Re: [luabind] Preventing garbage collection of objects created with Luabind

[Greg S. <the...@gm...>]

Actually disregard my last post!! The problem is solved, thanks to all your
help. I discovered I don't need to use my GetPtr() function anymore (GetPtr
was updated to return the ComponentPtr smart pointer type).

When I was doing this I had the problem:

> c:push_back(Relay():GetPtr())

I discovered I no longer needed to use GetPtr() (lua is happy with what
Relay() provides, for whatever magical reason that I would like to
investigate):

> c:push_back(Relay())

Now I can call this all day long, without it being destroyed:

> print(c:at(0):Speak())
Relay

And when my app closes, the smart pointer deletes all remaining Component
instances.

Thanks again!

Greg


On Thu, Feb 25, 2010 at 3:58 PM, Greg Santucci <the...@gm...>wrote:

>
> Thank you. I tried incorporating boost shared pointers the way you
> describe, but when lua garbage collects, its still deleting the components.
> (I confirmed that the Relay destructor was being called through some
> shared_ptr boost code.) Is there a step I've missed which would have bumped
> up the use count?
>
>
> On Thu, Feb 25, 2010 at 1:49 PM, Nigel Atkinson <ni...@at...>wrote:
>
>> I third the smart pointer option.  I use them extensively throughout my
>> code both when dealing with Lua and in general.
>>
>> So you would have something like (typedefs just make it pretty):
>>
>> class Component;
>> typedef boost::shared_ptr<Component> ComponentPtr;
>> typedef std::vector<ComponentPtr> ComponentSet;
>>
>> etc;
>>
>> You bind this like:
>>
>> class_<ComponentSet>( "ComponentSet" )
>> // rest it like you did before....
>>
>> class_<Component, ComponetPtr>( "Component" )
>> // as before...
>>
>> and the tricky one...
>>
>> class_<Relay, Component, ComponentPtr>( "Relay" )
>> // Note that it uses the shared pointer type of the base.
>>
>> Of course if you are new to smart pointers, you will want to do some
>> reading.  There are some gotcha's, but if you know them, you can avoid
>> them.
>>
>> Nigel
>>
>> On Thu, 2010-02-25 at 12:54 +1100, Nikolas Bowe wrote:
>> > you need to keep a reference somewhere in lua
>> >
>> > you can use the registry
>> > or you can look at wrap_base
>> > or you can look at transferring pointer ownership between Lua and C++
>> > (ie you could have push_back adopt the pointer into C++)
>> > you can also try a smart pointer holder like tony suggested. (that way
>> > lua just destroys the smart pointer instead of the whole object)
>> >
>> > we use smart pointers and/or wrappers (wrap_base) for most of our
>> > stuff..
>> > we have very few cases of registry stashing and few cases of manual
>> > ownership transfer.
>> >
>> >
>> >
>> > Greg Santucci wrote:
>> > >
>> > > Hi Luabinders,
>> > >
>> > > I've registered some functions of an stl vector using Luabind the
>> > > following way without any problems:
>> [...]
>>
>>
>>
>>
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>
>