[vbox-dev] IFramebuffer - requestResize vram question

[Klaus Espenlaub]

On 27.04.2012 08:56, Jaikumar G wrote:
>
>
> On Thu, Apr 26, 2012 at 10:48 PM, Klaus Espenlaub
> <klaus.espenlaub at oracle.com <mailto:klaus.espenlaub at oracle.com>> wrote:
>
>     On 27.04.2012 02 <tel:27.04.2012%2002>:43, Jaikumar G wrote:
>      > Folks,
>      > https://www.virtualbox.org/sdkref/interface_i_framebuffer.html -
>      > requestResize function says that in direct mode the Vram pointer
>     content
>      > can be blitted into the window showing the display.
>      >
>      > Is this vram pointer pointing to a shared memory location
>     accessible by
>      > another process ? I just tried to access it and it segfaults.
>      >
>      > Is my understanding of the API incorrect ? If I want to have the
>     display
>      > in another process - can I access the vram pointer directly -
>     instead of
>      > creating a shared buffer and passing it in the IFramebuffer
>     implementation ?
>
>     This interface method isn't directly intended for using shared memory
>     (but it might work if the VM frontend knows how to handle it), and it
>     can only be used by the VM frontend itself, as pointers make no sense
>     across processes.
>
>
> So whats the recommended way of sharing the display buffer if the
> frontend is running in another process ?

There is no recommended way so far - we didn't have the need for moving 
the display buffer into another process, and others didn't need it 
either. Heard of several people who rolled their own VM frontend (some 
even in VisualBasic), keeping the display buffer local. It's the most 
efficient solution, as it keeps the screen updates (which need a very 
high bandwidth with a low latency to give a good interactive 
performance) withing the process.

If you really want to go there you're the pioneer.

Klaus

>
>
>     Klaus
>
>      >
>      > Thanks
>
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>
>


-- 
Oracle <http://www.oracle.com>
Dr. Klaus Espenlaub | Snr. Manager Software Development Desktop
Virtualization
Phone: +49 7151 60405 205 <tel:+49715160405205>
Oracle VM VirtualBox

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