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From: Rush Manbert (rush_at_[hidden])
Date: 2006-05-10 18:30:08

I have a template class that is designed to contain built in types or
std::string types. I always need to be able to cast an instance of the
class as a std::string, and I also need to be able to cast it as the
parameter type with which it was instantiated.

In my class definition, I have defined two cast operators, like so:
(Extraneous stuff omitted)

template<typename T>
class MyDataObject : public MyDataObjectBase

        // Cast as std::string
        inline operator const std::string & ()
                                        ...some code here
        // Cast as T
        inline operator const T & ()
                                        ...some code here

The original code was written on a Mac and compiled with Gnu, which did
not complain. even when I did this:

class MyStringObjectClass : public MyDataObject<std::string>

Now, however, I have moved the code to Windows, and the Visual Studio
compiler complains about the second cast operator when I define

I thought that if I could conditionally define the cast as T operator
(or the cast as std::string) I would be okay, but that means testing
against the value of T with the preprocessor. I don't see how to do
that, but I know that some of you folks are really good at bending the
preprocessor to your will.

Can anyone show me a way out of this predicament?


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