Manpages - 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 reference counter of slot by one.

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 GCCs and LLVMs Clean-up Variable Attribute[1]. 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_ref() always returns the argument.

sd_bus_slot_unref() always returns NULL.

These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd *pkg-config*(1) file.

*systemd*(1), *sd-bus*(3), *sd_bus_new*(3), *sd_bus_message_new*(3), *sd_bus_call_method_async*(3)

1.

Clean-up Variable Attribute

https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html