sd_bus_reply_method_return, sd_bus_reply_method_returnv — Reply to a D-Bus method call
#include <systemd/sd-bus.h>
| int sd_bus_reply_method_return( | sd_bus_message *call, | 
| const char *types, | |
| ... ); | 
| int sd_bus_reply_method_returnv( | sd_bus_message *call, | 
| const char *types, | |
| va_list ap ); | 
sd_bus_reply_method_return() sends a reply to the
    call message. The type string types and the
    arguments that follow it must adhere to the format described in
    sd_bus_message_append(3).
    If no reply is expected to call, this function succeeds without sending a
    reply.
On success, this function returns a non-negative integer. 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.
Message m is not a method reply message.
-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(3) 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.