systemd sd_bus_get_current_handler 3 sd_bus_get_current_handler sd_bus_get_current_message sd_bus_get_current_slot sd_bus_get_current_userdata Query information of the callback a bus object is currently running #include <systemd/sd-bus.h> sd_bus_message_handler_t sd_bus_get_current_handler sd_bus *bus sd_bus_message* sd_bus_get_current_message sd_bus *bus sd_bus_slot* sd_bus_get_current_slot sd_bus *bus void* sd_bus_get_current_userdata sd_bus *bus Whenever sd-bus is about to invoke a user-supplied callback function, it stores the current callback, D-Bus message, slot and userdata pointer and allows these to be queried via sd_bus_get_current_handler(), sd_bus_get_current_message(), sd_bus_get_current_slot() and sd_bus_get_current_userdata(), respectively. If bus cannot be resolved or if execution does not reside in a user-supplied callback of bus, these functions return NULL. On success, these functions return the requested object. On failure, they return NULL. sd_bus_get_current_handler(), sd_bus_get_current_message(), sd_bus_get_current_slot(), and sd_bus_get_current_userdata() were added in version 246. systemd1 sd-bus3