diff --git a/wordsplit.c b/wordsplit.c
index 9179a87..d3ec9e1 100644
--- a/wordsplit.c
+++ b/wordsplit.c
@@ -70,6 +70,9 @@ _wsplt_alloc_die (struct wordsplit *wsp)
   abort ();
 }
 
+static void _wsplt_error (const char *fmt, ...)
+   __attribute__ ((format (printf, 1, 2)));
+
 static void
 _wsplt_error (const char *fmt, ...)
 {
@@ -1207,7 +1210,7 @@ wsplt_assign_var (struct wordsplit *wsp, const char *name, size_t namelen,
   return WRDSE_OK;
 }
 
-int
+static int
 wsplt_assign_param (struct wordsplit *wsp, int param_idx, char *value)
 {
   char *v;