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  1. #1
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    Jan 2008
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    16

    Qt for Symbian^3

    Hi,

    We hv developed some Qt applications in the S60V5 platform (N97 SDK v1.0)

    all features are working fine, and hv Symbian signed.

    And now we want to port the app to Symbian^3 platform (SDK v 0.8)

    We successfully built and packaged the sis, but we got problems when we test on N8.

    Many graphics cannot be loaded, and after several actions a prompt "Memory full" is shown on screen.

    This problem only exist in N8, but not in S60v5 platforms.

    I wonder if it is the memory problem of the N8,

    however we hv tested another Symbian based apps which contains much much more graphics,

    and everything are working fine, without any "Memory full" prompt.


    Just want to know if Symbian^3 is fully support Qt now?

    Or still in beta version that having the above strange problems?

    Thanks a lot.

    Edwin Mak
    Zensis Ltd,
    www.zensis.com

  2. #2
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    Oslo
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    Re: Qt for Symbian^3

    Hi,

    This is most likely not a problem with the memory on the N8. Qt renders via OpenVG on the N8 which ironically uses more process memory than using the "raster" graphics system which is used on all devices before the N8. The raster graphics system stores much of it's data in the FBSERV shared heap while the OpenVG graphics system uses your process's heap more extensively (doesn't use FBSERV at all). The most likely problem here is that your process (not the phone) is running out of memory. Can you try increasing the EPOCHEAPSIZE in the .pro file to see if this makes the error go away?

    http://doc.trolltech.com/4.6/qmake-v...t-epocheapsize

  3. #3
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    Re: Qt for Symbian^3

    I have set the following in the mmp already:

    EPOCHEAPSIZE 0x020000 0x800000

    Since I hv another version running in 5800,

    if the problem is due to this EPOCHEAPSIZE,

    then I should get the error in 5800 too .....

  4. #4
    Nokia Developer Champion
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    Minnesota, USA
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    Re: Qt for Symbian^3

    Graphics failures is a classic sign of running out of heap. Oddly, though, the application will (usually) keep running without panic after it "runs out" of heap, still consuming more heap (just not able to load new graphics and a few other things).

    This situation is made much worse if your application has a heap leak (and there's at least one leak in the current Qt support, for scrolled lists).

  5. #5
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    Re: Qt for Symbian^3

    so that's Qt problem?

    As the app can run properly in S60v5 devices...

  6. #6
    Nokia Developer Champion
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    Re: Qt for Symbian^3

    On Symbian you can query heap size with Symbian native C++.
    Code:
    #ifdef Q_OS_SYMBIAN
    #include <e32std.h>  // Link against euser.lib
    #endif
    ....
    #ifdef Q_OS_SYMBIAN
    	TInt mem, size, limit;
    	User::Heap().AllocSize(mem);
    	size = User::Heap().Size();
    	limit = User::Heap().MaxLength();
    	ui.memLabel ->setText(QString::number(mem));
    	ui.memLabel ->update();
    	ui.sizeLabel ->setText(QString::number(size));
    	ui.sizeLabel ->update();
    	ui.limitLabel ->setText(QString::number(limit));
    	ui.limitLabel ->update();
    #endif

  7. #7
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    Re: Qt for Symbian^3

    Did modifying the EPOCHEAPSIZE solve the problem on the N8? You may not see the problem on the 5800 because as I mentioned previously it uses Qt's raster graphics system which attempts to store data in the FBSERV heap rather than in your process's heap so it has a lower requirement on EPOCHEAPSIZE.

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