Build and Run from Command Line

Sebastiano Zamberlan

What is the correct way to launch from 0 the build and then run of a Qt6 project (Cmake) via command line.

Take for example a QtQuick Application project

How can i from Powershell build and then run the project?

sierdzio

@Sebastiano-Zamberlan the process is similar to any other cmake project:

cmake -S /path/to/source-code -B . 
cmake --build . --parallel --config Release

Then you either run the executable right away or perhaps run deployment first (windeployqt).

Sebastiano Zamberlan

@sierdzio How can I specify that I want it to be compiled with mingw_64

Christian Ehrlicher

@Sebastiano-Zamberlan said in Build and Run from Command Line:

How can I specify that I want it to be compiled with mingw_64

What does this mean? You create a CMakeLists.txt like it's done in QtCreator or any other ide which cmake then processes.

Sebastiano Zamberlan

@Christian-Ehrlicher, @sierdzio let's take an example, I create a new project ( in this case QtQuick Application )
I leave the code as is and try from terminal to run

cmake -S /path/to/source-code -B .

this is what appears to me.

-- Building for: Visual Studio 15 2017
-- Selecting Windows SDK version 10.0.17763.0 to target Windows 10.0.19045.
-- The CXX compiler identification is MSVC 19.16.27051.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x86/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:8 (find_package):
  By not providing "FindQt6.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Qt6", but
  CMake did not find one.

  Could not find a package configuration file provided by "Qt6" (requested
  version 6.2) with any of the following names:

    Qt6Config.cmake
    qt6-config.cmake

  Add the installation prefix of "Qt6" to CMAKE_PREFIX_PATH or set "Qt6_DIR"
  to a directory containing one of the above files.  If "Qt6" provides a
  separate development package or SDK, be sure it has been installed.


-- Configuring incomplete, errors occurred!

I wanted to know meanwhile how to specify my intention to use mingw_64 as compiler

Christian Ehrlicher

You have to set up your env correctly before by starting the command line through the 'Qt 6.x.x (MinGW64) menu entry. Then the PATH is correctly set up and the mingw compiler is found & used. Start over with a clean build dir.

Sebastiano Zamberlan

@Christian-Ehrlicher @sierdzio

I tried but still the same error,
I also ran the command

--system-information information.txt

and in the .txt the path goes to the Visual Studio

In fact the message that cmake sent me was always:

-- Building for: Visual Studio 15 2017

Christian Ehrlicher

@Sebastiano-Zamberlan Then pass -DCMAKE_CXX_COMPILER=g++ and make sure g++ --version print something useful (which should when you set up the env correct).

SGaist

Hi,

In addition to @Christian-Ehrlicher, the Qt 6 versions you installed have a qt-cmake script that are tuned for the installation they are in.

Paul Colby

@Sebastiano-Zamberlan said in Build and Run from Command Line:

@sierdzio How can I specify that I want it to be compiled with mingw_64

The easiest way, I think, is to use CMake's MinGW Makefiles generator, like:

cmake -G "MinGW Makefiles" ...

As @SGaist wrote, if you're using Qt 6, then you can use Qt's qt-cmake wrapper, so:

X:\path\to\qt\installation\qt-cmake.bat -G "MinGW Makefiles" -S <src-dir> -B <build-dir>

All qt-cmake does (today) is set CMake's CMAKE_TOOLCHAIN_FILE variable, so it's equivalent to:

cmake.exe -DCMAKE_TOOLCHAIN_FILE="X:\path\to\qt\installation\lib\cmake\qt.toolchain.cmake" -G "MinGW Makefiles" -S <src-dir> -B <build-dir>

Cheers.

Sebastiano Zamberlan

@Paul-Colby @Christian-Ehrlicher @SGaist @sierdzio

Thank you guys, this information is very helpful,

I was able to launch from the specific terminal, now I want to understand what the "qtenv2.bat" contains and how it acts so that I can make a .bat or a general .py that allows me to launch a build.

jsulm

@Sebastiano-Zamberlan said in Build and Run from Command Line:

I want to understand what the "qtenv2.bat" contains and how it acts

Open it in a text editor

Sebastiano Zamberlan

@jsulm yeah 👍