sd_bus_slot *sd_bus_slot_ref(sd_bus_slot *slot);
sd_bus_slot *sd_bus_slot_unref(sd_bus_slot *slot);
void sd_bus_slot_unrefp(sd_bus_slot **slotp);
sd_bus_slot_unref() decreases the reference counter of slot by one. Once the reference count has dropped to zero, slot object is destroyed and cannot be used anymore, so further calls to sd_bus_slot_ref() or sd_bus_slot_unref() are illegal.
sd_bus_slot_unrefp() is similar to sd_bus_slot_unref() but takes a pointer to a pointer to an sd_bus_slot object. This call is useful in conjunction with GCC's and LLVM's Clean-up Variable Attribute. See sd_bus_new(3) for an example how to use the cleanup attribute.
sd_bus_slot_ref() and sd_bus_slot_unref() execute no operation if the passed in bus object address is NULL. sd_bus_slot_unrefp() will first dereference its argument, which must not be NULL, and will execute no operation if that is NULL.
sd_bus_slot_unref() always returns NULL.
- Clean-up Variable Attribute