SD_BUS_MESSAGE_NEW_METHOD_ERROR

Section: sd_bus_message_new_method_error (3)
Updated:
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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

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, ...);

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.)

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.

NOTES

These APIs are implemented as a shared library, which can be compiled and linked to with the libsystemd pkg-config(1) file.