Re: [Boost-users] [ptr_container] Why is the key passed to ptr_map by non-const reference?

From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2007-09-24 04:01:26

Boris skrev:
> Before anyone refers me to the FAQ at  
> http://www.boost.org/libs/ptr_container/doc/faq.html#why-does-ptr-map-t-insert-replace-take-two-arguments-the-key-and-the-pointer-instead-of-one-std-pair-and-why-is-the-key-passed-by-non-const-reference  
> - I read it. While it's clear why a reference is used I don't understand  
> why it is a *non-const* reference. Any reason why it's not const?

A temporary object can bind to a const reference, thus a call to a 
throwing constructor can be placed as the key argument.

-Thorsten