Error on Qt 6 Building from source for Windows Based

Lemat

or what is the right compiler path ? this one ?: C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.28.29333\bin\Hostx64\x64

jsulm

@Lemat I think that path is correct. Visual Studio itself is a x86 application, but it has compiler which generates x86_64 binaries.

Lemat

@jsulm all right

Lemat

should i set a real compiler path in the system environment variable CXX ?? i don't know the real compiler file name. my actual Qt 5.15.2 has detected it automatically. i am looking in her settings to find the compiler file name, but nothing.

jsulm

@Lemat I don't think so. It should work as described on that web page. I don't know why it doesn't work for you.

Lemat

i really need help for that. i tried anything, but nothing. Maybe cmake version ?

Lemat

Tools used:
Cmake version: 3.18.4 x64
Python: 3.7.3 x64
ActivePerl: 5.28 x64
Ninja: 1.10.2

SGaist

Hi,

IIRC, cmake 3.19.2 or newer is recommended but I don't have the source at hand.

Lemat

@SGaist

Can you explain more ?

SGaist

You should update your cmake version.

Lemat

@SGaist

Okay. let me try. i am downloading cmake 3.19.3

Lemat

i tried with cmake 3.19.3, problem still exist

SGaist

Did you restart from a clean state ?

Lemat

@SGaist yes. i did it. but the problem still exist

SGaist

What did you do to ensure a clean state ?

Lemat

I Installed Qt 6.0.1 with the online Installer. Too bad for me. Many features such as QWebEngine are removed

eyllanesc

@Lemat That and other modules will be added in the new versions during the year, read https://www.qt.io/blog/add-on-support-in-qt-6.0-and-beyond. So you have 2 options: 1) wait or 2) manually compile the modules

Lemat

@eyllanesc ,that is okay !. i just leaned on doc.qt.io. Waiting is the best option for me after failing on this subject title. laugh.

Christian Ehrlicher

Use 5.15 and you're fine. Don't know why everyone needs to use Qt6 when it's documented that it's not feature complete... Qt6 does not have any advantage for an average user at the current state.

Chris Kawa

This is the do_it.bat I'm using to build Qt6. Adjust the paths and configure options at the top to whatever you like. You only need to have CMake in PATH, nothing else, or you can just spell out its path right in the bat script.

SET VS_ENVIRONMENT="C:\Program Files (x86)\Microsoft Visual Studio 2019\VC\Auxiliary\Build\vcvars64.bat"
SET SRC_DIR="C:\Qt\6.0.1\Src"
SET BUILD_DIR="C:\Qt\6.0.1\Build"
SET INSTALL_DIR="C:\Qt\6.0.1\msvc2019_64"
SET CONFIGURE_OPTIONS=-debug-and-release -mp -opensource -confirm-license

call %VS_ENVIRONMENT%
mkdir %BUILD_DIR%
mkdir %INSTALL_DIR%
cd %BUILD_DIR%
call %SRC_DIR%\configure -prefix %INSTALL_DIR% %CONFIGURE_OPTIONS%
cmake --build . --parallel
cmake --install .
cmake --install . --config Debug
cd %INSTALL_DIR%
rmdir %BUILD_DIR% /Q /S
pause

This builds Qt out of source (the only sane way to do it cleanly), copies result to the install directory and removes the temporary build directory (which can get huuuge if you're building everything).

Some notes on the discussion points above:

Depending on your version of VS (Pro, Cmmunity etc.) the VS install dir will look a bit different. If in doubt just find "x64 Native Tools Command Prompt for VS 2019" shortcut in your start menu and see where it points to
There are couple of different .bats to set VS environment. For x64 build use either vcvarsall.bat amd64 or a shortcut vcvars64.bat
Keep source and build directories next to each other e.g. <some path>\src and <some path>\build. Theoretically it should be possible to build out of source to anywhere, but I've had multiple problems with mismatched number of .. and the likes in the past so keep it this way just to make it easier for yourself.
It's a good idea to exclude whichever modules you don't need in configure options e.g. -skip qtdatavis3d. I usually use only about 3-5 modules and exclude everything else, which cuts down compilation time and output size immensely.