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   sd_bus_wait    ( 3 )

дождитесь ввода / вывода при подключении к шине (Wait for I/O on a bus connection)

Имя (Name)

sd_bus_wait - Wait for I/O on a bus connection

Синопсис (Synopsis)

#include <systemd/sd-bus.h>

int sd_bus_wait(sd_bus *bus, uint64_t timeout_usec);


Описание (Description)

sd_bus_wait() synchronously waits for I/O on the specified bus
       connection object. This function is supposed to be called
       whenever sd_bus_process(3) returns zero, indicating that no work
       is pending on the connection. Internally, this call invokes
       ppoll(2), to wait for I/O on the bus connection. If the
       timeout_sec parameter is specified, the call will block at most
       for the specified amount of time in µs. Pass UINT64_MAX to permit
       it to sleep indefinitely.

After each invocation of sd_bus_wait() the sd_bus_process() call should be invoked in order to process any now pending I/O work.

Note that sd_bus_wait() is suitable only for simple programs as it does not permit waiting for other I/O events. For more complex programs either connect the bus connection object to an external event loop using sd_bus_get_fd(3) or to an sd-event(3) event loop using sd_bus_attach_event(3).


Возвращаемое значение (Return value)

If any I/O was seen, a positive value is returned, zero
       otherwise. 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.


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_process(3), sd_bus_get_fd(3),
       sd-event(3), sd_bus_attach_event(3)