<div dir="ltr">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? </div><div class="gmail_extra"> <div class="gmail_quote">On Sun, Feb 9, 2014 at 8:58 PM, Wang, Quanxian <<a href="mailto:quanxian.wang@intel.com" target="_blank">quanxian.wang@intel.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div link="blue" vlink="purple" lang="ZH-CN"> <div> From: <a href="mailto:magcius@gmail.com" target="_blank">magcius@gmail.com</a> [mailto:<a href="mailto:magcius@gmail.com" target="_blank">magcius@gmail.com</a>] On Behalf Of Jasper St. Pierre Sent: Sunday, February 09, 2014 12:23 AM<div class=""> To: Wang, Quanxian Cc: <a href="mailto:wayland-devel@lists.freedesktop.org" target="_blank">wayland-devel@lists.freedesktop.org</a> </div>Subject: Re: Is there any way to let compositor set the data in client space and then return back to client? <div><div class=""> <div> 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. </div> <div> 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. </div> <div> </div> What exactly are you trying to do here? </div>[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. </div><div class=""> <div> <div> On Sat, Feb 8, 2014 at 3:19 AM, Wang, Quanxian <<a href="mailto:quanxian.wang@intel.com" target="_blank">quanxian.wang@intel.com</a>> wrote: <div> 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 </div> _______________________________________________ wayland-devel mailing list <a href="mailto:wayland-devel@lists.freedesktop.org" target="_blank">wayland-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/wayland-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/wayland-devel</a> </div> -- Jasper </div> </div></div> </div> </blockquote></div> -- Jasper </div>