vcpkg + Qt + Cmake + Visual Studio 2019

Question

I am trying to install Qt6 using vcpkg, and use it in a Visual Studio 2019 CMake project. I have tried linking other libraries (ex: fmt) and it worked. However, when I add Qt in the mix, building succeeds, but running the executable fails:

the popup shows:

Program ... QtCored.dll
...
This application failed to start because no Qt platform could be initialized
...

and the console says

qt.qpa.plugin: Could not find the Qt platform plugin "windows" in "C:\vcpkg\installed\x64-windows\Qt6\plugins\platforms"
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Environment variables: I set VCPKG_ROOT to C:\vcpkg, QT_PLUGIN_PATH to C:\vcpkg\installed\x64-windows\Qt6\plugins\platforms, QT_QPA_PLATFORM_PLUGIN_PATH to C:\vcpkg\installed\x64-windows\Qt6\plugins\platforms, added C:\vcpkg\installed\x64-windows\Qt6 and C:\vcpkg to the path.

I tried putting the exe in a separate folder, and running windeployqt.exe on it, but it fails as well...

windeployqt.exe C:\Users\broland\Desktop\NewFolder\HelloWorld.exe

Warning: Translations will not be available due to the following error.
Cannot open C:/vcpkg/installed/x64-windows/translations/Qt6/catalogs.json
Unable to find dependent libraries of C:\vcpkg\installed\x64-windows\bin\Qt6Widgetsd.dll :Cannot open 'C:/vcpkg/installed/x64-windows/bin/Qt6Widgetsd.dll': The system cannot find the file specified.

My CMakeLists.txt:

cmake_minimum_required (VERSION 3.8)

set(CMAKE_AUTOMOC ON)  # https://stackoverflow.com/questions/14170770/unresolved-external-symbol-public-virtual-struct-qmetaobject-const-thiscal
set(CMAKE_INCLUDE_CURRENT_DIR ON)  # so that mainwindow.h and mainwindow.cpp is seen

project (HelloWorld)

find_package(fmt CONFIG REQUIRED)

find_package(Qt6Core REQUIRED)
find_package(Qt6Gui CONFIG REQUIRED)
find_package(Qt6Widgets REQUIRED)

add_executable (HelloWorld "helloworld.cpp" "helloworld.h" "mainwindow.cpp")
#add_executable (HelloWorld "mainwindow.cpp" "mainwindow.h" "mainwindow.cpp")

target_link_libraries(HelloWorld PRIVATE fmt::fmt)
target_link_libraries(HelloWorld PRIVATE Qt::Gui)
target_link_libraries(HelloWorld PRIVATE Qt::Core)
target_link_libraries(HelloWorld PRIVATE Qt::Widgets)

Been trying for days. Any suggestions?

Answer 1

So, instead of using vcpkg, I installed Qt through the online installer.

For anyone else struggling, I will leave this here. I followed parts of this and this tutorials.

Since I use Visual Studio, I downloaded the MSVC 2019 64-bit version. I set the environment variable QTDIR equal to the path where msvc2019_64 folder lies. I added to the Path env. var. %QTDIR%\lib and %QTDIR%\bin. To check if I can link other vcpkg installed libraries, I got OpenCV (vcpkg install opencv). It seems to work. The path in INCLUDE is where I have the respective file, ip, ua and var are folders of my project containing source and header files.

My CMakeLists.txt:

cmake_minimum_required (VERSION 3.8)

project (OpenCBDependencyTest)

#some magic
set(CMAKE_AUTOMOC ON)
#set(CMAKE_INCLUDE_CURRENT_DIR ON)
INCLUDE(C:/vcpkg/scripts/buildsystems/vcpkg.cmake)  # so that vcpkg installed packages are seen


# find packages
find_package(Qt6Core REQUIRED)
find_package(Qt6Gui REQUIRED)
find_package(Qt6Widgets REQUIRED)

find_package(OpenCV REQUIRED)


# include files
set(IP_DIR "${CMAKE_SOURCE_DIR}/ip")
set(UA_DIR "${CMAKE_SOURCE_DIR}/ua")
set(VAR_DIR "${CMAKE_SOURCE_DIR}/var")

include_directories(${IP_DIR})
include_directories(${UA_DIR})
include_directories(${VAR_DIR})

file(GLOB_RECURSE SOURCES
    "${IP_DIR}/*.cpp"
    "${IP_DIR}/*.h"
    "${UA_DIR}/*.cpp"
    "${UA_DIR}/*.h"
    "${VAR_DIR}/*.cpp"
    "${VAR_DIR}/*.h"
    "Main.cpp"
)
add_executable (OpenCBDependencyTest ${SOURCES})


# link libraries
target_link_libraries(OpenCBDependencyTest Qt::Core)
target_link_libraries(OpenCBDependencyTest Qt::Gui)
target_link_libraries(OpenCBDependencyTest Qt::Widgets)

target_link_libraries(OpenCBDependencyTest ${OpenCV_LIBS})