Sets an opaque, named pointer on a #GParamSpec. The name is
specified through a #GQuark (retrieved e.g. via
glib.global.quarkFromStaticString), and the pointer can be gotten back
from the pspec with gobject.param_spec.ParamSpec.getQdata. Setting a
previously set user data pointer, overrides (frees) the old pointer
set, using null as pointer essentially removes the data stored.
Sets an opaque, named pointer on a #GParamSpec. The name is specified through a #GQuark (retrieved e.g. via glib.global.quarkFromStaticString), and the pointer can be gotten back from the pspec with gobject.param_spec.ParamSpec.getQdata. Setting a previously set user data pointer, overrides (frees) the old pointer set, using null as pointer essentially removes the data stored.