+static int inter_extern(struct interface *interface, char *filename, int line, char *parameter, char *value)
+{
+ if (interface->extension) {
+ SPRINT(interface_error, "Error in %s (line %d): parameter '%s' not allowed, because interface is an extension.\n", filename, line, parameter);
+ return(-1);
+ }
+ if (value[0]) {
+ SPRINT(interface_error, "Error in %s (line %d): parameter '%s' expects no value.\n", filename, line, parameter);
+ return(-1);
+ }
+ interface->external = 1;
+ return(0);
+}