Чтение базового типа из сообщения (Read a basic type from a message)
Возвращаемое значение (Return value)
On success, sd_bus_message_read_basic() returns a positive
integer. If the end of the currently opened array has been
reached, it returns 0. On failure, it returns a negative
errno-style error code.
Errors
Returned errors may indicate the following problems:
-EINVAL
Specified type string is invalid or the message parameter is
NULL.
-ENXIO
The message does not contain the specified type at current
position.
-EBADMSG
The message cannot be parsed.
