Unable to compile using Mingwx64 on windows, Command line option error

[Dariusz]

Hey

It seems to me like Qt configuration for mingw is somehow broken and it adds command lines to cmake & cause mingw to go bananas.

Some other peron has the same error here > https://stackoverflow.com/questions/67824944/unrecognized-command-line-option-zc-cplusplus-and-unrecognized-command-line

I'm on Clion & Mingwxt64 qt 6.1.2

Problems were encountered while collecting compiler information:
	c++.exe: error: unrecognized command line option '-Zc:__cplusplus'
	c++.exe: error: unrecognized command line option '-permissive-'; did you mean '-fpermissive'?

Can any1 hint out on how can I fix this?

[VRonin]

Are you trying to compile your project or the Qt library itself?
Can you post your CMakeLists?

[Dariusz]

@VRonin Hey I've simply changed my compiler from msvc to mingw64. Im trying to run my app. Using precompiled mingw64 binaries from qt installer. I tried using both mingw shipped ith QT, and latest official one. Both have issues

Here is most of my Qt related cmake code > it currently "has issues" with dlls given some of them don't exist under mingw, but thats to fix after I get it to build without the darn error :- (

set(sp "-----  ")
set(QT_PATH "C:/Qt/6.1.2/")
if (MSVC)
    # warning level 4 and all warnings as errors
    #add_compile_options(/W4 /WX)
    set(QT_PATH ${QT_PATH}msvc2019_64)
    message(\n ${sp} "IM IN MSVC")
else ()
    # lots of warnings and all warnings as errors
    message(\n ${sp} "IM NOT IN MSVC")
    #add_compile_options(-Wall -Wextra -pedantic -Werror)
    add_compile_options(-Wno-error=unknown-warning)
    #set(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "")
    #set(CMAKE_SHARED_LIBRARY_LINK_CXX_FLAGS "")
    #set(CMAKE_C_COMPILER_WORKS 1)
    set(QT_PATH ${QT_PATH}mingw81_64)
endif ()



set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} ${QT_PATH})

set(LIB_MODE STATIC)
set(GLOBAL_ROOT ${CMAKE_SOURCE_DIR})

set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)

set(QT_USE_QTGUI TRUE)
set(QT_USE_QTXML TRUE)

set(QT_VERSION 6)
set(REQUIRED_LIBS Core Widgets Gui Network OpenGL)
set(REQUIRED_LIBS_QUALIFIED Qt6::Core Qt6::Widgets Qt6::Gui Qt6::Network Qt6::OpenGL)
ADD_DEFINITIONS(-DQT_NO_KEYWORDS)
ADD_DEFINITIONS(${QT_DEFINITIONS} -DQT_MESSAGELOGCONTEXT)
ADD_DEFINITIONS(-D_USE_MATH_DEFINES)

message("\n\n")
message(${sp} "CORE CMAKE IMPORT")
message(${sp} "Global Root : " ${GLOBAL_ROOT})
message(${sp} "QT          : " ${QT_PATH})
message(${sp} "")
message(${sp} "FindPackage QT : " "Qt${QT_VERSION}" " COMPONENTS : " "${REQUIRED_LIBS} " "REQUIRED")
message("\n\n")

find_package(Qt${QT_VERSION} COMPONENTS ${REQUIRED_LIBS} REQUIRED)


message(\n\n ${sp} "Qt Prep\n")
# Import QT dlls/etc
if (WIN32)
    set(DEBUG_SUFFIX)
    if (CMAKE_BUILD_TYPE MATCHES "Debug")
        set(DEBUG_SUFFIX "d")
    endif ()
    set(QT_PATH ${CMAKE_PREFIX_PATH})
    message(${sp} "DEBUG_SUFFIX " ${DEBUG_SUFFIX})
    if (EXISTS "${QT_PATH}/bin")
        file(MAKE_DIRECTORY "${GLOBAL_ROOT}/libOutput/test/plugins/platforms")
        file(MAKE_DIRECTORY "${GLOBAL_ROOT}/libOutput/plugins/platforms")
        file(COPY "${QT_PATH}/plugins/platforms/qwindows${DEBUG_SUFFIX}.dll" DESTINATION "${GLOBAL_ROOT}/libOutput/plugins/platforms")
        file(COPY "${QT_PATH}/plugins/platforms/qwindows${DEBUG_SUFFIX}.dll" DESTINATION "${GLOBAL_ROOT}/libOutput/test/plugins/platforms")
        file(COPY "${QT_PATH}/plugins/platforms/qwindows${DEBUG_SUFFIX}.pdb" DESTINATION "${GLOBAL_ROOT}/libOutput/plugins/platforms")
        file(COPY "${QT_PATH}/plugins/platforms/qwindows${DEBUG_SUFFIX}.pdb" DESTINATION "${GLOBAL_ROOT}/libOutput/test/plugins/platforms")
        foreach (QT_LIB ${REQUIRED_LIBS})
            set(filePath ${QT_PATH}/bin/Qt${QT_VERSION}${QT_LIB}${DEBUG_SUFFIX}.dll)
            get_filename_component(barename ${filePath} NAME)
            if (NOT EXISTS "${GLOBAL_ROOT}/libOutput/test/${barename}")
                message(${sp} "Copying file : " ${QT_PATH}/bin/Qt${QT_VERSION}${QT_LIB}${DEBUG_SUFFIX}.dll to Tests)
                file(COPY "${filePath}" DESTINATION "${GLOBAL_ROOT}/libOutput/test")
            elseif (NOT EXISTS "${GLOBAL_ROOT}/libOutput/${barename}")
                message(${sp} "Copying file : " ${QT_PATH}/bin/Qt${QT_VERSION}${QT_LIB}${DEBUG_SUFFIX}.dll to Root)
                file(COPY "${filePath}" DESTINATION "${GLOBAL_ROOT}/libOutput/")
            else ()
                message(${sp} "Skipping copying of ${barename}")
            endif ()
        endforeach (QT_LIB)

