'\" t
.TH "SD_BUS_MESSAGE_NEW_METHOD_ERROR" "3" "" "systemd 255" "sd_bus_message_new_method_error"
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.SH "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
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.HP \w'int\ sd_bus_message_new_method_error('u
.BI "int sd_bus_message_new_method_error(sd_bus_message\ *" "call" ", sd_bus_message\ **" "m" ", const\ sd_bus_error\ *" "e" ");"
.HP \w'int\ sd_bus_message_new_method_errorf('u
.BI "int sd_bus_message_new_method_errorf(sd_bus_message\ *" "call" ", sd_bus_message\ **" "m" ", const\ char\ *" "name" ", const\ char\ *" "format" ", \&...);"
.HP \w'int\ sd_bus_message_new_method_errno('u
.BI "int sd_bus_message_new_method_errno(sd_bus_message\ *" "call" ", sd_bus_message\ **" "m" ", int\ " "error" ", const\ sd_bus_error\ *" "p" ");"
.HP \w'int\ sd_bus_message_new_method_errnof('u
.BI "int sd_bus_message_new_method_errnof(sd_bus_message\ *" "call" ", sd_bus_message\ **" "m" ", int\ " "error" ", const\ char\ *" "format" ", \&...);"
.SH "DESCRIPTION"
.PP
The
\fBsd_bus_message_new_method_error()\fR
function creates a new bus message object that is an error reply to the
\fIcall\fR
message, and returns it in the
\fIm\fR
output parameter\&. The error information from error
\fIe\fR
is appended: the
\fIname\fR
field of
\fIe\fR
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
\fBSD_BUS_ERROR_NOT_SUPPORTED\fR), and the
\fImessage\fR
field is set as the human readable error message string if present\&. The error
\fIe\fR
must have the
\fIname\fR
field set, see
\fBsd_bus_error_is_set\fR(3)\&.
.PP
The
\fBsd_bus_message_new_method_errorf()\fR
function creates an error reply similarly to
\fBsd_bus_message_new_method_error()\fR, but instead of a ready error structure, it takes an error identifier string
\fIname\fR, plus a
\fBprintf\fR(3)
format string
\fIformat\fR
and corresponding arguments\&. An error reply is sent with the error identifier
\fIname\fR
and the formatted string as the message\&.
\fIname\fR
and
\fIformat\fR
must not be
\fBNULL\fR\&.
.PP
The
\fBsd_bus_message_new_method_errno()\fR
function creates an error reply similarly to
\fBsd_bus_message_new_method_error()\fR, but in addition to the error structure
\fIp\fR, it takes an
\fBerrno\fR(3)
error value in parameter
\fIerror\fR\&. If the error
\fIp\fR
is set (see
\fBsd_bus_error_is_set\fR(3)), it is used in the reply\&. Otherwise,
\fIerror\fR
is translated to an error identifier and used to create a new error structure using
\fBsd_bus_error_set_errno\fR(3)
and that is used in the reply\&. (If
\fIerror\fR
is zero, no error is actually set, and an error reply with no information is created\&.)
.PP
The
\fBsd_bus_message_new_method_errnof()\fR
function creates an error reply similarly to
\fBsd_bus_message_new_method_error()\fR\&. It takes an
\fBerrno\fR(3)
error value in parameter
\fIerror\fR, plus a
\fBprintf\fR(3)
format string
\fIformat\fR
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
\fBerror\fR
and the formatted string\&. (If
\fIerror\fR
is zero, no error is actually set, and an error reply with no information is created\&.)
.SH "RETURN VALUE"
.PP
These functions return 0 if the error reply was successfully created, and a negative errno\-style error code otherwise\&.
.SS "Errors"
.PP
Returned errors may indicate the following problems:
.PP
\fB\-EINVAL\fR
.RS 4
The call message
\fIcall\fR
or the output parameter
\fIm\fR
are
\fBNULL\fR\&.
.sp
Message
\fIcall\fR
is not a method call message\&.
.sp
The error
\fIe\fR
parameter to
\fBsd_bus_message_new_method_error()\fR
is not set, see
\fBsd_bus_error_is_set\fR(3)\&.
.RE
.PP
\fB\-EPERM\fR
.RS 4
Message
\fIcall\fR
has been sealed\&.
.RE
.PP
\fB\-ENOTCONN\fR
.RS 4
The bus to which message
\fIcall\fR
is attached is not connected\&.
.RE
.PP
\fB\-ENOMEM\fR
.RS 4
Memory allocation failed\&.
.RE
.SH "NOTES"
.PP
Functions described here are available as a shared library, which can be compiled against and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.PP
The code described here uses
\fBgetenv\fR(3), which is declared to be not multi\-thread\-safe\&. This means that the code calling the functions described here must not call
\fBsetenv\fR(3)
from a parallel thread\&. It is recommended to only do calls to
\fBsetenv()\fR
from an early phase of the program when no other threads have been started\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsd-bus\fR(3)