Either technique works. I've blessed my objects at the C level (though I use XS, not Inline::C). In addition, I've used the '~' magic to store an SV that holds the pointer to the data for the C struct that describes the object.

Something like

thv = (HV*)sv_2mortal((SV*)newHV());
sv = newSViv((IV)info);
sv_magic((SV*)thv, sv, '~', "CTlib", 5);
SvRMAGICAL_on((SV*)thv);

rv = newRV((SV*)thv);
stash = gv_stashpv("Sybase::CTlib::_attribs", TRUE);
(void)sv_bless(rv, stash);
[download]

Then you can get the "info" structure from the hashref via mg_find().

Note that this code is pretty old, and there might be better ways to do this sort of things in more recent versions of perl.

Michael