Re: [Boost-users] enable_shared_from_this - or an alternative..

From: David Klein (d.klein_at_[hidden])
Date: 2006-03-20 05:27:17

boost-users-bounces_at_[hidden] wrote:
> Hello All,
> 
> I have a couple of classes that I want to self register themselves
> with a monitoring class. To do this they must pass a shared_ptr of
> themselves to the monitor register function.
> 
> Therefore I need to make a shared_ptr form the this pointer, in the
> constructor.
> 
> I have derived my classes from enabled_shared_from_this...(code to get
> monitor omitted)
> 
> //psuedo code..
> monitor::AddSource1(boost::shared_ptr<CSource1>);
> monitor::AddSource2(boost::shared_ptr<CSource2>);
> 
> class CSource1 : public enable_shared_from_this<CSource1>
> {
> 	CSource1() {  Monitor->AddSource(shared_from_this()); };
> }
> 
> and
> 
> class CSource2 : public base1, public
> enable_shared_from_this<CSource2> {
> 	CSource2() {  Monitor->AddSource(shared_from_this()); };}
> }
> 
> 
> This all compile fine, but when run, the shared_from_this call
> asserts with a bad weak ptr - at the time of calling the weak_ptr has
> no content, and looking at the boost code, I cannot see where it is
> supposed to get set to access the this value.
> 
> Should I be using enable_shared_from_this in this way or is there a
> better way to convert the this ptr to a shared_ptr in a constructor
> that I need to use.
> 
> 
> James
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users

hi james,

see: http://boost.org/libs/smart_ptr/sp_techniques.html#in_constructor

HTH dave