Question

Coming from a C# background, I have some habbits that need to be changed. I’m tring to return a QList<int> from a function. The compiler error message is conversion from ‘QList*’ to non-scalar type ‘QList’ requested. Here is the function:

QList<int> toCategories(QVariant qv)
{
    QList<int>categories = new QList<int>();
    if(qv.isValid() && qv.type() == QVariant::List)
    {
        foreach(QVariant category,qv.toList()){
            categories.append(category.toInt() );
        }
    }
    return categories;
}

I’d appreciate a link to the documentation or a function using the correct syntax

Answer 1

The error is referring to the fact that you are attempting to covert between a non-pointer QList to a pointer to a QList. You need to either use a pointer to a QList as follows:

QList<int>* toCategories(QVariant qv)
{
    QList<int>* categories = new QList<int>();
    if(qv.isValid() && qv.type() == QVariant::List)
    {
        foreach(QVariant category,qv.toList()){
            categories->append(category.toInt() );
        }
        return categories;
    }
}

Alternately, you can use a non-pointer QList:

QList<int> toCategories(QVariant qv)
{
    QList<int> categories;
    if(qv.isValid() && qv.type() == QVariant::List)
    {
        foreach(QVariant category,qv.toList()){
            categories.append(category.toInt() );
        }
        return categories;
    }
}

Since you are new to C++, I would recommend reviewing this question.

If I may also point out, your function as listed has a problem where a certain path doesn’t return a value (though I suspect that might be because you only copy-pasted a portion of your code).