1SD_BUS_SEND(3)                    sd_bus_send                   SD_BUS_SEND(3)
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NAME

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

10       #include <systemd/sd-bus.h>
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12       int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *cookie);
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14       int sd_bus_send_to(sd_bus *bus, sd_bus_message *m,
15                          const char *destination, uint64_t *cookie);
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17       int sd_bus_message_send(sd_bus_message *m);
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DESCRIPTION

20       sd_bus_send() queues the bus message object m for transfer. If bus is
21       NULL, the bus that m is attached to is used.  bus only needs to be set
22       when the message is sent to a different bus than the one it's attached
23       to, for example when forwarding messages. If the output parameter
24       cookie is not NULL, it is set to the message identifier. This value can
25       later be used to match incoming replies to their corresponding
26       messages. If cookie is set to NULL and the message is not sealed,
27       sd_bus_send() assumes the message m doesn't expect a reply and adds the
28       necessary headers to indicate this.
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30       Note that in most scenarios, sd_bus_send() should not be called
31       directly. Instead, use higher level functions such as
32       sd_bus_call_method(3) and sd_bus_reply_method_return(3) which call
33       sd_bus_send() internally.
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35       sd_bus_send_to() is a shorthand for sending a message to a specific
36       destination. It's main use case is to simplify sending unicast signal
37       messages (signals that only have a single receiver). It's behavior is
38       similar to calling sd_bus_message_set_destination(3) followed by
39       calling sd_bus_send().
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41       sd_bus_send()/sd_bus_send_to() will write the message directly to the
42       underlying transport (e.g. kernel socket buffer) if possible. If the
43       connection is not set up fully yet the message is queued locally. If
44       the transport buffers are congested any unwritten message data is
45       queued locally, too. If the connection has been closed or is currently
46       being closed the call fails.  sd_bus_process(3) should be invoked to
47       write out any queued message data to the transport.
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49       sd_bus_message_send() is the same as sd_bus_send() but without the
50       first and last argument.  sd_bus_message_send(m) is equivalent to
51       sd_bus_send(sd_bus_message_get_bus(m), m, NULL).
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RETURN VALUE

54       On success, these functions return a non-negative integer. On failure,
55       they return a negative errno-style error code.
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57   Errors
58       Returned errors may indicate the following problems:
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60       -EINVAL
61           The input parameter m is NULL.
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63       -EOPNOTSUPP
64           The bus connection does not support sending file descriptors.
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66       -ECHILD
67           The bus connection was allocated in a parent process and is being
68           reused in a child process after fork().
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70       -ENOBUFS
71           The bus connection's write queue is full.
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73       -ENOTCONN
74           The input parameter bus is NULL or the bus is not connected.
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76       -ECONNRESET
77           The bus connection was closed while waiting for the response.
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79       -ENOMEM
80           Memory allocation failed.
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NOTES

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

87       systemd(1), sd-bus(3), sd_bus_call_method(3),
88       sd_bus_message_set_destination(3), sd_bus_reply_method_return(3),
89       sd_bus_process(3)
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93systemd 249                                                     SD_BUS_SEND(3)
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