanisms have full tablet support now. You can even use use cheap knockoff tablets now thanks to digimend (I got one from monoprice and it's pretty great for messing around with handwriting recognition and I've discovered that image editing with a trackball + tablet is great). Unfortunately all tablets are kind of broken except in the latest release of X.org because of a bug with coordinate transformations (basically, the pointer jumps if you make pressure changes without moving because the code transforms the already transformed coordinates... it also left touchscreens pretty broken; the guy that fixed it caused something like a dozen ubuntu on nexus 7 bugs to be closed!).

Re:Tablet support?

[ameline]

You're being a little Linux biased there -- I think the OP was referring to tablet support on windows. And I believe that it is broken in Qt 5 on windows. (I'd be happy to be wrong on this.)

Lies.

[Anonymous Coward]

I work at QT, and have serious doubts that we could release a programming framework like this.

Re:Lies.

[Anonymous Coward]

QT isn't the company...troll.

C++ Standards

[joelholdsworth]

Did they make any moves towards using standard C++ features rather than the MOC ugliness? What with Boost::Signals, sigcxx and C++11, I see no reason why they have to bastardise the language to provide signals.

Re:C++ Standards

[joelholdsworth]

RTFA: They have made some good progress on this - but I can't tell if MOC is dead yet.

Re:C++ Standards

[Desler]

They aren't eliminating MOC. For one thing, they support a number of compilers that don't have and probably never will have full C++11 support.

Re:C++ Standards

[Anonymous Coward]

Then you don't understand what Qt has to offer. The signals and slots in Qt are awesome.

I for one welcome my MOC overload.

Re:C++ Standards

[N3Roaster]

Yes and no. The signals and slots mechanism is still there and it's still using moc, but there's a new connection syntax available that's a lot more C++ like, allows C++11 lambdas in place of slots, and offers compile-time checking of connections that previously would just fail at run time. Won't please the purists, but it's a step in the right direction.

Re:C++ Standards

[Anonymous Coward]

How are the degenerated boost and sigcxx reimplementation of Qt signals and slots system any more standard than the original? They even use preprocessors now like Qt does.

Re:C++ Standards

[Anonymous Coward]

Moc provides nice introspection features not available in normal C++. Why remove that? They are needed to integrate QML (declarative language for UI design) with C++.

You can use template-based signals and slots in Qt5 and even connect signals to lambdas.

Re:C++ Standards

[stenvar]

You don't need C++11 to replace MOC. MOC was obsoleted by C++ features many years ago.

Re:C++ Standards

[Noughmad]

Yes, they did. See the wiki page.

Re:C++ Standards

[loufoque]

Let me add that In this particular instance, many is 15 years.

Re:C++ Standards

[Anonymous Coward]

Wait, C++ is already horribly ugly all by itself.

Also I love the rationale for MOC, basically it's "we already have 11 layers of crap, so why not a 12th".

Re:C++ Standards

[Anonymous Coward]

No, it wasn't. Read e.g. http://www.macieira.org/blog/2011/09/the-future-of-moc/ , and http://doc.qt.digia.com/qt/templates.html.

Re:C++ Standards

[Urkki]

Let me add that In this particular instance, many is 15 years.

How do you call a C++ method by it's name from QML or javascript or C++ plugin without some kind of pre-prosessing step which actually stores the method names and argument types somehow to make invocation possible?

Re:C++ Standards

[loufoque]

dlsym(h, "my_method")
There is no need to store it, it's already in the symbol table.

If you do want to store it, there is no need to use an external preprocessor anyway.

Re:C++ Standards

[TemporalBeing]

dlsym(h, "my_method") There is no need to store it, it's already in the symbol table.

If you do want to store it, there is no need to use an external preprocessor anyway.

That works for functions, but not Class Methods that require an instance of the class. And, even more so, how do you do it in a multi-platform environment in a uniform way? (http://en.wikipedia.org/wiki/Dynamic_loading). Windows doesn't use dlopen/dlsym/dlclose but has its own Win32 functions to do something similar. You're also relying on RTTI; and not every compiler or environment supported by Qt supports RTTI. (RTTI also has its own run-time overhead which is bad in embedded environments like what Qt supports.)

Re:C++ Standards

[loufoque]

It works for any symbol, regardless of its type.
This has nothing to do with RTTI.

The API for plug-ins is platform-specific since there is no standard interface for C++ plug-ins.

Re:C++ Standards

[Anonymous Coward]

And if you strip your binary? Then you need to maintain a list of symbols to keep. Or you can use MOC which makes your build system easier & provides a whole slew of features beyond signal/slot (e.g. you can easily use QObject's within Javascript). Also, the syntax for MOC signal/slots is way way cleaner than the template approach typically used. While slightly less type-safe (i.e. runtime checking instead of compile-time), it's actually easier to write.

Re:C++ Standards

[Anonymous Coward]

Have you seen "C++" code generated by Visual Studio 200x? They add about 20 keywords and the code is full of ^ (garbage collected references AFAIR).

