How to use GVariant ?

[Tiago Katcipis]

Hi (and sorry for the double post on the former luaforge forum),

I'm trying to use lua gnome but it seems to be a problem when you try to use the new GVariant (http://library.gnome.org/devel/glib/2.26/glib-GVariant.html) , the following code gives a segmentation fault:

local glib = require "glib"

glib.type_init()

local variant = glib.variant_new("(s)", "Variant string test !!!")
print("g_variant_print: ", variant:print(true))

variant = nil
print("Collecting GVariant !!!!")
collectgarbage("collect")
print("Garbage collected !!!!")

local loop = glib.main_loop_new(nil, false)
loop:run()

the segmentation fault occurs because luagnome tries to free the GVariant (it will happen between the Collecting and Collected prints).
if you comment the collectgarbage call of the "variant = nil" then it enters the main loop and runs forever just fine.

GVariant uses floating references, i tried to call a refsink on the GVariant:
variant:ref_sink()

the result is the same thing, even calling another ref:
variant:ref_sink()
variant:ref()

…wont help… it always try to free the GVariant and gives a "*** glibc detected *** lua: free(): invalid pointer".

am i using luagnome wrong? or luagnome has some problem with GVariant usage?

also, I'm having trouble getting a string, if i try:

print("Variant message: ", variant:get("(&s)"))
print("Variant message: ", variant:get("(s)"))

after creating the variant…i get no error…no warning… but nothing gets printed… ir prints:
"Variant message: "

any hint on what am i doing wrong?

all tests have been run on Ubuntu 10.10 with glib 2.26.0 and luagnome 0.9 (installed on apt-get).

best regards,
Katcipis

[Wolfgang Oertl]

GVariant has own reference handling functions, i.e. g_variant_ref and g_variant_unref.  This hasn't been supported yet, but now I added some code for that (in current GIT repository). Your example should now work with the exception of the :get() function, which would require an extra handler.