SD_BUS_SLOT_REF

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 m[blue]Clean-up Variable Attributem[][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.  

RETURN VALUE

sd_bus_slot_ref() always returns the argument.

sd_bus_slot_unref() always returns NULL.  

NOTES

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

SEE ALSO

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

NOTES

1.

Clean-up Variable Attribute

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