If you call MOC (which is just a pre-processing step that generates regular C++) ugly, you probably still use text prompt and console output as the UI for your apps.

Re:C++ Standards

[TemporalBeing]

It works for any symbol, regardless of its type. This has nothing to do with RTTI.

The API for plug-ins is platform-specific since there is no standard interface for C++ plug-ins.

Yes, you could use dlsym() when building the table MOC builds for the connector calls. That's it. That's also a very very small part of what MOC does. That could be done as part of the object constructor...except now you need to store both static compile-time information (the functions you want to add) and dynamic run-time information instead of just the static compile time stuff that MOC generates (in the moc_*.cpp files).

RTTI does a good bit of the rest of what MOC does. In neither case are they both supported by all platform+compiler combinations that Qt supports.

Qt5 now allows C++11 lambas in signal/slots; but only if you enable C++11 functionality when you build it - they still support compilers that don't support C++11 lambas.

Re:C++ Standards

[shutdown -p now]

It works for any symbol, regardless of its type.

You're still missing the point. How exactly, given a QObject*, can you ask it to give you some wrapper encapsulating a method named "foo"? Even if you're willing to do C++ name mangling yourself in a platform-specific way, you still need to know the actual type of the object to which you have the pointer, meaning that you need RTTI.

Re:C++ Standards

[shutdown -p now]

Can you explain what Qt slots/signals give you (apart from the need to do extra preprocessing) that Boost.Signal does not?

Re:C++ Standards

[loufoque]

I simply replied to the question "how do you call a C++ method by its name from a C++ plugin".
I don't see what this has to do with MOC.
There is no need to build any table either. There is no need to store anything, nor to use RTTI.

If you really wanted to generate tables of data (which again, I repeat, is not needed to do this), you still wouldn't need MOC anyway. You can just use macros and potentially templates to do that.

Re:C++ Standards

[loufoque]

Calling a member function through a pointer to base bound to a derived object works fine assuming the function is virtual.

Re:C++ Standards

[EvanED]

I simply replied to the question "how do you call a C++ method by its name from a C++ plugin".

You replied with an answer that works in some, but not all, cases -- even on the platforms on which it works at all.

Re:C++ Standards

[loufoque]

It does work in all cases.

Re:C++ Standards

[Unknown Lamer]

The problem is that the moc implements something more like the Common Lisp Object System's metaobject protocol for C++; resolving symbols at runtime is a tiny portion of what it does. dlsym and analogues on other platforms are also horrendously unsafe; a one way ticket to strange segfault bugs when you cast the result to the wrong type. And since C/C++ types are not first class, you can't even construct the casts at runtime! (Ok, maybe C++11 has some new foo_cast template, I'll admit my C++ is a bit rusty). You're also ignoring issues of syntax — unfortunately C++ doesn't provide the needed tools to construct embedded grammars in the language, and performing the tasks moc automates can be incredibly awkward otherwise.

Re:C++ Standards

[scorp1us]

Qt signals are modeled after boost signals. I can't say what other than syntax is different (Qt begin easier to read), but signals/slots are supported in all paradigms - PyQt/PySide, QtQuick (JavaScript) and in threads. I don't think Boost has support for JS and Python. Functionally though, they are the same.

http://www.richelbilderbeek.nl/CppFromQtSignalToBoostSignal.htm

Re:C++ Standards

[scorp1us]

First, it's not bastardized. C++11 is the bastardization, because it results in code fragmentation. That wonderful cross platform C++11 function you write can only be targeted by C++11 compilers. Meanwhile in Qt land everything keeps working on your legacy compiler. The fact that it uses compiler macros to accomplish cross-platform cross-compiler interoperability does not lend itself to "bastardization"

MOC is not ugly, though I would prefer a C# approach of not having to separate it into a H file, but this is more a C++ thing than a Qt thing. I love the QMeta* that allows me to have introsepction at run time (again x-platform) and I can even dynamically create classes. Can C++11 do that? (Well i guess it can if it's using Qt) But they are adding C++11 syntax if you are using a C++11 compiler and want to limit your portability.

Re:C++ Standards

[shutdown -p now]

Qt signals are modeled after boost signals.

That would be impossible, given that Qt signals appeared much earlier than Boost.Signals. Indeed, I don't think Boost itself existed at that time - the effort for that began in 1998, while the first release of Qt was in 1992 (and, if I remember correctly, it had signals/slots since inception).

can't say what other than syntax is different (Qt begin easier to read),

Boost.Signals is a pure C++ solution that relies on templates and does not need any kind of preprocessor. It works out of the box on vast majority of C++ compilers, including g++ and MSVC.

I don't think Boost has support for JS and Python.

Well, Boost is a C++ library. That said, you don't really need any special support for signals in JS or Python, because they already have functions as first-class types.

Re:C++ Standards

[Urkki]

dlsym(h, "my_method")
There is no need to store it, it's already in the symbol table.

