class with q_object macro declared and defined in .cpp

[user4592357]

i know that one can't have a nested class which has Q_OBJECT macro defined in it, in a class (even though i don't quite well understand the reasons, if someone explained i'd be very happy)

but my question here is about something else. as i can't have a nested (private) class, i'd like to place that clasa in .cpp file, as the title suggests, which i did and got "undefined reference for vtable" error, while my class had a virtual dtor (it's derived from QWidget). but when i place the class in .h file, it works fine. what's the reason for this?

[SGaist]

Hi,

You are missing the moc file inclusion at the bottom of the your code.

[mrjj]

The reason is:
The moc tool that uses the Q_OBJECT and generate mappings for signals and slot are run on .h files only.

[user4592357]

so how can i "hide" this class? it's something like this:

class A : public QWidget {/* definition */};

class B : public QWidget {
     A *a;
     // other members
     // other functions
};

of course i wanna "hide" class A

[mrjj]

@user4592357
Hi
You can use the .cpp file as @SGaist suggests.

more info
https://stackoverflow.com/questions/34928933/why-is-important-to-include-moc-file-at-end-of-a-qt-source-code-file