Meryl Silverburgh wrote:

On 5/8/07, Nat Goodspeed <ngoodspeed@solidworks.com> wrote:

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-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users- bounces@lists.boost.org] On Behalf Of Meryl Silverburgh Sent: Tuesday, May 08, 2007 9:32 AM To: boost-users@lists.boost.org Subject: [Boost-users] Pointer in function parameter?

vector< boost::shared_ptr<A> > aVector;

aFunc(aVector[0]) ; // just call a

My question is should I change the function parameter of aFuncion from this:

void aFunc(A* aPtr) { // access aPtr }

to this:

void aFunc(shared_ptr<A> aPtr) { // access aPtr }

[Nat] Looks reasonable to me... I believe the docs say that it's conventional to pass shared_ptr by value rather than (e.g.) const reference so that the ref count will be adjusted properly.

Thanks. But what if I have

void aFunc(const A* aPtr) { // access aPtr }

should I change it to

void aFunc(const shared_ptr<A> aPtr) { // access aPtr } Hi,

I would say: Yes, you should change it to the 2nd variant, BUT sometimes the first variant is also ok. You could use the 1st variant, but you will loose your benefit from shared_ptr<>. You have to gurantee that the shared_ptr<> is not destroyed while you are running aFunc(). So use the 2nd variant and choose the safe way. I hope it is a little more clear to you now! Much fun Manuel Jung

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On 5/8/07, Nat Goodspeed <ngoodspeed@solidworks.com> wrote:

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-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users- bounces@lists.boost.org] On Behalf Of Meryl Silverburgh Sent: Tuesday, May 08, 2007 10:41 AM To: boost-users@lists.boost.org Subject: Re: [Boost-users] Pointer in function parameter?

But what if I have

void aFunc(const A* aPtr) { // access aPtr }

should I change it to

void aFunc(const shared_ptr<A> aPtr) { // access aPtr }

[Nat] 'const A*' is "pointer to const A".

'const shared_ptr<A>' is "const shared_ptr to non-const A".

You probably want 'shared_ptr<const A>'.

Thanks for all the help. So is it safe to say I can replace all 'A*' in my program to shared_ptr<A>? I don't need to worry about scoped_ptr or other smart pointers in boost?

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-----Original Message----- From: boost-users-bounces@lists.boost.org [mailto:boost-users- bounces@lists.boost.org] On Behalf Of Meryl Silverburgh Sent: Tuesday, May 08, 2007 11:32 AM To: boost-users@lists.boost.org Subject: Re: [Boost-users] Pointer in function parameter?

So is it safe to say I can replace all 'A*' in my program to shared_ptr<A>?

[Nat] As long as all your A objects are allocated on the heap, yes.

I don't need to worry about scoped_ptr or other smart pointers in boost?

[Nat] We don't. The only other Boost smart pointer we've used is intrusive_ptr, and that only because we learned a bit late about the shared_ptr mechanism for returning a new shared_ptr to 'this'. Also, with respect to some of the other Boost libraries (notably Boost.Python), shared_ptr is "smarter" than the other Boost smart pointers.