Re: about and

[xie]

hi Dianne~~

thanks for you answer~~ i have implmented the camera hal with v4l2,
although i used the below source, i still have some confusion. I think
the below source is a singleton mode, if the object have been freed we
will creat a new object . when i creat a new object with this code :

sp<CameraHardwareInterface> hardware(new CameraHal());

i think the "hardware" is a temp variable, it will be deleted when the
function return. And the sp is a smartpointer ,it will free the object.
But i am wrong in fact , the object have not been deleted. Can you tell
my where i am wrong ~~

thanks very much 

sp<CameraHardwareInterface> CameraHal::createInstance()
{
    LOG_FUNCTION_NAME

    if (singleton != 0) {
        sp<CameraHardwareInterface> hardware = singleton.promote();
        if (hardware != 0) {
            return hardware;
        }
    }

    sp<CameraHardwareInterface> hardware(new CameraHal());

    singleton = hardware;
    return hardware;
}


在 2009-05-19二的 00:43 -0700，Dianne Hackborn写道：
> sp == strong pointer, wp == weak pointer.
> 
> The object will remain around while there are strong pointers; it is
> destroyed once the last one is released.  All you can do with a weak
> pointer is comparison and attempting to promote to a strong pointer;
> the latter will fail if there are no other strong pointers on the
> object.
> 
> On Mon, May 18, 2009 at 11:56 PM, xie <yili....@gmail.com> wrote:
>         
>         Dear all :
>         
>         when i read the android source, i find that "<sp>" is not only
>         a smart
>         pointer,it manage a strong ref count and i also find that the
>         <wp>
>         manage a weak ref count .
>         
>         who can tell me how the two kinds of pointer works together,
>         when will
>         the object be freed?
>         
>         thanks a lot
>         
>         
>         
> 
> 
> 
> -- 
> Dianne Hackborn
> Android framework engineer
> hack...@android.com
> 
> Note: please don't send private questions to me, as I don't have time
> to provide private support, and so won't reply to such e-mails.  All
> such questions should be posted on public forums, where I and others
> can see and answer them.
> 
> 
> > 


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