sd_bus_set_sender, sd_bus_get_sender - Configure default sender for outgoing messages
int sd_bus_set_sender(sd_bus *bus, const char* name);
int sd_bus_get_sender(sd_bus *bus, const char** name);
sd_bus_set_sender() configures the default sender service name to use for outgoing messages. The service name specified in the name parameter is set on all outgoing messages that are sent on the connection and have no sender set yet, for example through sd_bus_message_set_sender(3). Note that this function is only supported on direct connections, i.e. not on connections to a bus broker as the broker will fill in the sender service name automatically anyway. By default no sender name is configured, and hence messages are sent without sender field set. If the name parameter is specified as NULL the default sender service name is cleared, returning to the default state if a default sender service name was set before. If passed as non-NULL the specified name must be a valid unique or well-known service name.
sd_bus_get_sender() may be used to query the current default service name for outgoing messages.
On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style error code.
Returned errors may indicate the following problems:
The bus connection has been created in a different process.
The specified bus connection object is a not a direct but a brokered connection.
These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.