If you do want to store it, there is no need to use an external preprocessor anyway.

Sorry, wrong answer. C++ method name symbols are mangled to include class name and parameters. Worse, this mangling is not standardized, it is compiler specific. In other words, that is not a method name, that is a C function name in the example you gave.

But it's even worse than just generating the symbol name. With virtual methods, you have to determine at runtime, what is the real class of the object pointer, because you need to call differently named method based on that. So, could be done with RTTI and compiler specific helper function to generate the mangled symbol name, but I don't remember anybody ever doing it...

Re:C++ Standards

[Urkki]

I don't think Boost has support for JS and Python.

Well, Boost is a C++ library. That said, you don't really need any special support for signals in JS or Python, because they already have functions as first-class types.

I think he meant, he doesn't think it's easy to create bindings for emitting Boost signals from javascript or Python, like you can do from javascript engine running in Qt app, or from PySide/PyQt application.

While this doesn't make sense for Boost alone, without context, it becomes relevant and even critical, if you have a library/framework using Boost as core signal/slot mechanism. If you do that, how easy is it to emit such signals from an interpreted language? Or, to put it other way, are Boost signals a realistic option at all, if you want to leave open the option to interface with a scripting language?

I don't know.

Re:C++ Standards

[shutdown -p now]

Well, Boost signals are just function objects. So long as whatever bridge you use to call C++ from a scripting language lets you invoke operator() on arbitrary stuff, it can emit a signal. I think Boost.Python would be able to do that, for example.

Re:C++ Standards

[loufoque]

It's a symbol name. Finding the symbol name of a particular member function is not a problem. You don't need the type either, the base type is enough.

Re:C++ Standards

[loufoque]

If you want to do duck typing, which is probably a bad idea, you'll indeed need to generate some runtime reflection data.

I don't see how generating that data is awkward using standard mechanisms.

Re:C++ Standards

[TemporalBeing]

It does work in all cases.

Only for functions, not for non-static class members; and (as I pointed out) not efficiently enough for how Qt manages signals/slots; not likely sufficiently enough for how Boost handles them either.

Re:C++ Standards

[loufoque]

It works fine for any symbol, including non-static class members or whatever else you've put in your binary. dlsym does not care about the type of the symbol or the calling convention to call it, that's up to you to handle.
Now then, what you can argue is that this isn't a nice programming interface. It isn't, it's just how the platform does dynamic linking.

Re:C++ Standards

[TemporalBeing]

Now then, what you can argue is that this isn't a nice programming interface. It isn't, it's just how the platform does dynamic linking.

It's also not portable. dlopen()/etc are not on Windows - which has its own unique interface for doing the same thing.

Re:C++ Standards

[scorp1us]

The point I was trying to make was that via the preprocessor approach, it becomes trivial for all these wrappers and interop between languages to happen. I've hacked MOC to produce alternate output as needed to automate some other tasks for me. I prefer having that step as it is useful, however C++ "purists" rather fragment the language than make use of such a tool. And I find that incredibly ironic.

Re:C++ Standards

[sjames]

I'm a bit late to the conversation, but I really want to know, how does dlsym deal with name mangling?

KDE5?

[pak9rabid]

How is this going to impact KDE? Will this be the start of KDE5?

Re:KDE5?

[Anonymous Coward]

All the development of Qt5 has been public and KDE is well aware of it. KDE5 has been in the plans for some time (more than a year), it will be done eventually.
But we don't have to worry, the transition from 4 to 5 won't be as traumatic as from 3 to 4 because no major changes are required, it will probably be pretty smooth.

Re:KDE5?

[NotBorg]

I read somewhere a while back that KDE was going to try to reduce the duplication of effort between KDE and Qt and rely more on Qt. I don't know where they're at with this but I'd like to here more.

Re:KDE5?

[NotBorg]

I'd like to hear more here, I mean.

Re:KDE5?

[Grishnakh]

Yes. KDE's major version number has always followed Qt's major version number. Don't worry, however; this isn't going to be like the KDE3->KDE4 transition at all. Instead, it'll look much like the KDE2->KDE3 transition (where they just updated the KDE code to compile against Qt3 instead of Qt2, and there were few major user-visible changes). KDE's only had two really huge revisions, and they were KDE2 and KDE4.

How is Qt still relevant?

[Andy Prough]

It's the framework for KDE, which is the excellent, fast UI environment I use on my Linux rigs. Apparently a huge number of other projects either use it currently, or have used it in the past, including a number of well-known projects: Amazon Kindle, Google Earth, Adobe Photoshop, MythTV, Rosegarden, Skype, Virtualbox, VLC media player.

Re:How is Qt still relevant?

[Trepidity]

Is it actually used on the Kindle? The only Qt-on-Kindle project I know of was an unofficial port which was abandoned by the maintainer two years ago.

Re:How is Qt still relevant?

[darronb]

Mine, also abandoned. I quickly stopped using the Kindle once it was obvious it was useless for viewing datasheets. http://www.griffin.net/2010/01/hacking-the-amazon-kindle-dx-part-2-qt-and-sudoku.html

Re:How is Qt still relevant?

