sd_bus_reply_method_error, sd_bus_reply_method_errorf, sd_bus_reply_method_errorfv, sd_bus_reply_method_errno, sd_bus_reply_method_errnof, sd_bus_reply_method_errnofv — Reply with an error to a D-Bus method call
#include <systemd/sd-bus.h>
| int sd_bus_reply_method_error( | sd_bus_message *call, | 
| const sd_bus_error *e ); | 
| int sd_bus_reply_method_errorf( | sd_bus_message *call, | 
| const char *name, | |
| const char *format, | |
| ... ); | 
| int sd_bus_reply_method_errorfv( | sd_bus_message *call, | 
| const char *name, | |
| const char *format, | |
| va_list ap ); | 
| int sd_bus_reply_method_errno( | sd_bus_message *call, | 
| int error, | |
| const sd_bus_error *p ); | 
| int sd_bus_reply_method_errnof( | sd_bus_message *call, | 
| int error, | |
| const char *format, | |
| ... ); | 
| int sd_bus_reply_method_errnofv( | sd_bus_message *call, | 
| int error, | |
| const char *format, | |
| va_list ap ); | 
The sd_bus_reply_method_error() function sends an error reply to the
    call message. The error structure e specifies the
    error to send, and is used as described in
    sd_bus_message_new_method_error(3).
    If no reply is expected to call, this function succeeds without sending a
    reply.
The sd_bus_reply_method_errorf() is to
    sd_bus_reply_method_error() what
    sd_bus_message_new_method_errorf() is to
    sd_bus_message_new_method_error().
The sd_bus_reply_method_errno() is to
    sd_bus_reply_method_error() what
    sd_bus_message_new_method_errno() is to
    sd_bus_message_new_method_error().
The sd_bus_reply_method_errnof() is to
    sd_bus_reply_method_error() what
    sd_bus_message_new_method_errnof() is to
    sd_bus_message_new_method_error().
This function returns a non-negative integer if the error reply was successfully sent or
    if call does not expect a reply. On failure, it returns a negative
    errno-style error code.
Returned errors may indicate the following problems:
-EINVAL¶The input parameter call is
          NULL.
Message call is not a method call message.
Message call is not attached to a bus.
The error parameter e to
          sd_bus_reply_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.
In addition, any error returned by sd_bus_send(1) may be returned.
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.