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double hal_device_get_property_double ( LibHalContext ctx,
const char *  udi,
const char *  key 
)

Get the value of a property of type double.

Parameters:
ctx The context for the connection to hald
udi Unique Device Id
key Name of the property
Returns:
IEEE754 double precision float

Definition at line 1107 of file libhal.c.

References LibHalContext_s::connection.

Referenced by main(), and print_property().

{
      DBusError error;
      DBusMessage *message;
      DBusMessage *reply;
      DBusMessageIter iter;
      double value;

      message = dbus_message_new_method_call ("org.freedesktop.Hal", udi,
                                    "org.freedesktop.Hal.Device",
                                    "GetPropertyDouble");
      if (message == NULL) {
            fprintf (stderr,
                   "%s %d : Couldn't allocate D-BUS message\n",
                   __FILE__, __LINE__);
            return -1.0f;
      }

      dbus_message_iter_init (message, &iter);
      dbus_message_iter_append_string (&iter, key);
      dbus_error_init (&error);
      reply = dbus_connection_send_with_reply_and_block (ctx->connection,
                                             message, -1,
                                             &error);
      if (dbus_error_is_set (&error)) {
            fprintf (stderr, "%s %d : Error sending msg: %s\n",
                   __FILE__, __LINE__, error.message);
            dbus_message_unref (message);
            return -1.0f;
      }
      if (reply == NULL) {
            dbus_message_unref (message);
            return -1.0f;
      }

      dbus_message_iter_init (reply, &iter);

      /* now analyze reply */
      if (dbus_message_iter_get_arg_type (&iter) == DBUS_TYPE_NIL) {
            /* property didn't exist */
            fprintf (stderr,
                   "%s %d : property '%s' for device '%s' does not "
                   "exist\n", __FILE__, __LINE__, key, udi);
            dbus_message_unref (message);
            dbus_message_unref (reply);
            return -1.0f;
      } else if (dbus_message_iter_get_arg_type (&iter) !=
               DBUS_TYPE_DOUBLE) {
            fprintf (stderr,
                   "%s %d : property '%s' for device '%s' is not "
                   "of type double\n", __FILE__, __LINE__, key, udi);
            dbus_message_unref (message);
            dbus_message_unref (reply);
            return -1.0f;
      }
      value = dbus_message_iter_get_double (&iter);

      dbus_message_unref (message);
      dbus_message_unref (reply);
      return (double) value;
}


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