Pass signal to a function and emit it

federico.massimi

hi, I wanted to know if it was possible to pass a signal to a function, let me explain better:
it is possible to write such function in QT C++ (Pseudocode):

bool MyClass::test(int value, .... my_signal) {
      if( value > 0 ) {
              emit my_signal(value);
              return true;
      } else return false;
}

And call it in this way

test(value1, MyClass::my_signal_for_value1);
test(value2, MyClass::my_signal_for_value2);

Thanks in advance

jsulm

@federico-massimi You could pass a lambda which emits the signal instead of passing signal.

J.Hilk

@federico-massimi
since a signal is nothing but a function itself, you should be able to pass function pointers as arguments.

Like one does in c++ :)

take a look here for some hands on stuff
https://stackoverflow.com/a/12662961

VRonin

template <class T>
bool test(int value, T my_signal) {
    if( value > 0 ) {
        (this->*my_signal)(value);
        return true;
    }
    return false;
}

Usage myObject.test(value1, &MyClass::my_signal_for_value1);

JonB

@VRonin , @federico-massimi
I like @VRonin's template-based definition above. In addition, if I understand rightly(?), his use of (this->*my_signal)(value) means that your slot can still access QObject::sender(), which can be useful.