управляйте подключением (Drive the connection)
Имя (Name)
sd_bus_process - Drive the connection
Синопсис (Synopsis)
#include <systemd/sd-bus.h>
int sd_bus_process(sd_bus *bus, sd_bus_message **ret);
Описание (Description)
sd_bus_process() drives the connection between the client and the
message bus. That is, it handles connecting, authentication, and
message processing. When invoked pending I/O work is executed,
and queued incoming messages are dispatched to registered
callbacks. Each time it is invoked a single operation is
executed. It returns zero when no operations were pending and
positive if a message was processed. When zero is returned the
caller should synchronously poll for I/O events before calling
into sd_bus_process() again. For that either use the simple,
synchronous sd_bus_wait(3) call, or hook up the bus connection
object to an external or manual event loop using
sd_bus_get_fd(3).
sd_bus_process() processes at most one incoming message per call.
If the parameter ret is not NULL and the call processed a
message, *ret is set to this message. The caller owns a reference
to this message and should call sd_bus_message_unref(3) when the
message is no longer needed. If ret is not NULL, progress was
made, but no message was processed, *ret is set to NULL.
If the bus object is connected to an sd-event(3) event loop (with
sd_bus_attach_event(3)), it is not necessary to call
sd_bus_process() directly as it is invoked automatically when
necessary.
Возвращаемое значение (Return value)
If progress was made, a positive integer is returned. If no
progress was made, 0 is returned. If an error occurs, a negative
errno-style error code is returned.
Errors
Returned errors may indicate the following problems:
-EINVAL
An invalid bus object was passed.
-ECHILD
The bus connection was allocated in a parent process and is
being reused in a child process after fork().
-ENOTCONN
The bus connection has been terminated already.
-ECONNRESET
The bus connection has been terminated just now.
-EBUSY
This function is already being called, i.e. sd_bus_process()
has been called from a callback function that itself was
called by sd_bus_process().
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_wait(3), sd_bus_get_fd(3),
sd_bus_message_unref(3), sd-event(3), sd_bus_attach_event(3)
