explicit operator bool error

问题

I get the Compiler Error C2071 when I try to implement the explicit operator bool:

class C
{
public:

    explicit operator bool() const
    {
        return !!*this;
    }
};

Why? How can I solve this problem?
I'm using Visual Studio 2012 RC.

回答1:

Visual Studio 2012 does not support explicit conversion operators, see C++11 Features in Visual C++ 11.

These articles talk about the safe bool idiom:

• http://www.artima.com/cppsource/safebool.html
• http://en.wikibooks.org/wiki/More_C++_Idioms/Safe_bool

回答2:

If you look at a list of features in Visual Studio 2010 you can see that it was not an available feature. A look at What's New for Visual C++ in Visual Studio 2012 shows that is has not been added.

来源：https://stackoverflow.com/questions/11365129/explicit-operator-bool-error