As an aside, this came about because the initial reaction was to do the following, which is REALLY bad

vector<Foo>::iterator iter = find( myFoo.begin(), myFoo.end(), shard_ptr(this) );

It compiles just fine, then quickly crashes when it leaves scope and deletes this.

having a shared_ptr of *this* is a unrelated issue (in my view a big no-no). you can find some info here: http://www.boost.org/libs/smart_ptr/enable_shared_from_this.html

At Friday 2004-09-17 13:05, you wrote:

At 9:18 PM +0200 9/17/04, Vukasin Toroman wrote:

...

...

As an aside, this came about because the initial reaction was to do the following, which is REALLY bad

vector<Foo>::iterator iter = find( myFoo.begin(), myFoo.end(), shard_ptr(this) );

It compiles just fine, then quickly crashes when it leaves scope and deletes this.

having a shared_ptr of *this* is a unrelated issue (in my view a big no-no). you can find some info here:

http://www.boost.org/libs/smart_ptr/enable_shared_from_this.html

I don't want a shared_ptr to this because it is a big no-no as you point out. What I want is the ability to automatically compare the shared_ptr<T> to a T *.

I believe a "T const*" would be more appropriate

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At 1:40 PM +0300 9/20/04, Peter Dimov wrote:

Michael Rutman wrote:

...

I'd like to propose adding a template function to shared_ptr to allow the automatic testing of a shared_ptr to its raw ptr.

The template is as simple as

template <class T> bool operator==(boost::shared_ptr<T> const & a, T * const & b) { return a.get() == b; }

Here is the case where I need it.

I have a vector<Foo> myFoo.

In a method of Foo I need to see if this instance is in the vector. I want to do this

vector<Foo>::iterator iter = find( myFoo.begin(), myFoo.end(), this );

This is a reasonable suggestion. It turns out that std::find _is_ specified in a way that allows heterogeneous comparisons, although this may be an oversight on the part of the committee and not a design decision. ;-)

I just found out that on gcc 2.96 it also needs the following template <class T> bool operator!=(boost::shared_ptr<T> const & a, T * const & b) { return a.get() != b; } gcc 3.3 works fine without this template but the earlier gcc needs both. I'm not sure how that effects the proposal. Peter, I see that you are the maintainer of shared_ptr. Is there any chance you'll add this for the next release of boost? Thanks

At 3:36 PM +0300 9/21/04, Peter Dimov wrote:

Michael Rutman wrote:

...

Peter,

I see that you are the maintainer of shared_ptr. Is there any chance you'll add this for the next release of boost?

No, it's too late for 1.32 now, sorry.

How about for 1.33?