Problem building apps with S^3 SDK 0.9 for S60 5.x phones

[timokauppinen]

Tried to compile and build a simple helloworld with Symbian ^3 SDK 0.9.
Everything seems to go fine. Installed the SIS to N97 mini.
Icon is shown in the app list but when I try to start it, nothing happens.
Even removed the icons but still the same problem occurs.

When I build the same app with S60 3x or 5.x SDK, it's working fine.

Is this a known compatibility problem between the S^3 and older S60 platforms?

[symbianyucca]

You should not build application with newer platform version SDK. Thus if you are planning to support 5th ed devices, do build the application with 5th ed SDK.

[wizard_hu_]

Indeed, backward compatibility means that new devices can run many applications built with older SDK-s. However there is no such promise in the other way, code built with new SDK-s might run on older devices, but it is not promised or expected.
Note that 'does not work' would not be enough anyway, you should always try to enable the error messages on the device, as described here: http://wiki.forum.nokia.com/index.ph...ded_panic_code (you need the same approach which applies to S60 3rd and 5th editions).

[ltomuta]

Please go through http://tinyurl.com/StartSymbian
It is a old resource but still valid, and should put you into the right track when it comes to Symbian development.

[timokauppinen]

At first, sorry for this poor description of the error.

- In fact, I'm already enabled the "errrd" and I can see the panic codes in normal cases. This time, no panic dialogs is shown in the screen.
- the application is just a simple "helloworld" app taken from old platform and definitely not using any new S^3 features.
- the only difference I've seen in the SIS file is the EXE file. So somehow the created binary is not compatible with N97. So maybe it's the SBSv2 or RVCT that makes the EXE incompatible?

This is the first time I ever see this kind of problem during my 8-year career of Symbian development. And building the same app N97 SDK works well even in S60 3.0 phones. I was trying to ask if somebody else has successfully build an application with S^3 SDK for older S60 devices.

[symbianyucca]

the point is that you should not build apps with newer SDKs for older devices, you should take the SDK that is for the oldest devices you want to support, and then use only the APIs that are in the public SDK as well as APIs that are not marked as depricated in any platform version you are supporting with that specific executable.

Anyway, if errrd does not give you any note, you can always see what Y-Tasks::Crash monitor gives to you.

[tamhanna]

This is the first time I ever see this kind of problem during my 8-year career of Symbian development. And building the same app N97 SDK works well even in S60 3.0 phones. I was trying to ask if somebody else has successfully build an application with S^3 SDK for older S60 devices.

Sorry for my long awayness.

This is due to the special situation that S60v5 is nothing but S60v3 with a hastily touchscreen addon. S^3 brings more under the hood changes!!!

[timokauppinen]

The original question still remains unanswered.

Since, at least in this test, very basic classes are used and the BC should be still maintained, there is no clear reason why S^3 could not be used for compiling apps also for S60 3.x and 5.x phones.

There are lots of reason why this should be solved. One is e.g building Qt 4.7 applications. It would be just too troublesome to adjust the earlier platforms to be able to compile that very same app for 3.x and 5.x platforms. That would save lots of time and trouble for many developers.

I will do some deeper investigation to solve the problem. Or if it turns out be impossible, I hope to find the specific reason for incompatibility.

[timokauppinen]

When I compared the outputs with ELF2E32, I saw two clear differences:
- EPOC Exe for ARMV4 CPU (S^3: ARMV5)
- Export Description: Size=000, Type=00 (S^3: Type=01)

So I will try to define the target CPU for SBS and/or RVCT to see if that helps.
Possibly all this trouble is just in my environment but let's see what will be found..

[ltomuta]

The original question still remains unanswered.

Since, at least in this test, very basic classes are used and the BC should be still maintained, there is no clear reason why S^3 could not be used for compiling apps also for S60 3.x and 5.x phones.

Timo, you seem to have (still) the wrong understanding regarding the binary compatibility promise. We promise backward compatibility and we work hard for each platform release to ensure that we maintain this promise. Each SDK has a list of BC breaks,most of them planned and carefully calculated, some accidental and unavoidable. But that is backwards compatibility only, i.e. existing applications are verified to work with the new platform release, without a need for rebuild.

We do not promise, nor do we ever verify for, forward compatibility. And that is your problem today. You may have been lucky until now, but it seems your luck is over. Time to return to best practices and if you chose to work with one SDK only then make sure that the SDK you use is the one that offers you most compatibility.

There are lots of reason why this should be solved. One is e.g building Qt 4.7 applications. It would be just too troublesome to adjust the earlier platforms to be able to compile that very same app for 3.x and 5.x platforms. That would save lots of time and trouble for many developers.

I will do some deeper investigation to solve the problem. Or if it turns out be impossible, I hope to find the specific reason for incompatibility.

Nokia Qt SDK would be the SDK to use for building Qt applications targeting all Nokia's devices. However, that SDK is recommended for pure Qt code only (not so much for calls to Symbian OS APIs) and does not support Qt 4.7 for Symbian yet. If you want to experiment with Qt 4.7 then probably you should try with the S60 3.1 SDK, that should ensure that even if you call OS specific APIs the app will be still compatible with all the devices supporting Qt.

[timokauppinen]

This is well understood, but I would still prefer to know the actual reason for the failure.
Not just obscure "this is not just working" excuses.

Please let me finish the analysis first.

[ltomuta]

By all means, let us know what you find.

[tamhanna]

Hi,
if you provide me with a writeup and send me an emtial to tamhan at tamoggemon dot com, I will run it on my somewhat large Symbian developer blog!

All the best
Tam Hanna

[timokauppinen]

Everything was working fine with clean S^3 toolset: SBS 2.14.2 and RVCT 4.0 b771.
The application was tested this time in a S60 3.1 phone.

I will check the other environment later to see if e.g. different SBS or RVCT version makes this fail.

---

Currently I'm not certain at all if the build was successful after all. I have no idea how did I build it, since I'm not able to make it work again. But all this is no longer an issue, since I managed to build a QML app with QtCreator, patched with Qt 4.7 rc1 for Symbian. I hope an official release will be out soon.

[timokauppinen]

Something worth to try: maybe it's all about ABIv1/v2 difference?

http://library.forum.nokia.com/index...migration.html

abld build armv5_abiv1
or edit file \epoc32\tools\variant\variant.cfg