Thread: non-redundant use of &*

Up until now I considered it redundant, but I've just recently needed to use &* legitimately and was wondering if there are any other cases for its use?

Code:

void doStuff( Foo* p ){ ... }
...
list<Foo> foos;
for( list<Foo>::iterator it = foos.begin(); it != foos.end(); ++it )
 doStuff( &*it );

You could try

Code:

void doStuff(/*const?*/ Foo& p);

However, an iterator is not a pointer, so "dereferencing" it and getting the address of the result doesn't give you the same thing back.

Originally Posted by anon

However, an iterator is not a pointer, so "dereferencing" it and getting the address of the result doesn't give you the same thing back.

I believe that's the point - otherwise &* would be redundant.

Originally Posted by Elysia

I believe that's the point - otherwise &* would be redundant.

Exactly. It is non-redundant because the iterator is not a pointer as such - it PRETENDS to be a pointer by having an operator*() that returns the address of the actual object represented by the iterator proxy object.

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Mats

Ah I see, I forgot about overloaded ref/deref operators. I guess that answers the question then: in C++ you can always define &* to be a non-redundant operation...

Indeed, but I wouldn't just about abuse it everywhere, because it breaks logic.
It could especially confuse C programmers, I suppose, but then again, what C programmer scourges through and maintains C++ code?

Originally Posted by Elysia

It could especially confuse C programmers, I suppose, but then again, what C programmer scourges through and maintains C++ code?

Judging by some of the code we have here that come from third parties: Far too many!

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Mats

It was also a sort of half-sarcastic joke.
I know there have been some C programmers who have maintained or read C++ code, which is actually why I added the meaning of precaution. Don't abuse &*.

Originally Posted by Elysia

It was also a sort of half-sarcastic joke.
I know there have been some C programmers who have maintained or read C++ code, which is actually why I added the meaning of precaution. Don't abuse &*.

Sure, I understood it as a joke, but I also look at it from my view - there are some people who are not using C++ like they should.

And abusing operators in general is something that should be done with care.

--
Mats

Originally Posted by Elysia

Indeed, but I wouldn't just about abuse it everywhere, because it breaks logic.
It could especially confuse C programmers, I suppose, but then again, what C programmer scourges through and maintains C++ code?

Actually, that's pretty much the reason for this thread! I'm primarily a C-programmer, and so immediately thought "&*" = redundant; until I was reminded of the shapeshifting abilities of overloading.