Re: [ROOT] easy histogram disabling

Dear Philippe, Axel,

many thanks for your comments and suggestions!

On 06/27/2011 06:39 PM, Philippe Canal wrote:
> For better or worse, this is not (and can not be) valid C++ code. In
> order to make the call to the Fill function (in particular because
> it is a virtual function), C++ requires dereference the pointer
> _before_ calling the function (because without this dereferencing it
> has _no_ way of knowing which function to call).

Thank you for pointing that out.  I have used code like

MyObject::Bla() {
   if (!this) return;
   ...
}

before, but I guess it only worked back then, because the Bla() wasn't 
virtual.

I've settled now for a variant using macros:

#define DRAW(H, ...) do { if (H) H->Draw(__VA_ARGS__); } while (0)
#define FILL(H, ...) do { if (H) H->Fill(__VA_ARGS__); } while (0)

Kind regards,
Thiemo

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