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   sd_bus_send_to    ( 3 )

поставить в очередь сообщение D-Bus для передачи (Queue a D-Bus message for transfer)

Имя (Name)

sd_bus_send, sd_bus_send_to, sd_bus_message_send - Queue a D-Bus
       message for transfer

Синопсис (Synopsis)

#include <systemd/sd-bus.h>

int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *cookie);

int sd_bus_send_to(sd_bus *bus, sd_bus_message *m, const char *destination, uint64_t *cookie);

int sd_bus_message_send(sd_bus_message *m);


Описание (Description)

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 calling sd_bus_send().

sd_bus_send()/sd_bus_send_to() will write the message directly to the underlying transport (e.g. kernel socket buffer) if possible. If the connection is not set up fully yet the message is queued locally. If the transport buffers are congested any unwritten message data is queued locally, too. If the connection has been closed or is currently being closed the call fails. sd_bus_process(3) should be invoked to write out any queued message data to the transport.

sd_bus_message_send() is the same as sd_bus_send() but without the first and last argument. sd_bus_message_send(m) is equivalent to sd_bus_send(sd_bus_message_get_bus(m), m, NULL).


Возвращаемое значение (Return value)

On success, these functions return a non-negative integer. On
       failure, they return a negative errno-style error code.

Errors Returned errors may indicate the following problems:

-EINVAL The input parameter m is NULL.

-EOPNOTSUPP The bus connection does not support sending file descriptors.

-ECHILD The bus connection was allocated in a parent process and is being reused in a child process after fork().

-ENOBUFS The bus connection's write queue is full.

-ENOTCONN The input parameter bus is NULL or the bus is not connected.

-ECONNRESET The bus connection was closed while waiting for the response.

-ENOMEM Memory allocation failed.


Примечание (Note)

These APIs are implemented as a shared library, which can be
       compiled and linked to with the libsystemd pkg-config(1) file.

Смотри также (See also)

systemd(1), sd-bus(3), sd_bus_call_method(3),
       sd_bus_message_set_destination(3), sd_bus_reply_method_return(3),
       sd_bus_process(3)