Re: [boost] Mini-proposal, simple boost/handle.hpp lib

From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2008-08-08 09:25:35

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On Friday 08 August 2008 09:02 am, Mathias Gaunard wrote:
> Frank Mori Hess wrote:
> >> boost::shared_ptr<int> s;
> >> {
> >>   int sockfd = socket(PF_INET,SOCK_STREAM,0);
> >>   if( sockfd!=-1 )
> >>     s.reset(&sockfd, boost::lambda::bind(close, * boost::lambda::_1));
> >> }
> >>
> >> I've never really used lambda, but it compiles at least.  By the way, is
> >> there any documentation on the lambda headers (which ones to include to
> >> use what)? I didn't see anything in the lambda docs.
> >
> > Err, nevermind.  This will fail when sockfd goes out of scope.
>
> boost::shared_ptr<void> s;
> {
>     int sockfd = socket(PF_INET, SOCK_STREAM, 0);
>     if( sockfd != -1)
>         s.reset(static_cast<void*>(sockfd), bind(close,
> static_cast_<int>(_1)));
> }

make_handle() Emil's handle.hpp creates a shared_ptr which points at a copy of 
the handle, whose lifetime is also controlled by the shared_ptr.  So, you can 
access the handle through the shared_ptr as well as having the shared_ptr 
call the handle's cleanup function in its deleter.  But my attempt at using 
lambda stores a pointer to the original handle in the shared_ptr, which 
becomes invalid as soon as the original handle goes out of scope.
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