Re: Newbie shared_ptr in a container question.

From: David Abrahams (dave_at_[hidden])
Date: 2003-07-26 20:48:35

Paul Grenyer <pjgrenyer_at_[hidden]> writes:

> On Sat, 2003-07-26 at 20:57, Joshua wrote:
>
> Hi
>
>> typedef std::vector<boost::shared_ptr<Foo> > FooVector;
>> 
>> FooVector Foobar;
>> Foo* blah = new Foo();
>> boost::shared_ptr<Foo> * NewPointer = new boost::shared_ptr<Foo>(blah);
>> Foobar.insert(*NewPointer); //Yes I know this looks horrible. And its probably wrong. 
>
> The above isn't quite right. You're inserting pointers to shared_ptr's.
> Try this instead:
>
> typedef std::vector<boost::shared_ptr<Foo> > FooVector;
> FooVector Foobar;
> Foobar.push_back( new Foo(blah) );

That won't work either; shared_ptr's constructor is explicit.  

you could write

    Foobar.push_back(boost::shared_ptr<Foo>(new Foo(blah)))

But Peter Dimov's excellent advice is "manage every newly-allocated
resource immediately with a *named* resource manager object"
(e.g. shared_ptr), leading to:

    boost::shared_ptr<Foo> myfoo(new Foo(blah));
    Foobar.push_back(myfoo);

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com