[Andy Prough]

Nice work Darron - good proof of concept. Looks like some people did get some use out of the project.

Re:How is Qt still relevant?

[Vektuz]

On the business software side, there's also well known applications like Autodesk Maya (2011 and above, they switched TO qt recently!), and also the Perforce client (P4V). I'm seeing more and more of it in the internals of "big" apps like that, even if the user is unaware. I have a feeling its partly because of the LGPL side of things opening up more than anything. Although I'm pretty sure autodesk licensed it commercially.

Re:How is Qt still relevant?

[Anonymous Coward]

But KDE uses QWidgets which are being de-emphasized :-)

Re:How is Qt still relevant?

[Anonymous Coward]

I'd point out that Qt is a wonderful framework to program for.

I'm not sure so sure about the QML, but Qt widget system is quite wonderful. I expect Digia will go the way of the money, as opposed to Nokia who went... straight towards their own demise.

I did write some tests for QML and I can't claim it was bad, but now that MeeGo is more or less stagnant, it's just pointless. I just don't belive the touchscreen on devices larger than 7" will pick up, because they're too cumbersome and quite frankly, heavy.

Re:How is Qt still relevant?

[dotancohen]

It's the framework for KDE, which is the excellent, fast UI environment I use on my Linux rigs. Apparently a huge number of other projects either use it currently, or have used it in the past, including a number of well-known projects: Amazon Kindle, Google Earth, Adobe Photoshop, MythTV, Rosegarden, Skype, Virtualbox, VLC media player.

...Anki, Opera, Calibre, Stellarium, Krita...

Re:How is Qt still relevant?

[ChunderDownunder]

The 'Burning platforms' memo killed off Nokia's Qt deployment but 2013 will see 3 offerings:

- KDE Plasma Active running on Vivaldi
- Sailfish running on Jolla phones
- BB10 running on RIM phones

(Not to mention Canonical targeting 12.04 on Nexus 7 - Kubuntu on your tablet!)

So QML ain't extinct; it's just hibernating.

A glorious day

[mozumder]

This really is the best cross-platform Apps framework out there. Far better than HTML5/Javascript.

Re:A glorious day

[Flammon]

Far better than HTML5/Javascript.

I doubt it. Qt is nice but depending on what's being developed, HTML5/JavaScript can be the superior solution.

Besides, HTML5/JavaScript has so much momentum and is moving so fast that I'm afraid Qt will be irrelevant in a few years.

Check out this app.
https://moqups.com/
A native Qt app would have made the experience clumsy.

There are so many great JavaScript libraries in development that it's hard to pick one. Here are a few that you should keep your eye on though.
http://www.meteor.com/
http://angularjs.org/
http://emberjs.com/
http://dojotoolkit.org/
http://backbonejs.org/
http://jquery.com/

Re:A glorious day

[ikaruga]

I'm sorry but I couldn't see native code in any of these. Maybe for apps that use deals with small amount of text input, simple graphics, no peripheral hardware interfacing, have no intensive background processing and are running on very good cpus then that is okay. But for anything serious, just no.
Plus all these things are designed for webapps that run in a browser. Qt is for desktop apps. Comparing them is just stupid.

Re:A glorious day

[Urkki]

Far better than HTML5/Javascript.

I doubt it. Qt is nice but depending on what's being developed, HTML5/JavaScript can be the superior solution.

I think there are very few different cases where HTML5+JavaScript is superior. Online cloud-backed apps running in browsers are obviously one case, removing the need for separate download, and on native side there's the case where HTML+JS is the only alternative supported by all platforms where the application needs to run...

But HTML (any XML) is klunky compared to QML if you want to go the declarative route, and for "real applications" like the much-mentioned Autodesk Maya, they're not even competing because one of them is not an option at all, and will not be for a decade at least.

HTML5+JavaScript will probably get there, once processing power and memory of (mobile) devices goes up a bit more, and once the standard stabilizes (assuming it stabilizes instead of fragmenting...), and mobile networks become faster, and once the JavaScript libraries develop to be more sophisticated, and support for non-networked data storage gets better. A decade, maybe, considering the inertia.

standard compliance?

[stenvar]

So, is it fully standard C++ now or do you still have to use their hokey preprocessor?

Re:standard compliance?

[Anonymous Coward]

Does thinking of it as a bridge to all those not-quite-fully-standard compilers help overcome your disdain?

Re:standard compliance?

[loufoque]

It's still a moc'ery of C++, if that's what you're asking.
And it still duplicates everything that's in the standard library, including containers, threads, files, etc.

Re:standard compliance?

[Urkki]

So, is it fully standard C++ now or do you still have to use their hokey preprocessor?

Well, for many things Qt requires reflection features not provided with C++. When/if C++ starts to provide them as part of the language, I'm sure moc will become thing of the past, and be replaced with just translation data extractor, which you can leave out if you do not care about internationalization. But for what it's worth, with the new signal-slot connect syntax it's probably possible to have meaningful programs without running moc, if that makes someone happy.

