[Xcb] [PATCH] Add RandR 1.3 requests

Peter Harris git at peter.is-a-geek.org
Sun Apr 26 13:46:38 PDT 2009

On Sun, Apr 26, 2009 at 4:06 PM, Antoine Latter <aslatter at gmail.com> wrote:
> On Tue, Apr 21, 2009 at 4:37 AM, Julien Cristau <jcristau at debian.org> wrote:
>> +       <request name="SetCrtcTransform" opcode="26">
>> +               <field type="CRTC" name="crtc" />
>> +               <field type="TRANSFORM" name="transform" />
>> +               <field type="CARD16" name="filter_len" />
>> +               <pad bytes="2" />
>> +               <list type="char" name="filter_name">
>> +                       <fieldref>filter_len</fieldref>
>> +               </list>
>> +               <list type="FIXED" name="filter_params" />
>> +       </request>
> I notice that we're introducing a list without a length.  Is there
> some way to specify the length of it, or is it of length "whatever
> we've got left"?

It's "whatever we've got left". The X protocol does this in a number
of places (eg xproto/PolyFillRectangle,

> Also, it looks like there is supposed to be some variable amount of
> padding between filter_name and filter_params.  There are a couple of
> other 1.3 requests that use variable padding between request elements.
>  Do we do this in any other places?  I remember having to cope with
> this in the setup reuest spec as well.

Yes. As you recall, xproto/Setup does this. Also xv/AdaptorInfo, among others.

Implicit padding is a bit of a pain for generator authors, but this is
far from the first use of it in XCB.

Peter Harris

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