gboolean g_callable_info_iterate_return_attributes (GICallableInfo* info,
GIAttributeIter* iterator,
char** name,
char** value);
Iterate over all attributes associated with the return value. The iterator structure is typically stack allocated, and must have its first member initialized to %NULL.
Both the @name and @value should be treated as constants and must not be freed.
See g_base_info_iterate_attributes() for an example of how to use a similar API.