    else ()
        message(${sp} WARNING " COULD NOT FIND QT LIBS! ")
    endif ()
endif ()

[VRonin]

My eyes are burning! especially the # Import QT dlls/etc part.
There is no add_library/add_executable here so I have no clue what that CMakeLists is doing

[Christian Ehrlicher]

Also you can't simply switch the compiler - you need the correct Qt for it. -Zc:__cplusplus is a msvc option.

[Dariusz]

@VRonin Hahahha I know :d I'm in process of slowly... learning to update it.

This part essentially copies all qt dlls I need into the exe location of my app

The add_executable(${PROJECT_NAME} ${SRC}) is just that < There is nothing else that I do

I forgot to add the link part to the code above which is >

#### QT
function(linkQTLibs)
    target_link_libraries(${PROJECT_NAME}
            ${REQUIRED_LIBS_QUALIFIED}
            )
endfunction()

But after that its zip.

Esentially its

Cmake:

project(Hello world)
set(CMAKE_CXX_STANDARD 20)

include("pathToCmake/CmakeList.txt") # Which is the one posted in previous post 
set(SRC main.cpp)
add_executable(${PROJECT_NAME} ${SRC})
linkQTLibs()

And that's it.

I don't set any more flags/etc. Its rather "simple" build.

[Dariusz]

@Christian-Ehrlicher In the cmake post above there is (clean up now) >

set(QT_PATH "C:/Qt/6.1.2/")
if (MSVC)
    set(QT_PATH ${QT_PATH}msvc2019_64)
else ()
    set(QT_PATH ${QT_PATH}mingw81_64)
endif ()

This essentially " for now" set correct QT version for either MSVC or Mingw, In future I'll handle mac/arm/etc. But for now basics.

So what I end up is, mingw as my toolchain and QT from mingw folder using either qt-mingw bundled compiler or program files/official one. Both fail.

[Christian Ehrlicher]

I can only tell you what I see - you somewhere mixing up MinGW and MSVC - you're using a MinGW compiler but your Qt thinks it's MSVC.

[Dariusz]

@Christian-Ehrlicher Yeh, its... difficult. I think I don't know to "properly" set an explicit path to a specific qt version... what would be the cmake command for it ?

[VRonin]

@Dariusz said in Unable to compile using Mingwx64 on windows, Command line option error:

what would be the cmake command for it ?

There shouldn't be one. Do not set it in CMakeLists.txt

The idea is that find_package should be able to find it. There are 2 ways to do this:

• have the Qt path in your PATH
  • this is what you normally do on the command line, call qtenv2.bat from the Qt bin folder and it will set up your environment so that find_package will work
• add the Qt path to CMAKE_PREFIX_PATH
  • this is what Qt Creator does automatically when you configure the Kit

[Dariusz]

@VRonin said in Unable to compile using Mingwx64 on windows, Command line option error:

@Dariusz said in Unable to compile using Mingwx64 on windows, Command line option error:

what would be the cmake command for it ?

There shouldn't be one. Do not set it in CMakeLists.txt

The idea is that find_package should be able to find it. There are 2 ways to do this:

• have the Qt path in your PATH
  • this is what you normally do on the command line, call qtenv2.bat from the Qt bin folder and it will set up your environment so that find_package will work
• add the Qt path to CMAKE_PREFIX_PATH
  • this is what Qt Creator does automatically when you configure the Kit

I dont want path/environemnt based Qt library. I have many projects each of which require specific qt to be run on/tested on. The idea of having to edit path every time I change projects is quite... bad. So I need to set qt via code & copy dlls manually as far as I can tell.

The idea that there will be only 1 qt version on the system is quite... frustrating to me.

[VRonin]

@Dariusz said in Unable to compile using Mingwx64 on windows, Command line option error:

The idea that there will be only 1 qt version on the system is quite... frustrating to me.

There isn't. I have 4 versions on my machine (5.5, 5.15, 6.1, dev). I don't know CLion but I'm sure there is a way to set CMAKE_PREFIX_PATH before it runs CMake, see https://stackoverflow.com/questions/54444846/equivalent-of-cmake-prefix-path-in-clion
Set it to C:/Qt/6.1.2/mingw81_64 and remove the set(QT_PATH