Re: non-const reference and const reference
Ben Voigt [C++ MVP] wrote:
"George" <George@discussions.microsoft.com> wrote in message
news:593CA7FA-6B65-452D-B2D1-7486F3435D14@microsoft.com...
Hello everyone,
This is my understanding of non-const reference, const reference and
their relationships with lvalue/rvalue. Please help to review
whether it is correct
and feel free to correct me. Thanks.
1. A const reference can be binded to a rvalue, for example, a
temporary object. And the "life" of the temporary object is
guaranteed to be extended
and we can safely operate through the const-reference.
No, the lifetime of the temporary object is only extended up to a
limit (the enclosing block), certain uses are not safe.
The limit you're talking about is the lifetime of the reference.
If I create a dynamic object with a member that is a reference to
T and initialise that reference with some temporary of type T,
and then I never delete that dynamic object, the temporary should
survive until the program ends (regardless of scopes, etc.)
Especially returning such a reference is not safe (as you posted in a
subsequent thread).
Returning a reference initialises another reference. Often the
actual event of initialising another variable or temporary is
missed by the programmer; the binding to a temporary established
at some point does not survive (and is not transferred by)
initialising some other, unrelated, reference.
Also using such a reference to bind a member reference in a
ctor-initialization-list is not safe.
Not sure what you mean by this, so no comment.
V
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