On 12/01/2011 01:35 PM, Stefan Hajnoczi wrote: > >> > >> +static void qdev_get_link_property(DeviceState *dev, Visitor *v, void > >> *opaque, > >> + const char *name, Error **errp) > >> +{ > >> + DeviceState **child = opaque; > >> + gchar *path; > >> + > >> + if (*child) { > >> + path = qdev_get_canonical_path(*child); > >> + visit_type_str(v, &path, name, errp); > >> + g_free(path); > >> + } else { > >> + path = (gchar *)""; > > > > If gchar != char, this is wrong. Also, you're converting a const > > pointer into a non-const pointer, discarding type safety. > > This looked weird to me too but the cast has to do with the fact that > the visitor function works both for input and output visitors. The > output visitor needs to write to gchar** while the input visitor does > not.
So you need to pass a non-const pointer to an array of const char, or const gchar **. You don't modify the string in place, you allocate a new string and free the old one. > When this function is called with the correct visitor type we are > guaranteed that path will not be modified. What if it's called with the output visitor? (warning: confusing convention). -- error compiling committee.c: too many arguments to function