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

       Functions described here are available as a shared library, which can be compiled against
       and linked to with the libsystemd pkg-config(1) file.

       The code described here uses getenv(3), which is declared to be not multi-thread-safe.
       This means that the code calling the functions described here must not call setenv(3) from
       a parallel thread. It is recommended to only do calls to setenv() from an early phase of
       the program when no other threads have been started.

SEE ALSO

       systemd(1), sd-bus(3)