C2059：语法错误：Qt中的'public'

Question

I was getting this error which was driving me crazy. I just added a class using Qt Creator but it will not build.

#ifndef LIBRARY_H
#define LIBRARY_H

class Library
{
public:
    Library();

signals:

public slots:
};

#endif // LIBRARY_H

The errors are:

library.h:12: error: C2059: syntax error : 'public'
library.h:12: error: C2334: unexpected token(s) preceding ':'; skipping apparent function body
library.h:13: error: C2760: syntax error : expected '{' not '}'
library.h:13: error: C2143: syntax error : missing '}' before ';'
library.cpp:4: error: C2535: 'Library::Library(void)' : member function already defined or declared
library.cpp:8: error: C1004: unexpected end-of-file found

Answer 1

The problem was Qt Creator added signal and slots even though I added a C++ class (as opposed to Qt class) and didn't derive it from QObject .

The solution is to remove signal and slots words from the class or derive it from QObject and #include <QObject>