linker error in vs code

[kamran78nasirizad]

I wrote this program in vs-code for testing.

#include <QtWidgets/QApplication>
#include <QtWidgets/QPushButton>

int main(int argc, char **argv){
    QApplication app (argc, argv);
    QPushButton button ("Hello world !");
    button.show();
    return app.exec();
}

the c_cpp_properties.json file is:

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**",
                "C:/Qt/6.5.0/mingw_64/include"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE"
            ],
            "compilerPath": "C:\\msys64\\mingw64\\bin\\gcc.exe",
            "cStandard": "c17",
            "cppStandard": "gnu++17",
            "intelliSenseMode": "windows-gcc-x64"
        }
    ],
    "version": 4
}

and the tasks.json file is:

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: g++.exe build active file",
            "command": "C:\\msys64\\mingw64\\bin\\g++.exe",
            "args": [
                "-fdiagnostics-color=always",
                "-g",
                "${file}",
                "-I",
                "C:/Qt/6.5.0/mingw_64/include",
                "-L",
                "C:/Qt/6.5.0/mingw_64/lib",
                "-o",
                "${fileDirname}\\${fileBasenameNoExtension}.exe"
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "Task generated by Debugger."
        }
    ],
    "version": "2.0.0"
}

but I got these errors

Starting build...
C:\msys64\mingw64\bin\g++.exe -fdiagnostics-color=always -g E:\3_Document\Codes\C++\GameOfLife\main.cpp -I C:/Qt/6.5.0/mingw_64/include -L C:/Qt/6.5.0/mingw_64/lib -L C:/Qt/6.5.0/mingw_64/lib/cmake -o E:\3_Document\Codes\C++\GameOfLife\main.exe
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\aas\AppData\Local\Temp\ccUP2mrt.o: in function `main':
E:/3_Document/Codes/C++/GameOfLife/main.cpp:5: undefined reference to `__imp__ZN12QApplicationC1ERiPPci'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: E:/3_Document/Codes/C++/GameOfLife/main.cpp:6: undefined reference to `__imp__ZN11QPushButtonC1ERK7QStringP7QWidget'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: E:/3_Document/Codes/C++/GameOfLife/main.cpp:7: undefined reference to `__imp__ZN7QWidget4showEv'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: E:/3_Document/Codes/C++/GameOfLife/main.cpp:8: undefined reference to `__imp__ZN12QApplication4execEv'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: E:/3_Document/Codes/C++/GameOfLife/main.cpp:9: undefined reference to `__imp__ZN11QPushButtonD1Ev'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: E:/3_Document/Codes/C++/GameOfLife/main.cpp:9: undefined reference to `__imp__ZN12QApplicationD1Ev'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: E:/3_Document/Codes/C++/GameOfLife/main.cpp:9: undefined reference to `__imp__ZN11QPushButtonD1Ev'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: E:/3_Document/Codes/C++/GameOfLife/main.cpp:9: undefined reference to `__imp__ZN12QApplicationD1Ev'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\aas\AppData\Local\Temp\ccUP2mrt.o:C:/Qt/6.5.0/mingw_64/include/QtCore/qversiontagging.h:125: undefined reference to `__imp_qt_version_tag_6_5'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\aas\AppData\Local\Temp\ccUP2mrt.o: in function `QString::QString(char const*)':
C:/Qt/6.5.0/mingw_64/include/QtCore/qstring.h:1029: undefined reference to `__imp__ZN7QString8fromUtf8E14QByteArrayView'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\aas\AppData\Local\Temp\ccUP2mrt.o: in function `QByteArrayView::QByteArrayView<char, true>(char const*, long long)':
C:/Qt/6.5.0/mingw_64/include/QtCore/qbytearrayview.h:137: undefined reference to `__imp__Z9qt_assertPKcS0_i'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:/Qt/6.5.0/mingw_64/include/QtCore/qbytearrayview.h:137: undefined reference to `__imp__Z9qt_assertPKcS0_i'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\aas\AppData\Local\Temp\ccUP2mrt.o: in function `QtPrivate::QPodArrayOps<char16_t>::destroyAll()':
C:/Qt/6.5.0/mingw_64/include/QtCore/qarraydataops.h:95: undefined reference to `__imp__Z9qt_assertPKcS0_i'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:/Qt/6.5.0/mingw_64/include/QtCore/qarraydataops.h:96: undefined reference to `__imp__Z9qt_assertPKcS0_i'
C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/13.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\aas\AppData\Local\Temp\ccUP2mrt.o: in function `QTypedArrayData<char16_t>::deallocate(QArrayData*)':
C:/Qt/6.5.0/mingw_64/include/QtCore/qarraydata.h:124: undefined reference to `__imp__ZN10QArrayData10deallocateEPS_xx'
collect2.exe: error: ld returned 1 exit status

Build finished with error(s).

how I can solve it?

