Gio.DBusConnection.send_message_with_reply_sync

### Method

# Gio DBusConnectionsend_message_with_reply_sync

since: 2.26

#### Declaration [src]

    GDBusMessage*
    g_dbus_connection_send_message_with_reply_sync (
      GDBusConnection* connection,
      GDBusMessage* message,
      GDBusSendMessageFlags flags,
      gint timeout_msec,
      volatile guint32* out_serial,
      GCancellable* cancellable,
      GError** error
    )

#### Description [src]

Synchronously sends `message` to the peer represented by `connection` and blocks the calling thread until a reply is received or the timeout is reached. See `g_dbus_connection_send_message_with_reply()` for the asynchronous version of this method.

Unless `flags` contain the `G_DBUS_SEND_MESSAGE_FLAGS_PRESERVE_SERIAL` flag, the serial number will be assigned by `connection` and set on `message` via g_dbus_message_set_serial(). If `out_serial` is not `NULL`, then the serial number used will be written to this location prior to submitting the message to the underlying transport. While it has a `volatile` qualifier, this is a historical artifact and the argument passed to it should not be `volatile`.

If `connection` is closed then the operation will fail with `G_IO_ERROR_CLOSED`. If `cancellable` is canceled, the operation will fail with `G_IO_ERROR_CANCELLED`. If `message` is not well-formed, the operation fails with `G_IO_ERROR_INVALID_ARGUMENT`.

Note that `error` is only set if a local in-process error occurred. That is to say that the returned `GDBusMessage` object may be of type `G_DBUS_MESSAGE_TYPE_ERROR`. Use `g_dbus_message_to_gerror()` to transcode this to a `GError`.

See this server and client for an example of how to use this low-level API to send and receive UNIX file descriptors.

Note that `message` must be unlocked, unless `flags` contain the `G_DBUS_SEND_MESSAGE_FLAGS_PRESERVE_SERIAL` flag.

Available since: 2.26

#### Parameters

`message`

  Type: `GDBusMessage`

  A `GDBusMessage`.

  The data is owned by the caller of the method.

`flags`

  Type: `GDBusSendMessageFlags`

  Flags affecting how the message is sent.

`timeout_msec`

  Type: `gint`

  The timeout in milliseconds, -1 to use the default timeout or `G_MAXINT` for no timeout.

`out_serial`

  Type: `volatile guint32*`

  Return location for serial number assigned to `message` when sending it or `NULL`.

  The argument will be set by the function.
  The argument can be `NULL`.

`cancellable`

  Type: `GCancellable`

  A `GCancellable` or `NULL`.

  The argument can be `NULL`.
  The data is owned by the caller of the method.

`error`

  Type: `GError **`

  The return location for a recoverable error.

  The argument can be `NULL`.
  If the return location is not `NULL`, then you must initialize it to a `NULL` `GError*`.
  The argument will be left initialized to `NULL` by the method if there are no errors.
  In case of error, the argument will be set to a newly allocated `GError`; the caller will take ownership of the data, and be responsible for freeing it.

#### Return value

Type: `GDBusMessage`

A locked `GDBusMessage` that is the reply to `message` or `NULL` if `error` is set.

The caller of the method takes ownership of the returned data, and is responsible for freeing it.