sd_bus_add_match — Add a match rule for message dispatching
#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) ; |
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.
On success, sd_bus_add_match()
returns 0 or a
positive integer. On failure, it returns a negative errno-style error
code.