Index · Directives systemd 232

Name

sd_bus_add_match — Add a match rule for message dispatching

Synopsis

#include <systemd/sd-bus.h>
int sd_bus_add_match(sd_bus *bus,
 sd_bus_slot **slot,
 const char *match,
 sd_bus_message_handler_t callback,
 void *userdata);
 
typedef int (*sd_bus_message_handler_t)(sd_bus_message *m,
 void *userdata,
 sd_bus_error *ret_error);
 

Description

sd_bus_add_match() adds a match rule used to dispatch incoming messages. The syntax of the rule passed in match is described in the D-Bus Specification.

The message m passed to the callback is only borrowed, that is, the callback should not call sd_bus_message_unref(3) on it. If the callback wants to hold on to the message beyond the lifetime of the callback, it needs to call sd_bus_message_ref(3) to create a new reference.

If an error occurs during the callback invocation, the callback should return a negative error number. If it wants other callbacks that match the same rule to be called, it should return 0. Otherwise it should return a positive integer.

Return Value

On success, sd_bus_add_match() returns 0 or a positive integer. On failure, it returns a negative errno-style error code.

See Also

systemd(1), sd-bus(3),