1SD_BUS_PROCESS(3)               sd_bus_process               SD_BUS_PROCESS(3)
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NAME

6       sd_bus_process - Drive the connection
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SYNOPSIS

9       #include <systemd/sd-bus.h>
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11       int sd_bus_process(sd_bus *bus, sd_bus_message **ret);
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DESCRIPTION

14       sd_bus_process() drives the connection between the client and the
15       message bus. That is, it handles connecting, authentication, and
16       message processing. When invoked pending I/O work is executed, and
17       queued incoming messages are dispatched to registered callbacks. Each
18       time it is invoked a single operation is executed. It returns zero when
19       no operations were pending and positive if a message was processed.
20       When zero is returned the caller should synchronously poll for I/O
21       events before calling into sd_bus_process() again. For that either user
22       the simple, synchronous sd_bus_wait(3) call, or hook up the bus
23       connection object to an external or manual event loop using
24       sd_bus_get_fd(3).
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26       sd_bus_process() processes at most one incoming message per call. If
27       the parameter ret is not NULL and the call processed a message, *ret is
28       set to this message. The caller owns a reference to this message and
29       should call sd_bus_message_unref(3) when the message is no longer
30       needed. If ret is not NULL, progress was made, but no message was
31       processed, *ret is set to NULL.
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33       If a the bus object is connected to an sd-event(3) event loop (with
34       sd_bus_attach_event(3)), it is not necessary to call sd_bus_process()
35       directly as it is invoked automatically when necessary.
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RETURN VALUE

38       If progress was made, a positive integer is returned. If no progress
39       was made, 0 is returned. If an error occurs, a negative errno-style
40       error code is returned.
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42   Errors
43       Returned errors may indicate the following problems:
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45       -EINVAL
46           An invalid bus object was passed.
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48       -ECHILD
49           The bus connection was allocated in a parent process and is being
50           reused in a child process after fork().
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52       -ENOTCONN
53           The bus connection has been terminated already.
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55       -ECONNRESET
56           The bus connection has been terminated just now.
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58       -EBUSY
59           This function is already being called, i.e.  sd_bus_process() has
60           been called from a callback function that itself was called by
61           sd_bus_process().
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NOTES

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

68       systemd(1), sd-bus(3), sd_bus_wait(3), sd_bus_get_fd(3),
69       sd_bus_message_unref(3), sd-event(3), sd_bus_attach_event(3)
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73systemd 243                                                  SD_BUS_PROCESS(3)
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