Re:standard compliance?

[Anonymous Coward]

Fixed this for you:

And it still duplicates everything that's NOW in the standard library, including containers, threads, files, etc. for the set of compilers and run times that are compliant.

Re:standard compliance?

[suy]

So, is it fully standard C++ now or do you still have to use their hokey preprocessor?

Qt is, and always has been fully standard C++. The "moc" program is not a preprocessor, is just a tool, more precisely, just a code generator that writes for you some files that you have to either include at the end of your ".cpp" or you have to compile and link like other hand-coded files. If you use QMake, or CMake or any other buildsystem that has some Qt support (and most do), is completely effortless.

At a first glance, you see things that might look like an extension to the language, because you see stuff like "protected slots:" in addition to plain old public/private/protected C++. But here "slots" is just defined (using the standard C/C++ preprocessor) to an empty string, so the compiler sees the usual keywords only. Why is needed if is just an empty string? Well, because "moc" will use it when generating code.

Is possible to argue if all this (standard) preprocessor tricks are good or bad practice, but I have to say that it works for me. Qt has attemted to support a wide variety of environments, and the level of C++ support on those environments it's not the same. I even remember when TRUE and FALSE were provided as #defines because not all compilers had it. Right now I'm doing Qt development on an iMX23, and I'm quite constrained by the C++ compiler that Freescale provides, and I'm using Qt 4.8 just fine, the (till today) latest and greatest version.

Re:standard compliance?

[Anonymous Coward]

By duplicate you mean have a superior implementation, right? Qt is a modern framework with proper OOP, the sort anyone who's not a university teacher should kill to have. It's the standard enterprise-grade library C++ should always have had, if the purists hadn't ruined everyone's fun by not adding anything useful to the standard (though in their defense they started fixing mistakes in C++11 by adding threading) because it might hurt the feelings of people with 2-bob exotic platforms.

Enjoy using std::string in combination with a dozen non-member functions (some of which only available in Boost) to accomplish what are basic string manipulations in every modern language. I'll just use QString to get my FromX and ToX transformations, and UTF/localization support. Qt also provided easy, multiplatform multithreading long before C++11.

For the containers, they're all STL-compatible, so all your std algorithms work with them too, I don't see the big deal there.

Re:standard compliance?

[vurian]

Well, you might even amend it to "provides much better implementations of things that are in the STL, , including containers, threads, files, lists etc."

Re:standard compliance?

[shutdown -p now]

How exactly the magic Qt keywords like "slots" is implemented is really an implementation detail. From programmer's perspective, they are language extensions, because they introduce some new and important semantics into the language. The fact that they're handled by a separate codegen tool and stripped out of the code that's fed to the C++ compiler is irrelevant - you could just as well implement them directly in the compiler without changing their meaning, and it wouldn't magically change what they are.

Anyway, what's the difference? Even if they are language extensions, so long as they work and provide a useful feature, who cares?

Re:standard compliance?

[stenvar]

OK, sounds like nothing has changed.

Re:standard compliance?

[suy]

Yes, luckily good things like Qt didn't change, but unfortunately bad things like bashing Qt without making any point, and spreading misinformation (e.g. telling MOC is a preprocessor) didn't either.

Re:How?

[gmuslera]

One framework to rule them all, making programs for all platforms, including mobile ones, is a nice goal.

Finally fit!

[MouseTheLuckyDog]

"It's an overhaul of the Qt 4.x series and makes Qt fit for the future."

You mean to tell me that the old version of Qt were unfit?

Re:Finally fit!

[Kjella]

You mean to tell me that the old version of Qt were unfit?

Apparently it had far too little buzzword-compliance with their traditional widget-based imperative style GUI, now it's HTML/CSS/Javascript and declarative style GUI that is the "hot thing". I guess the good side is that it's like writing a web app that many developers know how to do but it has pretty much all the bad sides too, personally I find it's a giant step backwards. Or rather if I was going to do it this way I'd probably just go for HTML+JQuery and make it run in a browser against a back-end instead.

Re:Finally fit!

[lister king of smeg]

It's an overhaul of the Qt 4.x series and makes Qt fit for the future.

You mean to tell me that the old version of Qt were unfit?

there is a large difference between unfit and not as fit as it could be.

Re:Finally fit!

[shutdown -p now]

Declarative style GUI has been the "hot thing" for half a decade now.

And what's wrong about it? HTML5/JS is not bad because it's declarative. It's bad because HTML was never designed to lay out UI, and JS is just a quirky, horribly designed language. But do declarative UI with an expressive data binding framework, and use C++ (rather than JS) for the model, and it's beautiful.

Re:Finally fit!

[Isaac Remuant]

It was unfit for the future, yes.

Re:How?

[Anonymous Coward]

Because all other frameworks suck?

Scintilla?

