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TrollTech Releases Qt 3.0
Dr. Sp0ng writes: "TrollTech released Qt 3.0 today. Among the new features are platform- and database-independent data-access features, data-aware GUI widgets, a much-updated Qt Designer, and much better internationalization and font handling features. It breaks binary compatibility but keeps almost complete source compatibility with Qt 2.x. The KDE team has already begun work on KDE 3.0, which will use the new toolkit."
How far would Microsoft have gotten if they "broke binary compatibility" with major releases of Windows? Basically, not far at all. That's not to say that Windows has perfect backward compatibility, but I don't think it's too strong a statement to say that one of the reasons Microsoft has dominated is that they have given people an upgrade path for their old applications.
Of course, the downside to this philosophy is the incredibly crufty interfaces to a lot of the Windows functionality. But I think it's key to point out that users don't care at all about those things -- they just care that their applications work.
If the desktop dreamers ever want to see Linux on the desktop, then they need to not destroy everyone's applications if you want to upgrade. Just telling everone to "recompile your applications" is not going to fly well with the typical user.
Sometimes it's best to just let stupid people be stupid.
While having open-source code makes source compatibility easier to handle than binary compatibility, I've been wondering if there has been any work towards improving binary compatibility between versions of major libraries.
This is an issue with C++... since most of KDE's widgets are subclasses of Qt widgets, they are very dependant on the signature of the Qt class. When the class signature changes (for example, when a function is added or removed, or a data member is added), the derived class needs to be recompiled or the linking will be all screwed up. This isn't an issue between minor revisions of the library as the API is stabilized, but with a major jump (2.3.1 -> 3.0), the API or implementation changes and things must be recompiled.
It's impressive that TrollTech (which is a great company, btw) managed to keep source compatibility so well. I'm a professional developer and we're using Qt for our app (which is currently ~20,000 lines), and exactly *1* line of code needed to be changed when we moved from 2.3.1 to the 3.0 betas.
You may write commercial/proprietary/non-free software only if you have purchased the Professional or Enterprise Edition. Qt for Windows is only available as Professional or Enterprise Editions.
So, basically, you can (have to) pay to get away from the GPL/QPL/whatever their license is called these days.
They also sell training.
See http://www.trolltech.com/developer/faqs/general.ht ml?cr=1
Ryan T. Sammartino
"Ancora imparo"
OK, not so many points as I thought...
The short answer is yes, there has been. The biggest problem has been with the C++ libraries, and g++ is finally standardising on a stable ABI.
As for Trolltech, they've always worked hard to maintain binary compatiblity (eg minor releases are binary compatible), indeed there were more
problems with binary compatiblity caused by libstdc++ issues than with Qt itself. I'm not
sure that KDE has been as stable, though this
should improve. (The move to DCOP resulted in growing pains)
To get some appreciation of how fragile binary compatibliity is, read this. Binary compatibility is fundamentally
difficult to preserve in C++, and I don't think there's any clean way around it. Fundamental
changes in interface or exposed structure
(that means anything besides opaque pointers) will break binary compatibility.
Personally, I think the fundamentals need to be
nailed down. C++ and C libraries need to preserve
binary compatiblity. On the other hand, I don't
think there's a problem with other libraries, so long as they maintain binary compatiblity across minor releases. (users could install multiple versions of the same library)
QT is not free for cross platorm freeware.
Earlier we did not had a very good choice for cross platform GUI, AWT/SWING did not have the performance of native GUI and WxWindows was not powerfull/rich enough.
Then came QT and I thought wow ! this is it, for my next cool application, eventhough I will develop it on Linux, I can make it available for Windows as well as Mac users.
Then I realised its only free on X, you got to pay around 1500$ to get it on other platforms even if you want to write/ditribute a freeware app.
On Windows you pay 50$ after rebates to get a copy of VisualC++ 6.0. And for 50$ you get a compiler, GUI class library, and IDE and debugger. And just for the QT library its 30 times more than Visual C++, how can any hobby programmer afford it ?
I hope Trolltech come out with a more sensible pricing for freeware developers on Windows/Mac which should help QT to gain more acceptance in the non Linux programming community as well.
Sun deserves a lot of credit. If you're going to introduce a Revolutionary New Approach to Programming, you shouldn't do it with inefficient, buggy VMs, or quickie compilers that don't properly exploit garbage collection. Thos mistakes gave Java a reputation for flakiness and inefficiency it still hasn't fully dispelled.
And if you want everybody to start using Java to develop desktop apps, you don't suddenly shut down your own application development efforts before they've had a chance to bring their product to market. But of course IBM, Oracle, and all the other biggies were doing that too. Coinciding with the downfall of the Network Computer.
And that's what really went wrong with desktop Java. Platform independence was never enough by itself to make Java widely adopted on the desktop. You had to give people a reason to abandon their investment in Windows-based solutions. That reason, was the Java-based NC, which was supposed to lower the Cost of Ownership for big corporate computer buyers. (And, not incidentally, give these same buyers a reason to buy proprietary Sun and IBM hardware instead of commodity PCs.) Unfortunately, nobody bought the NC idea, and the main market for Java desktop apps disappeared.
Some, but not all, of this history is repeating itself with Qt and KDE. Being technically superior to Windows wasn't enough for Java, and it won't be enough for the Linux desktop.