Qt vs Symbian C++
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What do you think would happen to Symbian C++, would it continue to exist? Would Qt complement it in someway or completely replace Symbian C++ ?
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I finde Symbian C++ to be a lot less straightforward than Qt. I can see Qt taking a fair amount of developers away from Symbian C++, but I don't think it will replace it.
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As far as c++ application development is concerned Qt will replace symbian c++. As others pointed out, it is much more easier and is cross platform. With Symbian 4, the S60 avkon framework will not be supported and Qt will be the only choice for building guis for c++ applications. For Symbian c++ apis other than GUI, you may mix them with Qt code if needed. But that will be rare, with Qt mobility available.
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Remaining use cases for Symbian C++:
- If you need a rock-solid stable background server (because Qt doesn't have any mechanism for handling out-of-memory issues yet)
- Accessing platform APIs which aren't available via Qt Mobility.
- Supporting old devices (there are still some out there that Qt won't run on, particularly in poorer countries)
That's about all I can think of.
Basically, if you can use Qt then do!
Mark (Kernel & Base Technology Manager at the Symbian Foundation)
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Thanks Mark and Jaykrishnan,
If an app is targeted for the current crop of Symbian devices and requires accessing platform APIs, Symbian C++ can be used. However, if the app is heavy on UI, Qt would be a better option. That is the best I could summarize it.
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I'd go further than that - if there is ANY UI, and you can use Qt, then do use Qt. Don't write a new UI in Symbian C++ unless you absolutely have to.
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Just in - there is a firmware update for the N900 and it contains the Qt 4.6.2 libraries. So no need to bundle the core with the app :-)
However, that still leaves this question open - how will Qt help provide rich UI apps to the existing millions of Symbian devices ?
One may say, by adding the Qt libraries to the app, but that would make the size of the app around 8 MB + which is not so good with devices with limited memory like the N97.
Qt is not so much backward compatible, it's applicability to future devices seems assured.
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Have you checked Symbian smart installer for Qt ? With this, there is no need to bundle Qt with your app. At the installation time, the smart installer downloads and install Qt if Qt is not already installed on the phone. I haven't used it yet. So I don't know how good it works. If anybody have used it, it will be good if they can share their experience
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I have read about the smart installer, it was at beta 2.0. Whether one bundles the Qt libraries with app code or uses the smart installer, eventually the libraries will be installed on the phone memory. The current footprint is around 8 MB, which on phones like the N97, is quite a lot.
I have tried installing the qt_installer.sis ( this is available in the latest beta SDK) and it always installs in the C: drive, not the mass memory.
I think in future iterations of Qt, it is important for the libraries to be able to run on mass memory, the end user should have this choice.
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bq. I think in future iterations of Qt, it is important for the libraries to be able to run on mass memory, the end user should have this choice.
It is not that easy as You say it is. Please correct me if I’m wrong but usually the devices mass memory is some kind of Flash NAND, in witch case every code stored in this memory needs to be copied in to the devices RAM memory. On the other hand the devices C: drive is usually some kind of Flash NOR, witch can store XIP code (eXecute in Place), this cuts the start-up time substantially because there is no need to copy the code in to RAM.
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To be honest, I have no idea about the differences between how code executes on C:\ vs on the mass memory. But there are so many apps, specifically those written in Symbian C++, which install on either memory just as easily.
Qt, on the other hand, currently does not do that. It somehow installs only on the C:\ drive.
I would hope and expect, in the future, that installing Qt apps on either of these memories be possible.
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[quote author="varunnarula" date="1275402178"]I would hope and expect, in the future, that installing Qt apps on either of these memories be possible. [/quote]
You can easily install Qt applications at mass memory. But Qt libraries should be better installed at c:\ (even if they will work at mass memory) because of performance issues.
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I have tried installing the qt_installer.sis which comes with the (beta) Qt SDK and during installation, the option is provided, but I noticed that all the library components installed on the C: drive.
Have you tried installing any Qt application (bundled with the Qt libraries) on the mass memory. Do let me know, this is something I want to try out.
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Have not tried apps bundled with qt libs, but installing at first qt libs (on main memory) and at second qt app (on SD-card) worked well.
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[quote author="kkrzewniak" date="1275206164"]
It is not that easy as You say it is. Please correct me if I’m wrong but usually the devices mass memory is some kind of Flash NAND, in witch case every code stored in this memory needs to be copied in to the devices RAM memory. On the other hand the devices C: drive is usually some kind of Flash NOR, witch can store XIP code (eXecute in Place), this cuts the start-up time substantially because there is no need to copy the code in to RAM.
[/quote]
No, I'm afraid you are wrong. For many years now the C: drive and the Z: drive (which is where the ROM runs from) have been on NAND flash and are copied to RAM before they run. Typically NOR flash is too slow for modern processors and too expensive compared to NAND + more RAM.A good reason not to store the Qt libs in mass memory is because on some devices that might be a removable card and then any apps installed to C: that needed the libs wouldn't work when the card was removed.
The proper solution to this problem is for Nokia to stop creating devices with too little space on C:!
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bq. The proper solution to this problem is for Nokia to stop creating devices with too little space on C:!
That is exactly the problem. 128 MB will just not cut it. At the very least, 256 MB is required. The N900 has some virtual memory, any idea if something similar can be done on Symbian ?
Take the N97 for example, and with Maps, Quickoffice, Qt and browser cache, the memory quickly fills up. With virtual memory, this problem could be solved.
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No, you're confusing RAM and Flash. Symbian does have virtual memory in the form of demand paging and specifically Writable Data Paging in Symbian^3. That will mean more free RAM but it doesn't help with the amount of space on C: (in fact it could make it worse because that data has to be paged out to flash somewhere!).
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[quote author="varunnarula" date="1275576380"]I have tried installing the qt_installer.sis which comes with the (beta) Qt SDK and during installation, the option is provided, but I noticed that all the library components installed on the C: drive.
Have you tried installing any Qt application (bundled with the Qt libraries) on the mass memory. Do let me know, this is something I want to try out.[/quote]
There was an issue with qt_installer.sis and it need to be installed on c: only. It was said to be fixed in the newer versions.
However, apart from this you can install any Qt Application in the mass memory.
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[quote author="varunnarula" date="1276181289"]bq. The proper solution to this problem is for Nokia to stop creating devices with too little space on C:!
That is exactly the problem. 128 MB will just not cut it. At the very least, 256 MB is required. The N900 has some virtual memory, any idea if something similar can be done on Symbian ?
Take the N97 for example, and with Maps, Quickoffice, Qt and browser cache, the memory quickly fills up. With virtual memory, this problem could be solved.
[/quote]
I do agree N97 has memory issues. But I think most new devices will handle these issues now.
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The qt_installer.sis was from the beta 1 of the Qt SDK released recently. Have yet to try the one from the latest beta, I believe it is 2.0.