создать ответ об ошибке для вызова метода (create an error reply for a method call)
Имя (Name)
sd_bus_message_new_method_error,
sd_bus_message_new_method_errorf,
sd_bus_message_new_method_errno, sd_bus_message_new_method_errnof
- Create an error reply for a method call
Синопсис (Synopsis)
#include <systemd/sd-bus.h>
int sd_bus_message_new_method_error(sd_bus_message *call,
sd_bus_message **m,
const sd_bus_error *e);
int sd_bus_message_new_method_errorf(sd_bus_message *call,
sd_bus_message **m,
const char *name,
const char *format, ...);
int sd_bus_message_new_method_errno(sd_bus_message *call,
sd_bus_message **m,
int error,
const sd_bus_error *p);
int sd_bus_message_new_method_errnof(sd_bus_message *call,
sd_bus_message **m,
int error,
const char *format, ...);
Описание (Description)
The sd_bus_message_new_method_error() function creates a new bus
message object that is an error reply to the call message, and
returns it in the m output parameter. The error information from
error e is appended: the name field of e is used as the error
identifier in the reply header (for example an error name such as
"org.freedesktop.DBus.Error.NotSupported" or the equivalent
symbolic SD_BUS_ERROR_NOT_SUPPORTED), and the message field is
set as the human readable error message string if present. The
error e must have the name field set, see sd_bus_error_is_set(3).
The sd_bus_message_new_method_errorf() function creates an error
reply similarly to sd_bus_message_new_method_error(), but instead
of a ready error structure, it takes an error identifier string
name, plus a printf(3) format string format and corresponding
arguments. An error reply is sent with the error identifier name
and the formatted string as the message. name and format must
not be NULL.
The sd_bus_message_new_method_errno() function creates an error
reply similarly to sd_bus_message_new_method_error(), but in
addition to the error structure p, it takes an errno(3) error
value in parameter error. If the error p is set (see
sd_bus_error_is_set(3)), it is used in the reply. Otherwise,
error is translated to an error identifier and used to create a
new error structure using sd_bus_error_set_errno(3) and that is
used in the reply. (If error is zero, no error is actually set,
and an error reply with no information is created.)
The sd_bus_message_new_method_errnof() function creates an error
reply similarly to sd_bus_message_new_method_error(). It takes an
errno(3) error value in parameter error, plus a printf(3) format
string format and corresponding arguments. "%m" may be used in
the format string to refer to the error string corresponding to
the specified errno code. The error message is initialized using
the error identifier generated from error and the formatted
string. (If error is zero, no error is actually set, and an error
reply with no information is created.)
Возвращаемое значение (Return value)
These functions return 0 if the error reply was successfully
created, and a negative errno-style error code otherwise.
Errors
Returned errors may indicate the following problems:
-EINVAL
The call message call or the output parameter m are NULL.
Message call is not a method call message.
The error e parameter to sd_bus_message_new_method_error() is
not set, see sd_bus_error_is_set(3).
-EPERM
Message call has been sealed.
-ENOTCONN
The bus to which message call is attached is not connected.
-ENOMEM
Memory allocation failed.
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)
