[Xcb] compiler padding and sync extension

Peter Harris pharris at opentext.com
Tue Aug 18 07:35:22 PDT 2009

Aaron Young wrote:
> While playing around with the sync extension using XCB, I've
> apparently come across the same issue mentioned here:
> http://lists.freedesktop.org/archives/xcb/2007-August/002970.html,
> which seems to have fallen between the cracks somewhere.

Hmm, yes, it does seem to have fallen between the cracks. Sorry about that.

> I'm no expert, but I was a little surprised to discover that XCB
> structures weren't already defined with __attribute__ ((packed)),
> #pragma pack(1), etc.  Any reason this approach hasn't been adopted?

Those are not even remotely portable.

(Also, historically, XCB depended on the compiler's implicit padding in
a number of places. That isn't the case any more, modulo bugs).

> Does the sync extension not get enough use to warrant fixing this?

It's not that. The (few) developers that work on XCB do so in their free
time. That means that issues don't always get acted on immediately, and
in extreme cases may even fall through the cracks (sorry again).

If someone were to propose a patch to fix this, it would probably speed
up the process quite a bit (hint, hint).

 Peter Harris
               Open Text Connectivity Solutions Group
Peter Harris                    http://www.opentext.com/connectivity
Research and Development        Phone: +1 905 762 6001
pharris at opentext.com            Toll Free: 1 877 359 4866

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