OK I did it. As I assumed the third party librarie has a deep impact of the QDebug-Infrastructure and catches all messages after the first time the library is used.

There was no need to configure in QtCreator or something else except in the config of these other libraries. Now I get the messages back in the IDE Application Output.

I hope that will help other poeple finding debugging problems.

A library is not an application. If you are targeting several Linux distributions, the nicest would be to provide a package using their format e.g. .deb files for Debian based distributions.

As for Windows, there's no real package format. Maybe using something like conan.io might be an option. Otherwise an archive that provides your .dll, header and .lib files for the various compilers you want to support is usually good enough.

However packing a full version of all your dependencies, while it sounds nice, might prove problematic. If you provide them, then you should also take care of updating them in case of security issues found during the year.

@douglas Take a look at http://doc.qt.io/qt-5/linux-deployment.html
And the question is: which version do you actually want to use?

I found the solution, when I realized that the debugger took 3 x F11 (step into) before moving to the next line. What was missing was a reference to the Qt source files. Solution :

Select Projects tool in QtCreator Select Manage Kits... Select Debugger in Popup Dialog Look for "Add Qt sources..." button Provide the path for the Qt source folder This path will be added as "Target Path" That's all - it works now...