Question

In fact I’m not really here for a question but to share an issue which drived me crazy during hours.

The classical solution for the error ‘expected unqualified-id […]’ in most of the cases is a missing semicolon at the end of your class declaration. That is not the case here.

Now let me explain what happened. I needed a class a some objects developped by a co-worker and those sources where already used by other part of the soft. So I know it’s working and usable. So I modified my makefile and my includes, recompile and boom, I have that:

foobar.hh:81: error: expected unqualified-id before “protected”

I was including pretty much the same things than my co-worker with similar makefile and environnement, so I couldn’t understand the issue. But finally, we found the big difference:
I’m using QT (since I’m developping a GUI) and the methods pointed by the compiler where the errors occured were all named ‘signals’.

I don’t have the full explanation, but we only changed the methods names to something else, and it’s working. For QT users, you know that signals is a specific QT word, used for the signal/slot mechanism, but I still lost a lot of time on that. If somebody can explain precisely the issue I’m interested, but I wanted to share this quick workaround with you (and because stackoverflow helped me by the past a loooot of time).

Regards,
Ikwy

Answer 1

signals is a kind keyword in Qt. This name can not be used as identifier in Qt. You cannot declare functions or variables with this name.

• You can just rename your identifier.
• Or you could make your project with Qt keywords disabled, but then you should make sure those keywords are not used in your project in their Qt meaning. (And they probably are). To disable keywords you should make your project (assuming using qmake) with CONFIG += no_keywords option enabled)