[dotnet-sig] Re: Error: Qt_5_PRIVATE_API and dotnet !

[Omair Majid]

Hi,

Thanks for sharing this!

Cătălin George Feștilă <catalinfest(a)gmail.com&gt; writes:

>  I try a basic example with QML - https://github.com/qmlnet/qmlnet
>  And I need to fix this error , any idea ? 
I think this is a bug in Qml.Net.

>   ---> System.Exception: Library could not be loaded:
> /lib64/libQt5Core.so.5: version `Qt_5_PRIVATE_API' not found (required by
> /home/mythcat/CSharpProjects/QMLProjects/QML001/bin/Debug/net6.0/runtimes/linux-x64/native/libQmlNet.so):
> /home/mythcat/CSharpProjects/QMLProjects/QML001/bin/Debug/net6.0/runtimes/linux-x64/native/libQmlNet.so
This says that libQmlNet.so is trying to open libQt5Core.so.5 but
couldn't find (symbols with?) version Qt_5_PRIVATE_API. That's the
version in the libQt5Core.so that ships with Ubuntu.

I grabbed Ubuntu's libQt5core5a package [1] and looked at it locally:

    $ eu-readelf -V ./usr/lib/x86_64-linux-gnu/libQt5Core.so.5.9.5
    ...
    Version definition section [ 6] '.gnu.version_d' contains 13 entries:
     Addr: 0x0000000000062630  Offset: 0x062630  Link to section: [ 4] '.dynstr'
      000000: Version: 1  Flags: BASE   Index: 1  Cnt: 1  Name: libQt5Core.so.5
      0x001c: Version: 1  Flags: none  Index: 2  Cnt: 1  Name: Qt_5_PRIVATE_API
    ...

Fedora's libQt5Core.so.5 uses a different version: Qt_5.15.2_PRIVATE_API

    $ eu-readelf -V /usr/lib64/libQt5Core.so.5
    ...
    Version definition section [ 7] '.gnu.version_d' contains 19 entries:
    Addr: 0x0000000000074e70  Offset: 0x074e70  Link to section: [ 5] '.dynstr'
     000000: Version: 1  Flags: BASE   Index: 1  Cnt: 1  Name: libQt5Core.so.5
     0x001c: Version: 1  Flags: none  Index: 2  Cnt: 1  Name: Qt_5.15.2_PRIVATE_API
   ...

It looks like that Qml.Net has built their library in such a way that it
requires an exact version which makes it only work on Ubuntu (and
probably Debian). You should report this as a bug to them so they can
fix this and make Qml.Net work on Fedora (and other Linux distributions)
too.

[1]
http://security.ubuntu.com/ubuntu/pool/main/q/qtbase-opensource-src/libqt...

Omair

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