@JoeCFD
thank you so much for your reply. you save me from this problem.
i solve this by removing other mingW compiler and it work properly.

I figure out this is because of Q_Object macro I added in those files.
I don't know why the macro doesn't work maybe better open another post.
in other posts people suggest to rerun the qmke to solve this problem but doesn't work for me
anyone know why Q_Object macro doesn't work for android?

@ComixHe No problem. Oh, you also said that you now need C++17. Yes, the minimum language version requirement in Qt6 was bumped from C++11 to C++17. It makes a lot stuff easier, the implementation can be cleaner and it is supported by all major compilers anyway.

so with help of someone from BugReport portal, the solution was extremly simple...
as you can see form the log:
eea6d5ef-d2db-4406-8d50-50e2ca9c185a-image.png
C and C++ compler is pucked up from PERL, not form MinGW,
so I have onlymoved MinGW environment variables PATH above the PERL and then all worked fine...

they also suggested to try specify:

-DCMAKE_CXX_COMPILER=C:/path/to/mingw/compiler/g++.exe -DCMAKE_C_COMPILER=C:/path/to/mingw/compiler/gcc.exe

but im not sure where to put this realy.

other option (im only thinking, was not suggested) is to use MingwDir parameter in configure

but not sure if the Qt is this smart enough to use this parameter as a compiler path for C and C++, this has to be tested realy

I have created a bug report regarding this. I used the minimal example that you have created in the bug report. Thanks for sharing your minimal example.

https://bugreports.qt.io/browse/QTBUG-111968

It's a hand-written parser. It doesn't need to understand all of C++ though, because it's only interested in class declarations etc.

As @jsulm pointed out, it's open source, see https://code.qt.io/cgit/qt/qtbase.git/tree/src/tools/moc :)

@Dariusz said in cmake automoc + dll... error LNK2001: unresolved external symbol "public: static struct QMetaObject:

Do I have to write some kind of post build command that copies all moc files to some location & ship it with my dll/include folder?

no, the moc data is compiled into your binary, like any other class/method etc.

Since you are using cmake, did you set the AUTOMOC property?!
https://doc.qt.io/qt-6/cmake-get-started.html

@mattfbacon said in MOC: signals and slots can't be on same line:

Really, moc should be using a full C++ parser...

Again: feel free to provide a patch instead blaming around that a corner case does not work...

:( but thanks for the links.

@SGaist Hi, Thank you for your reply. I understand your point, so I set this topic solved.

I just realized that C:\Qt\Licenses\LISENSE do not include the GPL v3 exception stated above. Hence, the argument above does not hold.

Hi,

It might be of interest and would likely benefit from a plugin in Qt Creator. However the first step would be to have it build various Qt project types.

Note that cmake won't be transitional. It's going to be the build system of Qt 6 and thus it's going to stay like this for the whole Qt 6 lifetime at least. Just take a look at the lifetime of qmake.

@Quentin91 said in can the moc compile a class flagged as Q_OBJECT in Visual Studio Express 2017 ?:

But I've seen that the Express version of VS doesn't support it... probably.

plugin support was added in recent versions of VS Community.

Hey

Nope not yet. Will try it, just need to learn it :- )

Well, a class name is not a unique identifier since it's already used to name said class.

One more thing: this should have been one of my first things I tried, but I ran the debugger and got the following message - "The inferior stopped because it received a signal from the operating system
Signal name: SIGSEGV
Signal meaning: Segmentation fault",

and it pointed directly at my destructor for DataPiece, which simply calls "delete this" (even though I never actually call the destructor in my code, it must be an implicit call).

After briefly looking up this error, I primitively discovered that this generally occurs when attempting to illegally access a register in memory. So then I looked at how I initialized my DataPiece, realizing that I actually wasn't calling any of my constructors. So, I passed it a parameter 'this' to act as the QObject * parent, but this still didn't resolve my SIGSEGV issue.

Any thoughts?

You have to use the correct moc to your headers. When you install Qt you must also install the devel tools for this specific Qt versions. And you should fix your buildsystem to call moc. Those moc files do no belong to the sources.

I heard opposing arguments to that when it comes to moc/rcc/uic. Personally, I use the set(CMAKE_AUTOMOC ON) way

@jsulm Some good options there.
I shall look into them.
Many thanks for your help!