creating subfolders causes QML build issue

[mzimmers]

Hi all -

My project has gotten large enough to merit breaking the code into subfolders. I took the following steps:

• created a subfolder ("equipment")
• moved two files into that subfolder
• changed the reference in CMakeLists.txt to reflect that move
  When I build, I get an error, reported on a file in my build folder. The file is <myProjectName>_qmltyperegistrations.cpp, and the error is on this line:

/****************************************************************************
** Generated QML type registration code
**
** WARNING! All changes made in this file will be lost!
*****************************************************************************/

#include <QtQml/qqml.h>
#include <QtQml/qqmlmoduleregistration.h>

#include <activity.h>
#include <activitymodel.h>
#include <equipment.h>  // <== THIS LINE

Which is a correct error message, but leaves me wondering how to deal with it. How does this file get generated?

Thanks...

[Mesrine]

@mzimmers You can do it as Christian says, with the library. If you do not want the library do not add a CMakelists.tx in the subfolder. Just reference the sources from the root CMakelists.txt like subfolder/equipment.cpp ...

[mzimmers]

I've tried converting the contents of my subfolder to a library, to see if that will work for me, even though it really isn't necessary.

A header file in my subfolder includes a header file from the main folder. I added aline to the subfolder CMakeLists.txt file:

target_include_directories(equipment PRIVATE
    "."
    ".." // <== this line added.
)

but, the included header contains an extern reference. At build time, I'm getting this error now:

:-1: error: equipment/CMakeFiles/equipment.dir/equipment.cpp.obj:equipment.cpp:(.rdata$.refptr.INVALID_TEMP[.refptr.INVALID_TEMP]+0x0): undefined reference to `INVALID_TEMP'

(INVALID_TEMP is the extern reference in the header file.)

Any suggestions on how to fix this? Thanks...

[Mesrine]

@mzimmers
I recommend showing us some Cmakelists.txt, project structure, and some headers.
But I think, your problem is related to C++ project structure.

[mzimmers]

@Mesrine project structure is simple: I have a top-level directory and two subfolders for QML. I'm trying to add a subfolder for C++ code.

here's a portion of the subfolder's CMakeLists.txt file:

cmake_minimum_required(VERSION 3.16)
project(equipment)
qt_add_library(equipment
    equipment.cpp equipment.h
)

set_target_properties(equipment PROPERTIES
    WIN32_EXECUTABLE TRUE
)

target_include_directories(equipment PRIVATE
    "."
    ".."
)

equipment.h has this line:

#include "constants.h"

which can be found in the main folder. It has this line:

extern const float INVALID_TEMP;

Which is defined in constants.cpp.

[Christian Ehrlicher]

@mzimmers said in creating subfolders causes QML build issue:

Which is defined in constants.cpp.

Don't you think this source file shouldn't be compiled into the library then?

[mzimmers]

@Christian-Ehrlicher aargh...yes, I suppose so.

I really didn't want to make a library anyway - the purpose of the subfolder was just to break up the main folder into smaller pieces. Oddly enough, I can't seem to find any documentation on how to do that.

[Mesrine]

@mzimmers You can do it as Christian says, with the library. If you do not want the library do not add a CMakelists.tx in the subfolder. Just reference the sources from the root CMakelists.txt like subfolder/equipment.cpp ...

[mzimmers]

@Mesrine yes, I think this is the best way to go for this app.

1. explicitly reference the subdirectories in the qt_add_executable() command.
2. do NOT use add_subdirectory() for this subdirectory.
3. do NOT use a CMakeLists.txt file in the subdirectory.
4. add this line to my target_include_directories() command:

    "${PROJECT_SOURCE_DIR}/equipment"

Seems to work.

Thanks to all for the help.

[Alex777]

This doesn't look good. The Qt's moc compiler can deal with source files located in the subfolders, and it even has -p, -f, -b files for fine grain controle. Then in the generated moc_MyClass.cpp it will put #include <subfolder/MyClass.h>
The qml module generator is less flexible though, and always generates #include <MyClass.h> which means I have to add subfolder to the target_include_directories. But this is not nice, because I like to have folder structure and having subfolder names in include directive increases readability.

[SGaist]

@Alex777 hi,

That's something you should check the bug report system for and maybe open a discussion.