Question

I got a strange beaviour in my program.
I wrote a test which always failed.
While debugging i saw something i don’t understand:

I got some multiple Constructors, but this one gets always called if i pass unicode via _T():

IsNullable(bool isNullable)
    : m_bIsNullabe(isNullable), Flag(eNullAllowed)
{};

And here’s my way of calling the constructor:

... = new IsNullable(_T("N"));

The strange thing is that the bool Constructor above gets always called…
Why is that so? I would be really pleased if someone got a clue!

Greeds,
Clemens

EDIT:

This Constructor should get called:

IsNullable(wchar_t isNullable)
    : Flag(eNullAllowed)
{...};

Answer 1

The constructor that you want to be called takes a wchar_t character, not a pointer to a wide string. Call it as:

IsNullable( L'N' );

Note that I’m not using the _T macro because your constructor argument type is wchar_t and it is not predicated on whether the UNICODE symbol is defined. So there’s no need for that macro in this case.

The reason the other constructor is being called is because the string literal, of type const wchar_t[2] (assuming the _T macro expands to L"N"), decays to a const wchar_t * which is then implicitly converted to a bool.