sd_bus_send, sd_bus_send_to - Queue a D-Bus message for transfer
int sd_bus_send(sd_bus *bus,
int sd_bus_send_to(sd_bus *bus,
const char *destination,
sd_bus_send() queues the bus message object m for transfer. If
bus is NULL, the bus that m is attached to is used.
bus only needs to be set when the message is sent to a different bus
than the one it's attached to, for example when forwarding messages. If the
output parameter cookie is not NULL, it is set to the message
identifier. This value can later be used to match incoming replies to their
corresponding messages. If cookie is set to NULL and the message
is not sealed, sd_bus_send() assumes the message m doesn't
expect a reply and adds the necessary headers to indicate this.
Note that in most scenarios, sd_bus_send() should not be
called directly. Instead, use higher level functions such as
sd_bus_call_method(3) and sd_bus_reply_method_return(3) which
call sd_bus_send() internally.
sd_bus_send_to() is a shorthand for sending a message to a
specific destination. It's main use case is to simplify sending unicast
signal messages (signals that only have a single receiver). It's behavior is
similar to calling sd_bus_message_set_destination(3) followed by
On success, these functions return a non-negative integer. On failure, they
return a negative errno-style error code.
Returned errors may indicate the following problems:
The input parameter m is NULL.
The bus connection does not support sending file
The bus connection was allocated in a parent process and
is being reused in a child process after fork().
The bus connection's write queue is full.
The input parameter bus is NULL or the bus
is not connected.
The bus connection was closed while waiting for the
Memory allocation failed.
These APIs are implemented as a shared library, which can be compiled and linked
to with the libsystemd pkg-config(1) file.