From: Peter Dimov (pdimov_at_[hidden])
Date: 2004-10-16 08:10:27
John Torjo wrote:
> Peter Dimov wrote:
>> John Torjo wrote:
>>> Hi Peter,
>>> Just a thought: perhaps this constructor:
>>> explicit shared_ptr(weak_ptr<Y> const & r);
>>> should be private,
>>> and the only way to create a shared_ptr from a weak_ptr is:
>>> shared_ptr<T> val = weak->lock();
>>> This way, the shared_ptr public constructors will never throw. Users
>>> will not make mistakes like this:
>>> shared_ptr<T> val = weak;
>> This shouldn't compile on a reasonably compliant compiler, because
>> the constructor is explicit.
> True, sorry, I meant this:
> shared_ptr<T> val(weak);
> The point still remains.
I'm not sure that it does. The canonical way to work with a weak_ptr is
if( shared_ptr<T> p = weak.lock() )
// do things with *p
You can't accidentally omit the lock(), and shared_ptr<T> p( weak ) is
invalid in an if statement.
shared_ptr<T> val( weak ); does exactly what it is intended to do.
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk