Overloaded parenthesis operator

I'm using the EasyBMP library. I have a function that returns a BMP* object. BMP objects have the parenthesis overloaded, where I can do:

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BMP image;
*image(x,y)->Red=0;

But now that I'm trying to return a pointer, I want to do:

BMP *image;
*image(x,y)->Red=0;

but I get an error saying that image cannot be used as a function. How do I fix this?

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BMP* image = getimageptr();
*(*image)(x,y)->Red=0;

Or, perhaps better:

BMP* image_ptr = getimageptr();
BMP& image = *image_ptr;
*image(x,y)->Red=0;

(BTW, do you really dereference that object returned by op() before dereferencing it again to access Red? Seems odd!)

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The problem is that in the second example, image is of type BMP*, not BMP; since operator() is overloaded on BMP, you need to dereference the pointer before you use the call operator.

Hence, I think you will need to use:

*(*image)(x,y)->Red = 0;

I'm away from a compiler right now, so you'll have to forgive me if I messed up.

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Please read through the C++ FAQ #13.10. This FAQ item discusses overloading operator() for use with matrices. I believe this is what you want to do.

The FAQ also shows how to use the operator as well.