Is there any way to let compositor set the data in client space and then return back to client?

[Jasper St. Pierre]

What is the "output data"? Is there any reason it needs to be allocated
directly in the client's space, rather than streamed across as part of the
protocol?


On Sun, Feb 9, 2014 at 8:58 PM, Wang, Quanxian <quanxian.wang at intel.com>wrote:

>
>
>
>
> *From:* magcius at gmail.com [mailto:magcius at gmail.com] *On Behalf Of *Jasper
> St. Pierre
> *Sent:* Sunday, February 09, 2014 12:23 AM
>
> *To:* Wang, Quanxian
> *Cc:* wayland-devel at lists.freedesktop.org
> *Subject:* Re: Is there any way to let compositor set the data in client
> space and then return back to client?
>
>
>
> Well, there's not really anything that allows process A to arbitrarily
> modify process B's memory. The only thing that's close is memory-mapped
> files, and that's already what we use to share image data between the
> client and the compositor.
>
> There's also memfd, which is "more secure" than a memory-mapped tmpfile,
> simply because it allows sealing the fd, so you can be sure it will never
> change as you try to read from it. But memfd isn't a public API yet.
>
>
>
> What exactly are you trying to do here?
>
> *[Wang, Quanxian] I want to create a protocol to get the output data from
> compositor, I don't know where to put it for client.  So shared memory
> should be a good way to do that. Anyway,  I need to check it how to make it
> happen. Thanks for your idea.*
>
>
>
> On Sat, Feb 8, 2014 at 3:19 AM, Wang, Quanxian <quanxian.wang at intel.com>
> wrote:
>
> Hi, All
>
>
>
> I want to allocate some space in client, and let compositor set some data
> in this space and then return back to client.
>
>
>
> It seems like user data mechanism.
>
>
>
> Any way to implement that?
>
>
>
> Thanks
>
>
>
> Regards
>
>
>
> Quanxian Wang
>
>
>
>
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>
>
>
>
> --
>   Jasper
>



-- 
  Jasper
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