Index · Directives systemd 255


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>
typedef int (*sd_bus_message_handler_t)(sd_bus_message *m,
 void *userdata,
 sd_bus_error *ret_error);
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.

Return Value

On success, these functions return the requested object. On failure, they return NULL.


Functions described here are available as a shared library, which can be compiled against and linked to with the libsystemd pkg-config(1) file.

The code described here uses getenv(3), which is declared to be not multi-thread-safe. This means that the code calling the functions described here must not call setenv(3) from a parallel thread. It is recommended to only do calls to setenv() from an early phase of the program when no other threads have been started.


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.

See Also

systemd(1), sd-bus(3)