Re: [Boost-users] shared_ptr as reference argument

Subject: Re: [Boost-users] shared_ptr as reference argument
From: Emil Dotchevski (emildotchevski_at_[hidden])
Date: 2009-03-19 20:56:58

On Thu, Mar 19, 2009 at 4:29 PM, Ovanes Markarian
<om_boost_at_[hidden]> wrote:
> What about RVO and NRVO?
>
> You still can bind a temporary to a const reference. This is a simple
> example on how it is possible to do optimizations. Or am I mistaken?
>
> Example:
>
> std::string foo();
>
>
> void bar()
> {
>    std::string const& bound_temporary = foo();
>
>    std::cout << bound_temporary;
> }
>
> whereas this is invalid:
>
> void invalid_bar()
> {
>    std::string& bound_temporary = foo(); //will not work, but AFAIK some
> compilers support it
> }

Right, your first snippet is valid and the second is ill-formed.

> So compilers can do optimizations based on constness.

What optimizations do you have in mind? The second snippet is simply
illegal C++ (should not compile.)

Emil Dotchevski
Reverge Studios, Inc.
http://www.revergestudios.com/reblog/index.php?n=ReCode