[Anonymous Coward]

I've used wxWidgets/wxWindows in the past, and that has Scintilla built in. (Scintilla does syntax colouring for dozens of languages, allows bookmarks, breakpoint markers, etc, expand/collapse and is a good foundation for an IDE) I'm about to start a big project which includes a Lua editor/debugger, and now I'm wondering if I should look at Qt.

Does Qt 5 (or earlier) have a similar component to Scintilla? I presume it has all the other IDE-type stuff like docking panes, tab-based "notebooks", etc.?

Re:Scintilla?

[EvanED]

QScintilla is available for Qt4, though it's probably a separate package.

I can't speak to everything, but I will pretty highly recommend the library. I've used it in both C++ and Python (via PyQt) and both times have been a remarkably pleasant experience. The C++ side's biggest drawback is they have a preprocessing step (the MOC compiler) that means that you won't be writing code which isn't standard C++: they've got a bunch of language extensions. I wouldn't imagine that anything significant would be missing.

Re:Scintilla?

[AvitarX]

I will add that I love their sidebar docking, floating, tabbing, etc (see Eric IDE for a good example).

Eric makes use of QScintilla.

Re:Scintilla?

[Anonymous Coward]

In PyQt, QMainWidget has docks. QTabWidget does tabs. But they don't play along so you can't drag and drop a tab in the central QMainWindow widget as a dock.

I think QTextEdit processes HTML but I never used it that way so I'm not sure if JavaScript can be used... If it can, then you can use any JavaScript\CSS syntax highlighter but I don't code JavaScript so I wouldn't know. In python you could just glue in a JavaScript engine in half a dozen lines and output html through that... But in C++? probably 50 lines of boiler plate... Good luck :D

Re:Scintilla?

[Anonymous Coward]

Thanks guys. I'll look at Eric for inspiration :)

Re:Scintilla?

[RoccamOccam]

What about PySide? Is it mature enough to use for full-blown apps? Did PyQT change the licensing to make PySide irrelevant?

Re:Scintilla?

[pwizard2]

Yes, QTextEdit handles both HTML and plain text. If you want to export the current text as a full HTML document, you call toHTML(); and if you want plain text you call toPlainText(); Both methods produce a QString that has the text area contents.

Someone has probably already extended QTextEdit to make a drop-in widget that has better syntax highlighting. I know the same thing has been done for spell check.

Quicktime 5? Talk about old news

[Anonymous Coward]

Slashdot has really been behind the times lately but this realllly takes the cake. Quciktime 5 has been out since April of 2001 and they are up to 7.6.6. ;)

Signals and slots

[zenyu]

You can now use any C++ function as the target of a signal using the new QObject::connect() syntax. This is a huge win because with the new syntax the compiler and linker can check that the connections are valid instead missed connections just causing a run-time error.

The moc preprocessor is still required for QObject derived classes, mostly for the translation framework and also to provide support for the old signal/slot syntax which is still allowed. Qt5 doesn't require a C++11 compliant compiler, which is a good thing since there aren't yet any fully compliant compilers. I'm sure if there is a Qt6 it will require C++11 and use those features.

Some of the really cool C++11 features like move constructors aren't necessary with Qt because it's containers implement reference counted copy-on-write, so when you assign a QMap from another QMap no copy is made, and if the old QMap was an rvalue then there is never a need for the copy to be made when the new QMap is modified. One of the big improvements Qt4 made over Qt3 was to make container assignment atomic so this mechanism worked with threaded code and defensive deep copies weren't necessary anymore.

Re:Signals and slots

[shutdown -p now]

Qt5 doesn't require a C++11 compliant compiler, which is a good thing since there aren't yet any fully compliant compilers. I'm sure if there is a Qt6 it will require C++11 and use those features.

C++11 is not necessary for MOC-less signals/slots - Boost has been offering them for years with all existing compilers.

Some of the really cool C++11 features like move constructors aren't necessary with Qt because it's containers implement reference counted copy-on-write, so when you assign a QMap from another QMap no copy is made

Sure, but what about your own types? Implementing COW is much harder than implementing a move constructor. I do hope that Qt containers use move semantics for elements when available, at least?

Also, COW is not free when it's thread-safe. Those atomic increments and decrements do add up, especially on instances of types that are copied around a lot (strings are a classic example of that).

Re:Signals and slots

[Urkki]

Sure, but what about your own types? Implementing COW is much harder than implementing a move constructor.

In case you are genuinely interested, it's not hard, because there's a helper class for that: QSharedDataPointer

Re:Signals and slots

[shutdown -p now]

That helps. On the other hand, if you use that trick (copying pointer to actual data around), you get the overhead of an extra indirection on every field access, as well as a heap allocation for every instantiated obejct (even if it's instantiated on stack). As I understand, Qt pretty much has to do it anyway for its classes to enable binary compatibility between minor releases via the usual Pimpl idiom, but it's not necessarily desirable for user classes.

You're right.

