[Insight-users] What's # in "#thisClass"?

[David Gobbi]

Hi Yuanixin,

The "#" is part of the magic of the C preprocessor.
If you have #thisClass inside the body of the macro,
then the preprocessor puts quotation marks around
the value that "thisClass" expands to.

So   itkTypeMacro(MyClass)

results in

     { return "MyClass";}

For more information, look for "preprocessing" in the index
of your C++ book.

Cheers,
 - David



On Wed, 14 Jul 2004, Yuanxin Zhu wrote:

> Hi there,
>
> I'm new to ITK and haven't touch C++ for quite a few years. While I read
> itkMacro.h, I found the following statement for itkTypeMacro():
>
> #define itkTypeMacro(thisClass,superclass) \
>     virtual const char *GetNameOfClass() const \
>         {return #thisClass;}
>
> My question is what the "#" in front of "thisClass" stands for. My guess
> is that it should be an operator to get the type of a class. But I can
> NOT even spot it in "The C++ Programming Language (3rd Ed.)". Is the book
> is too old to be a C++ reference?
>
> Anyone has a clue?
>
> Thank you in advance.
>
> Yuanxin
>
>
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