systemd sd_bus_slot_ref 3 sd_bus_slot_ref sd_bus_slot_unref sd_bus_slot_unrefp Create and destroy references to a bus slot object #include <systemd/sd-bus.h> 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_ref() increases the internal reference counter of slot by one. sd_bus_slot_unref() decreases the internal 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_new3 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_ref() always returns the argument. sd_bus_slot_unref() always returns NULL. sd_bus_slot_ref(), sd_bus_slot_unref(), and sd_bus_slot_unrefp() were added in version 240. systemd1 sd-bus3 sd_bus_new3 sd_bus_message_new3 sd_bus_call_method_async3