Question

I am writing a managed wrapper in C++/CLI (VS2010) for a third-party unmanaged library. In the code, I have a method that looks like this:

if(oldState != _state && UnitStateChanged != nullptr)
    UnitStateChanged(this, gcnew UnitStateChangedEventArgs(oldState, _state));

The “nullptr” generates the following error:

error C2446: ‘!=’ : no conversion from ‘int’ to ‘UnitStateChangedEventHandler ^’

The compiler seems to treat any use of “nullptr” as an “int”, even on something as simple as this:

Object^ temp = nullptr;

Everything i’ve read indicates that the compiler will figure it out on it’s own, but that doesn’t seem to be the case. Is there a setting that I’m missing (other than /clr or #pragma managed)?

Answer 1

Someone without a C++11 compiler wrote

#define nullptr (0)

somewhere in a header file?

(The usual macro is #define NULL (0))

---

This is, of course, forbidden.