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)
