+static int
+pre_os(PRE_ARGS)
+{
+
+ if (NULL == mdoc->meta.title || 0 == mdoc->meta.date)
+ if ( ! mdoc_nwarn(mdoc, n, WARN_COMPAT,
+ "out-of-order prologue"))
+ return(0);
+ if (mdoc->meta.os)
+ if ( ! mdoc_nwarn(mdoc, n, WARN_COMPAT,
+ "prologue re-invoked"))
+ return(0);
+ return(1);
+}
+
+
+static int
+pre_dd(PRE_ARGS)
+{
+
+ if (mdoc->meta.title || mdoc->meta.os)
+ if ( ! mdoc_nwarn(mdoc, n, WARN_COMPAT,
+ "out-of-order prologue"))
+ return(0);
+ if (mdoc->meta.date)
+ if ( ! mdoc_nwarn(mdoc, n, WARN_COMPAT,
+ "prologue re-invoked"))
+ return(0);
+ return(1);