how many types would a 'g' type type if a 'g' type would GType?

Robert McQueen robert.mcqueen at
Sat Sep 23 07:33:17 PDT 2006

I'm trying to add support for the 'g' (signature) type to the glib
bindings, and I've run across a slight confusion. I want to marshal a
'g' off the wire into a GType, to tell you what would be inside a GValue
that you got from demarshalling a variant of that type. However, I can't
demarshal a 'g' into a GType value if it represents more than a single
complete type - I'd instead have to make it an array of GTypes. Then
something like 'ag' would be a pointer array of arrays of GTypes...
insanity ensues.

Telepathy wants to use 'g' types to say things like "you may provide
this parameter along with a variant of this type", so we want to only
communicate the type of a single value. Can we tighten up the spec so
that 'g' in a message can represent only one type, or is 'g' used
internally in the message headers etc in a way that relies on it being a
multiple type signature? Could we add a type for a single complete type

Robert McQueen
Director, Collabora Ltd.

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