[Andy Prough]

It's an add-on. My bad. By the way, I think the better port is here: http://www.griffin.net/2010/01/hacking-the-amazon-kindle-dx-part-2-qt-and-sudoku.html

Awesome

[Vektuz]

QT is about the best "native SDK" I've seen out there. In the company I work at, we dev our internal tools in Qt, and at home my hobby projects are in Qt also. They run on mac, linux, and windows. Other projects that run on Qt include Maya (Autodesk), they recently swapped over to using 4.7.1. Knowing autodesk, in only a couple decades they'll switch to Qt5!

Re:Awesome

[pwizard2]

I'm still using 4.7.4 and I intend to do so for a long time. My main reason is to keep pace with the Debian repositories (4.7 support was recently added to testing, stable still has 4.6). For the past year I've been working on an app that won't build on 4.6 b/c of new features added to 4.7, meaning support in Debian Stable was out unless you roll your own Qt. Anything I write for Qt 4.7 will probably compile fine with Qt5 (if necessary) or run under Qt5 libs so I see no reason to upgrade.

How is Qt Quick?

[dannydawg5]

I used Qt Quick briefly. It seems like you get a lot of deep powerful customization, but that comes at a cost. It eventually pissed me off so I went back to QWidget, and my productivity soared.

I would not have completed my project in a reasonable time using Qt Quick. It is not "quick". Sometimes, you just want to drop tables, check boxes, buttons, etc. on to your main window, tie the click event to a slot, and call it done. You are fine with whatever default styling and rendering that Qt and the OS decide is appropriate for the widget's click/hover/etc event.

It seems with Qt Quick, you have to specify all that nonsense. Plus, the Qt Quick editor tool felt complex and confusing. I avoided it and did everything by hand. Qt Designer for QWidgets is a drag-n-drop breeze. I even got my manager on board after he saw me using it. He is an EE, and he really likes it. He is used to spending $500 on Visual Studio Pro to what Qt Designer does better for free.

Maybe I just needed to study Qt Quick more to get past the learning curve, but I knew how to do it the widget way, and I wanted the project done.

Has anybody had success migrating their project from QWidgets to Qt Quick? Unless I see a strong compelling reason, I am sticking with QWidgets. It works really well for me.

Re:How is Qt Quick?

[Anonymous Coward]

I didn't do anything with Qt Quick yet besides of reading some docs and opinions, at this time is more oriented to do fancy things for mobile, but IMHO is not a replacement for QWidgets yet, however a guy is working on it since almost two years ago:

http://blog.qt.digia.com/blog/2011/03/10/qml-components-for-desktop/

Re:How is Qt Quick?

[Anonymous Coward]

It's perfectly fair to use QWidgets. I think it's awesome that the framework provides full support for widgets while exploring and improving QtQuick. Today QtQuick is good for those who want full customisation - which means a lot of embedded apps our there - and it's also moving in the direction of providing standard components (see Qt Components) that work better with the RAD model that Designer, Widgets and Signals/Slots are built around.

Widgets are there, but will fade with the years as they are very rigid and hard to animate. QtQuick is awesome for that but needs a few more years to fully replace widgets.

Re:How is Qt Quick?

[Anonymous Coward]

I used Qt Quick briefly. It seems like you get a lot of deep powerful customization, but that comes at a cost. It eventually pissed me off so I went back to QWidget, and my productivity soared.

I would not have completed my project in a reasonable time using Qt Quick. It is not "quick". Sometimes, you just want to drop tables, check boxes, buttons, etc. on to your main window, tie the click event to a slot, and call it done. You are fine with whatever default styling and rendering that Qt and the OS decide is appropriate for the widget's click/hover/etc event.

It seems with Qt Quick, you have to specify all that nonsense. Plus, the Qt Quick editor tool felt complex and confusing. I avoided it and did everything by hand. Qt Designer for QWidgets is a drag-n-drop breeze. I even got my manager on board after he saw me using it. He is an EE, and he really likes it. He is used to spending $500 on Visual Studio Pro to what Qt Designer does better for free.

Maybe I just needed to study Qt Quick more to get past the learning curve, but I knew how to do it the widget way, and I wanted the project done.

Has anybody had success migrating their project from QWidgets to Qt Quick? Unless I see a strong compelling reason, I am sticking with QWidgets. It works really well for me.

A lot of this is coming up in the 5.1 release. You might be interested in watching http://www.youtube.com/watch?v=Y1pqL5bXe0A

Re:How is Qt Quick?

[shutdown -p now]

My understanding is that the big problem with Qt Quick is the lack of all the usual widgets. There really isn't any particular reason why you shouldn't be able to define QML graphs in terms of "I want this button here and this textbox there", and them assuming the default theme etc.

Re:How is Qt Quick?

[slack_justyb]

If you are use to using QWidget and that is what you are comfortable with, then there is absolutely zero need for you to try and pick up Qt Quick. Qt Quick is really good at building one offs that you need for small tasks, think million little widgets here, not database editor. Qt5 is still centered very much around C++ and the people who wrote Qt are very aware that Qt Quick "is not for everyone".

