Project not building on windows

Creaperdown

Hey, I am currently working on a project, which works all fine on linux, but doesnt seem to build on windows.

The error messages I get are:

I wouldnt exactly know what code to provide. What I am building is this: https://github.com/Librum-Reader/Librum.
Does anyone have an idea why these errors could occur?

I noticed that it shows me (at the bottom of the error message), that there is an undefined reference to my signals, which I find weird, since I use the Q_OBJECT macro in all my classes

Thanks in advance

Christian Ehrlicher

Wouldn't it be better to ask the author of the project?

Creaperdown

@Christian-Ehrlicher Well, I am the author

kkoehne

"undefined reference" errors on Windows are usually related to the fact that, on Windows, you have to explicitly export and import symbols if these symbols are used across library/module boundaries.

See also https://doc.qt.io/qt-6/sharedlibrary.html

Creaperdown

@kkoehne I see, I'll try this. Is it generally enough to put Q_DECL_EXPORT infront of every class I want to use from another binary?

SGaist

Hi,

Not Q_DECL_EXPORT but yes you have to export all the classes you want to use from your library.

See how it is done in the documentation @kkoehne linked.

ali-aydin

Hi,
it maybe depend on your access permission to Storage

SGaist

@ali-aydin said in Project not building on windows:

Hi,
it maybe depend on your access permission to Storage

No it's not. If it was access permission related, @Creaperdown wouldn't be able to build the library in the first place.

Creaperdown

@kkoehne I've tried following the docs on a small project I set up (which has the same issue, I think my other project has) but it still doesnt work. https://github.com/Creapermann/Temp

kkoehne

@Creaperdown , I just successfully compiled the latest HEAD (d5e98b8c6cc17abe) of your repository on Windows, with MinGW and MSVC:

C:\dev\tmp\Temp>cmake -B mingw-build -GNinja -DCMAKE_PREFIX_PATH=C:\Qt\6.3.1\mingw_64 .
-- The CXX compiler identification is GNU 11.2.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Qt/Tools/mingw1120_64/bin/c++.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE
-- Performing Test HAVE_STDATOMIC
-- Performing Test HAVE_STDATOMIC - Success
-- Found WrapAtomic: TRUE
-- Found WrapVulkanHeaders: C:/VulkanSDK/1.2.176.1/Include
-- Configuring done
-- Generating done
-- Build files have been written to: C:/dev/tmp/Temp/mingw-build

C:\dev\tmp\Temp>cmake --build mingw-build
[21/21] Linking CXX executable appTesting.exe

What compiler are you using, and what is the exact compiler output you get?

Creaperdown

@kkoehne I am using the same setup you do. I have Qt 6.3.1 and am using mingw_64. When I am running the exact same command you do, in the command line, I get following error:

cmake -B mingw-build -GNinja -DCMAKE_PREFIX_PATH=C:\Qt\6.3.1\mingw_64 .
-- The CXX compiler identification is GNU 6.3.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/MinGW/bin/c++.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:22 (find_package):
  Could not find a configuration file for package "Qt6" that is compatible
  with requested version "6.2".

  The following configuration files were considered but not accepted:

    C:/Qt/6.3.1/mingw_64/lib/cmake/Qt6/Qt6Config.cmake, version: 6.3.1 (64bit)



-- Configuring incomplete, errors occurred!
See also "C:/Users/prtnp/Programming/Temp/Temp/mingw-build/CMakeFiles/CMakeOutput.log".

Do you have an idea why this doesnt work? Looking around I only find that not using CMAKE_PREFIX_PATH could cause this, but I do.

Also, when using QtCreator, it compiles but it doesnt run. Does the application run for you?

Creaperdown

Also, I've realized I am using mingw_64, which exports all symbols by default, so I don't think that exporting the symbols is the problem. Does anyone have another idea?

cristian-adam

In your compilation example you have:

-- The CXX compiler identification is GNU 6.3.0

Please use a newer MinGW. The one from Qt SDK should be 11.2.0.

In your temp project you have:

find_package(Qt6 6.2 COMPONENTS Quick REQUIRED)

Please remove the 6.2 part, which doesn't play well with Qt version 6.3.1 given via -DCMAKE_PREFIX_PATH=C:\Qt\6.3.1\mingw_64.

kkoehne

@cristian-adam said in Project not building on windows:

Please remove the 6.2 part, which doesn't play well with Qt version 6.3.1 given via -DCMAKE_PREFIX_PATH=C:\Qt\6.3.1\mingw_64.

I think this should actually be fine, because 6.3.1 is compatible with 6.2, and no EXACT is set.

But yes, the GCC compiler version is too old.