Linking libs on moved project from Win/VS 2022 to RaspbianOS/QtCreator

Jacobotto

Hi all,

So I'm trying to move my project that includes some Qt libraries and also external one.
In VS I'm doing it like that in project's properties:
In C/C++->General->Additional Include Directories you must set the Qt installation include path;
In Linker->General->Additional Library Directories you must add the path of .libs files of your qt installation;
In Linker->Input->Additional Dependencies you must put the name of .lib files that you need in order to build the project.

In QtCreator on RaspbianOS I have mostly issue with QtNetwork libraries for now when debugging, as I'm getting e.g. "undefined reference to 'QNetworkAccessManager (...)"

When moving I've just created the new Qt console project, copied my code and filled .pro file. I'm including in main.cpp like this:

#include <QtNetwork/QNetworkAccessManager>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkReply>
#include <nlohmann/json.hpp>

..and this is what I've added to .pro file:

INCLUDEPATH += /home/jakub/Downloads/json-develop/include
INCLUDEPATH += /usr/include/i386-linux-gnu/qt5

What did i miss?

Chris Kawa

You need to add the network module to your qmake project. In the .pro file there's a QT += line. Add network there and re-run qmake (from the Build menu). qmake will then add the necessary paths and libs to your build config.

If you look at the documentation for Qt classes there's always information near the top what module you need for given class e.g. QT += network for QNetworkAccessManager

Jacobotto

@Chris-Kawa It solved the issue, thank you very much!

Jacobotto

Sorry for writing here again, didn't want to start new topic. I've noticed that deleting/commenting std libraries changes nothing. I mean the program can be rebuild and normally works, e.g. removing #include <string> when I'm using lot of std::string variables is completely fine. How it happens, what part of code includes them?

Chris Kawa

It most probably gets included transitionally by some other headers. Most compilers have a switch to print out include hierarchy for compiled files, so you can use it and search for /string or /string.h in the compilation output pane.
For MSVC you would add QMAKE_CXXFLAGS += /showIncludes in the .pro file. GCC has similar QMAKE_CXXFLAGS += -H option.