Basic question: Including headers with INCLUDEPATH doesn't work

mrjj

No, it works that way. pr default. Nothing I have seen in Creator adjust that.
Only thing that can go wrong is path is invalid ( on windows, spaces in path can be issue)

HEADERS += libA.h

Will work if the libA.h is in the same folder as the .pro file
Else its FALSE and will not work.

Binary91

@mrjj
I found out that the problem only appears to a few header files!

I include 3 headers, each declaring a subclass of a standard Qt class:

INCLUDEPATH += C:/Qt/lib/headers

HEADERS += main.h

SOURCES += main.cpp \
myQLineEdit.cpp \
myQPushButton.cpp \
myQString.cpp

The errors appear to the functions defined in the source files myQLineEdit.cpp and myQPushButton.cpp, but NOT in myQString.cpp!

I think I got the problem!! In myQLineEdit and myQPushButton class, I do have a Q_OBJECT. Can this cause the problems??

mrjj

Q_OBJECT is used by a tool called moc.exe to help make signals and slot possible
It should not to anything with regards to include files. :)
As far as I have ever seen.

Binary91

that is really annoying..
Why do those undefind reference errors appear to some of my source files but not to all of them?
Don't know where to search for an answer now

Binary91

By the way:
the problem really is Q_OBJECT...

I just wrote "Q_OBJECT" into the myQString class and look what happened: undefined reference vtable ... in myQString.cpp!

So Q_OBJECT makes the problems why I have to add all headers to the project! How can I avoid this?

mrjj

when u add Q_OBJECT, please run qmake!

Binary91

I already tried that.
Building, running
Building, qmake, running
qmake, running
qmake, building, running

None of the above ways succeded

mrjj

@Binary91
then please as last test
Complete delete the build folder.

Binary91

tried that, two.

Deleted everything but my project file and the sources/headers. Didn't work :-(

Is it possible that qmake ignores INCLUDEPATH?

mrjj

@Binary91
Well anything seems possible with your setup. :)
Q_OBJECT should not bork anything.

Im out of ideas :)

Binary91

Well, I'll post the whole project file, its headers and sources and maybe you can copy/paste it and try to run it with?

If it works, then it is a setting problem. If not, something with my include logic doesn't work.

project file:

#-------------------------------------------------
#
# Project created by QtCreator 2016-11-17T15:45:17
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = CourseCalculator
TEMPLATE = app

INCLUDEPATH += C:/Qt/lib/headers

HEADERS  += main.h

SOURCES += main.cpp
           C:/Qt/lib/sources/myQString.cpp \
           C:/Qt/lib/sources/myQLineEdit.cpp \
           C:/Qt/lib/sources/myQPushButton.cpp

main.cpp:

// main.cpp

#include "main.h"

int main(int argc, char *argv[])
{
  QApplication applicationApp(argc, argv);
  clsWindowMain windowMain;

  QTimer::singleShot(0, &windowMain, SLOT(slotStart()));
  int ret = applicationApp.exec();
  return ret;
}

main.h:

// main.h

#ifndef MAIN_H
#define MAIN_H

#include <QApplication>
#include <QTimer>
#include <QWidget>
#include <QDialog>

#endif // MAIN_H

myQLineEdit.h:

// myQLineEdit.h

#ifndef MYQLINEEDIT_H
#define MYQLINEEDIT_H

#include <QDebug>
#include <QLineEdit>
#include <QMessageBox>
#include <QDir>


// forward declaration

class myQLineEdit;


// declaration

class myQLineEdit : public QLineEdit
{
  Q_OBJECT

  // .. properties

  public:
    myQLineEdit(QWidget* widgetParent = 0);
    ~myQLineEdit();

    // .. more methods
};

#endif

myQLineEdit.cpp:

// myQLineEdit.cpp

#include <myQLineEdit.h> // absolute path or absolute path with whitespaces also doesn't work


// ----- constructors -----

myQLineEdit::myQLineEdit(QWidget* widgetParent) : QLineEdit(widgetParent)
{
   // stuff
}

Is that compilable for you?

mrjj

@Binary91
would be very much easier if you zipped folder and shared via dropbox or g drive as
copy paste to real files again is very error prone and time consuming :)

Binary91

Good idea. But my dropbox accout has no free memory left :-D

Have to create a new account first, maybe on g drive...

mrjj

@Binary91
well a zipped project is ultra small. so delete/remove something for a moment and it should have space :)

btw: G Drive is 15 GB but the client is nowhere near as nice as dropbox.

jsulm

@Binary91 If you derive from Qt classes which are derived from QObject then you need to include the generated moc_ files.
For example in myQLineEdit.cpp add

#include "moc_myQLineEdit.cpp"

Binary91

but from where do I get this moc file?
If I try to include, compiler gives me an error that it can not find such file or directory

btw:
https://www.dropbox.com/s/whqdkcat767224t/test.zip?dl=0

jsulm

@Binary91 You should read the Qt documentation. The moc_ files are generated for you using moc tool. Take a look at the build directory.

jsulm

@Binary91 Why do you have a main.h? This is quite unusual.

jsulm

@Binary91 For QApplication you need QT += gui, else you should use QCoreApplication.

Buckwheat

@jsulm , why would you include the MOC files? I "never" include the MOC files in my source because they get generated, compiled, and linked after the normal build. The only generated file I would include is the ui_NameOfForm.h file created when using the form designer. And, only in the CPP for the UI class.

@Binary91 , I am sure it was explained that INCLUDEPATH tells qmake where to find common include files. I use it for 3rd party libraries or pre-built packages I developed for Qt (I treat them like 3rd party libraries). And, as I know you know... always run qmake after changing a PRO file.

There is one curious item I have found about QtCreator though... if you are using static libraries (even if your dependencies are setup) and make a change to a CPP file in the library... Press build-all and it will build the library and NOT re-link the application or shared library that depends on that static library. Kind of annoying but I just get around it!