You may find yourself pulling up Qt Quick for implementing a "find dialog" or a "insert criteria dialog", but if you are writing the main window in Qt Quick, you either have a very modular/small project or you are using the wrong tool for the job. The best way I tell others is that Qt Quick is for doing up quick UIs, not complicated UIs. Qt Quick would be excellent for Palsmoids, horrific for an entire email application (unless you have really broken the program down to very small bits.)

As an example, I have a program that we use here in the office to connect to PostgreSQL. The connect to dialog is Qt Quick, the window with all the tables and fields is pure QWidgets. The fill-in-the-form order request window is Qt Quick, the order summary window is QWidgets (mostly because it has all kinds of sort and filter buttons). So keep the Qt Quick stuff small and simple and you will find that it's nice to use for all those one offs that do not need a lot of logic behind the window.

That is not to say that Qt Quick *cannot* do a large application, just that it will be easier to continue to do so with QWidget, and that is the whole point, to make things easier. Also, I strongly encourage you (and for that matter anyone seriously looking at Qt) to pick up some C++11. Qt 5 has been written to make logical use of some of the newer stuff in C++11 and those concepts do very much indeed make your code very, very clean. I will admit that I was quite skeptical at first about that point.

Re:How is Qt Quick?

[Urkki]

Has anybody had success migrating their project from QWidgets to Qt Quick? Unless I see a strong compelling reason, I am sticking with QWidgets. It works really well for me.

For an existing project, I think the only compelling reason would be, if you want a bling-bling GUI for touch interaction. Think of flick scrolling, multi-finger zoom&pan, animated transitions. And then it would need to be a complete UI redesign.

But, in 1-2 years, I think almost all new displays even on desktop, and certainly on laptops, will be touch screens. I think this is a good time to start thinking about a full UI re-design for any application, where displaying information is important.

Re:How is Qt Quick?

[vurian]

Often it's possible to do both. For Krita, which has been around as a QWidget application for more than ten years now, it was possible to make a Qt Quick-based version in about four months with two people: Krita Sketch, which offers almost all the functionality of Krita Desktop, but touch-enable.

Re:How is Qt Quick?

[Anonymous Coward]

I believe there will be a desktop widgets module in qt 5.1 that provides common widgets and native styling. tbc...

Re:How?

[rocjoe71]

Hey, several of my favoruite Windows apps are in Qt (e.g. from my WinXP days: "Launchy", and current versions of TweetDeck and Calibre).

Qt-on-Windows runtime installs much like the Visual C++ runtime, and that, for me, is preferable over any app done in Java/Perl/Python, as I don't have to clutter up my system with RTEs (that are all too often supporting a single app)

...and not one annoying "time to update your runtime... AGAIN" ... ever!

Re:How?

[TemporalBeing]

How is Qt still relevant?

Let's see...

It's the only multi-platform development kit that is really as feature complete as most platforms.

It runs on more devices than you'd ever imagine - from small embedded devices to your kitchen appliances to mobile devices to desktops and servers.

It's what KDE is built on.

It's what MeeGo/Mer/Tizen/Sailfish are built on.

It's what Blackberry 10 (BB10) is built on.

AutoDesk is built on it.

CiscoVPN is built on it (well, a really old version at least).

There's plenty more out there; but I'm going to stop there.

Re:How?

[StripedCow]

One framework to rule them all

But for Android and iOS support, we'll have to wait until late 2013.

Re:How?

[Deus.1.01]

Lighthouse?

Does Qt 5 adhere better to OS X UI conventions?

[Anonymous Coward]

I wonder if Qt 5 will adhere better to OS X (Macintosh, Apple) user interface guidelines. Previous versions of Qt have stomped on OS X conventions at seemingly _every_ possible opportunity.When I see an app that I'm considering using is made with Qt, I shudder. I'm never sure that it is Qt to blame or the developer, but I'll bet that it is mostly Qt. In my opinion, it is a horrible cross platform solution, but somewhat less horrible than some of the others. A Windows-using friend of mine says that it also sucks on Windows and that he thinks it's mainly a Linux thing.

some of the best documentation ever

[Anonymous Coward]

I must admit, as someone who has coded in Qt, that is has some of the best documentation I've ever seen (from a developer's perspective). Just look at the docs on Containers . There's diagrams, examples, tables, and pictures.

Re:Oh Noes, KDE 5.0

[Anonymous Coward]

Yes, because all prior releases define future releases. And since every major software product has at least one version that sucked in some way, every release from that point on will suck forever.

IE 10 sucks because there was a 6. Firefox 17 sucks because there was a 4. Windows 7 sucks because there was ME, Vista, and 8 (Shit, why not go backwards too since we're not making sense anyway). Gnome will never recover from 3 and Unity... well I guess it sucks if you fuck up on 1.0.

god damned trolls.

Re:How?

[Isaac Remuant]

For support, kinda. But you can already deploy for android with necessitas.