diff --git a/regex/regerror.c b/regex/regerror.c
index 0a7b7c8da2c..9caa5b95a4c 100644
--- a/regex/regerror.c
+++ b/regex/regerror.c
@@ -56,11 +56,7 @@ static struct rerr {
  */
 /* ARGSUSED */
 size_t
-regerror(errcode, preg, errbuf, errbuf_size)
-int errcode;
-const regex_t *preg;
-char *errbuf;
-size_t errbuf_size;
+regerror(int errcode, const regex_t *preg, char *errbuf, size_t errbuf_size)
 {
 	register struct rerr *r;
 	register size_t len;