Somehow the original message never reached my inbox, luckily a colleague
pointed this message out to me :).
I'd be happier to pull this if it had a reviewed-by tag from someone
with a bit of xcb knowledge (which is why I've cc'ed the xcb mailing list).
That would be nice. The xcb proto of the update wasn't probably
introduced at the proper channels earlier..
One thing I note is the comment before "QueryClientIds" says v2.0 where
it presumably should be v1.2.
Indeed, the version number is wrong.
I'm also unsure about the <struct name="ClientIdValue"> definition,
where the XResproto.h header says:
CARD32 length B32;
// followed by length CARD32s
Hmm, this comment is actually wrong. According to resproto.txt it is
followed by CARD32s, but length is in multiples of 4. In the case of PID
its value is 4. I shall quote the passage (lines 127+ of resourceproto.txt):
CLIENTIDVALUE [ spec: CLIENTIDSPEC
length: CARD32
value: LISTofCARD32 ]
A data structure specifying a single client ID.
spec
A unique identifier for a specific ID of some client. Wildcards
such as None and bitmask unions aren't allowed. The data structure
must always identify a single client and single ID type. However,
the client doesn't have to be specified as the resource_base of
CLIENTXIDRANGE and can be any resource owned by the client.
length
Specifies the length of an ID in units of CARD32. The length
depends on the ID type. In version 1.2 the lengths are 0 for
ClientXid and 4 for LocalClientPid. The length of ClientXid is 0
because that is already stored in the spec field.
value
Actual ID data. In version 1.2 this is missing for ClientXid and
consists of a single CARD32 for LocalClientPid.
Perhaps resourceproto.txt could be revised to state that value is
LISTofCARD8, but how would the alignment requirements then be indicated?
the res.xml has CARD8's instead of CARD32's:
<field type="CARD32" name="length" />
<list type="CARD8" name="client_ids">
<fieldref>length</fieldref>
</list>
CARD8 seems too short for a pid_t, but perhaps I'm misunderstanding the
xcb type handling?
Which is what is stated here: the field actually contains opaque data,
so a pid is stored in four octets. But perhaps it should be better
written something like (if the previous specification was revised):
<list type="CARD32" name="client_ids">
<op>/</op>
<op>+</op>
<fieldref>length</fieldref>
<value>3</value>
</op>
</op>
</list>
or not, hopefully someone can chime in. It would be nice to express that
the padding isn't part of the data. Or does it automatically get padded
to 4 bytes?
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