[Axel Spoerl]

@kamran78nasirizad
Probably the widget library is not linked in the CMake file (or not added if you use qmake).
Can you show the CMakeLists.txt or the .pro file?

[kamran78nasirizad]

@Axel-Spoerl

there is no .txt or .pro file in project

[Axel Spoerl]

@kamran78nasirizad
Oh, sorry, I completely overlooked that you are using vscode. The issue remains the same: the Qt shared libraries are not linked. But I do not know vscode at all. Maybe this helps.

[cristian-adam]

You need to either use both MinGW and Qt from Msys2 or from Qt.

Currently you are mixing the compiler from Msys2 and Qt from the Qt SDK.

Please do install MinGW from the Qt SDK and you should not have compatibility issues.

But instead of using -I and -L with the Qt include and lib paths you might want to use a CMake preset with vscode. Or just use Qt Creator 😅

[8Observer8]

I use Sublime Text 4 for regular coding as it requires the least resources of my laptop. My laptop works silently with this editor. It helps me in learning Qt because there is no autocomplete in the editor. There is an autocomplete plugin for Sublime Text 4 but I don't want to use it. I use Qt Creator when I need to debug a program, or when I need to create an APK (Android executable), or when I need to debug a program on an Android emulator.

You need to check how your application compiles from the console:

• Add a target name to your .pro file: TARGET = app
• Navigate to your project folder from the console and type: qmake -makefile
• Compile your code: mingw32-make
• Run the application: release/app

I think you will have the same errors as above. Add these paths to the Path variable:

C:\Qt\6.2.4\mingw_64\bin
C:\Qt\Tools\mingw1120_64\bin

P.S. To open a window with your Path variable, you can copy this command: rundll32 sysdm.cpl,EditEnvironmentVariables and paste it into the Far Manager console. In this case, you can very quickly open a window with your Path variable by typing run in the Far Manager console, and autocomplete will add the rest of the command, since Far Manager will save the command after the first time the command is run.

P.S.S If you need to output something to the console with std::cout from Windows from a program that you run from the console, you need to add this code to main.cpp:

#ifdef _WIN32
#include <windows.h>
#endif

#include "main_window.h"
#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
#ifdef _WIN32
    if (AttachConsole(ATTACH_PARENT_PROCESS))
    {
        freopen("CONOUT$", "w", stdout);
        freopen("CONOUT$", "w", stderr);
    }
#endif
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

[kamran78nasirizad]

@cristian-adam
how I must install minGW from QT SDK and how I must use CMake preset in vs-code?
my Qt Creator free trial is finished and I no longer have access to it and as I know it is not free any more

[jsulm]

@kamran78nasirizad said in linker error in vs code:

Qt Creator free trial

QtCreator is open source and free to use for everyone.
To install MinGW simply use Qt Maintenance Tool from your Qt installation.

[kamran78nasirizad]

@jsulm when I open the Qt creator this message shown.
and if I click on close the entire program would close

[JonB]

@kamran78nasirizad
I think you need to explain exactly what/how you installed Qt. Also had you installed any other version of Qt on that machine at an earlier date?

[jsulm]

@kamran78nasirizad Please explain how you installed QtCreator...

[kamran78nasirizad]

I went to the Qt.io website, and clicked on the "Download. Try." button, then in "https://www.qt.io/download" I clicked on "Download Qt for Windows", and after completing the form and downloading the Qt installer ran it.

Is this the wrong method to download and install Qt and Qt Creator?

[kamran78nasirizad]

@JonB No the system was fresh before installing this Qt.

[jsulm]

@kamran78nasirizad said in linker error in vs code:

Is this the wrong method to download and install Qt and Qt Creator?

You should go to https://www.qt.io/download-open-source and download the installer from there.