Why when i build the project at that time why compiler gives error ?

JonB

@jsulm @Qt-embedded-developer , @jsulm, @SGaist

Unable to generate output for: /home/host/HOST/TWS_11_02_2024/14FEB2024/build-UiDirectoryStructure-Desktop_Qt_5_15_2_GCC_64bit-Debug/Makefile [TEMPLATE SUBDIRS]

TEMPLATE = SUBDIRS

Setup SUBDIRS template failed in QtCreator from 10 years ago (good Qt answers never fade!):

It should be TEMPLATE = subdirs, not SUBDIR

Use TEMPLATE = subdirs instead of TEMPLATE = SUBDIRS, i.e. not upper case letters..

:)

Qt embedded developer

@JonB said in Why when i build the project at that time why compiler gives error ?:

@jsulm, @SGaist

when now i am run this complete project i am getting below errors

On the issue tab it give the below error:

:-1: error: /usr/lib/gcc/x86_64-redhat-linux/13/../../../../lib64/crt1.o: in function `_start':

(.text+0x1b):-1: error: undefined reference to `main'

:-1: error: collect2: error: ld returned 1 exit status

:-1: error: [Makefile:253: Components] Error 1

Compiler gives the below errors:

/usr/bin/ld: /usr/lib/gcc/x86_64-redhat-linux/13/../../../../lib64/crt1.o: in function _start': (.text+0x1b): undefined reference to main'
collect2: error: ld returned 1 exit status
make[1]: Leaving directory '/home/host/HOST/TWS_11_02_2024/14FEB2024/build-UiDirectoryStructure-Desktop_Qt_5_15_2_GCC_64bit-Debug/Components'
make[1]: *** [Makefile:253: Components] Error 1
make: *** [Makefile:73: sub-Components-make_first] Error 2
14:54:56: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project UiDirectoryStructure (kit: Desktop Qt 5.15.2 GCC 64bit)
When executing step "Make"

I want to become expert of creating any type of project structure. So can anybody guide how i should start ?

@jsulm, @SGaist @JonB Thank you for several time contribution in several post of mine

JonB

@Qt-embedded-developer
The system's lib64/crt1.o is the entry point when your program is started. That will call its _start() function, and that in turn will expect to call your program's main(). But the error message says it cannot find any such main(). Which implies your linker command does not include your main program.

I have never used a subdirs project, sounds like that is not correctly picking up your main program. You could show the complete linker command (Compile Output pane, the last line where it does the linking). Probably needs someone who knows how subdirs project is supposed to work....

Qt embedded developer

@JonB Hi My compiler out put is :

cd Components/ && ( test -e Makefile || /home/host/Qt5.15.2/5.15.2/gcc_64/bin/qmake -o Makefile /home/host/P_host/TWS_11_02_2024/14FEB2024/UiDirectoryStructure/Components/Components.pro -spec linux-g++ CONFIG+=debug CONFIG+=qml_debug ) && /usr/bin/make -f Makefile
make[1]: Entering directory '/home/host/P_host/TWS_11_02_2024/14FEB2024/build-UiDirectoryStructure-Desktop_Qt_5_15_2_GCC_64bit-Debug/Components'
g++ -o Components MainApplication.o QmlEngineUtility.o moc_MainApplication.o moc_QmlEngineUtility.o /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Quick.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Widgets.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Gui.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5QmlModels.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Qml.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5WebSockets.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Network.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Core.so -lGL -lpthread
/usr/bin/ld: /usr/lib/gcc/x86_64-redhat-linux/13/../../../../lib64/crt1.o: in function _start': (.text+0x1b): undefined reference to main'
collect2: error: ld returned 1 exit status
make[1]: Leaving directory '/home/host/P_host/TWS_11_02_2024/14FEB2024/build-UiDirectoryStructure-Desktop_Qt_5_15_2_GCC_64bit-Debug/Components'
make[1]: *** [Makefile:253: Components] Error 1
make: *** [Makefile:73: sub-Components-make_first] Error 2
16:27:37: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project UiDirectoryStructure (kit: Desktop Qt 5.15.2 GCC 64bit)
When executing step "Make"
16:27:37: Elapsed time: 00:00.

I can able to see that my app folder's main.cpp not included when below command :

g++ -o Components MainApplication.o QmlEngineUtility.o moc_MainApplication.o moc_QmlEngineUtility.o /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Quick.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Widgets.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Gui.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5QmlModels.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Qml.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5WebSockets.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Network.so /home/host/Qt5.15.2/5.15.2/gcc_64/lib/libQt5Core.so -lGL -lpthread

try to build. but i don't know how to allow my main.cpp also. why it automatically not get taken. becuase my main is in main.cpp

i have created my source code such that the except main.cpp of App project is in Component project. so when i need to write unittest then it help. and as well as i want to link my component connect with app project using static library.

So what changes i need to do ?

JonB

@Qt-embedded-developer said in Why when i build the project at that time why compiler gives error ?:

try to build. but i don't know how to allow my main.cpp also. why it automatically not get taken. becuase my main is in main.cpp

And that is your problem. Like I said, I have never used a subdirs project. But I imagine that has some "main" project, which has your main.cpp in it. Are you building that top-level, main project, or are you perhaps only building one of the subprojects, which will not have a main?

Qt embedded developer

@JonB I am right clicking on active project name and then i am building it.

I have shared the main.pro file in main question. where i have added two sub project app and components.

SGaist

Share your other .pro files so we can see what is going on.

Qt embedded developer

@SGaist

TEMPLATE = subdirs

SUBDIRS += \
    App \
    Components

# Specify dependencies
App.depends = Components

The first sub dir project App's content is

    #########################################################################
    # Define project specific QT settings
    TEMPLATE = app

    TARGET = App

    QT          += qml
    QT          += quick
    QT          += core
    QT          += widgets
    QT          += websockets

    CONFIG      += c++17


    DEFINES += QT_DEPRECATED_WARNINGS


    DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000


    RESOURCES += \
        Gui/qml.qrc

    QML_IMPORT_PATH += $$PWD/Gui/

    SOURCES += \
        Main.cpp

    INCLUDEPATH += $$PWD/../Components
    INCLUDEPATH += $$PWD/../Components/Utility

    DEPENDPATH += $$PWD/../Components

And the second subdir project content is

```

TEMPLATE = app
QT += quick
QT += core
QT += websockets
QT += widgets

CONFIG      += c++17
CONFIG      += staticlib

DEFINES += QT_DEPRECATED_WARNINGS


DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

HEADERS += \
    MainApplication.h \
    Utility/QmlEngineUtility.h

SOURCES += \
    MainApplication.cpp \
    Utility/QmlEngineUtility.cpp

Anonymous_Banned275

@Qt-embedded-developer Can you build / compile each project by itself? Furthermore - are you sure you want TWO app(s) in project ?

ChrisW67

@Qt-embedded-developer I do not understand your second subproject PRO file. It uses
TEMPLATE = app
and simultaneously
CONFIG += staticlib

The CONFIG option staticlib means,

The target is a static library (lib only). The proper compiler flags will automatically be added to the project.

The target is either an application or a library, not both.