===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/awk/b.c,v
retrieving revision 1.23
retrieving revision 1.24
diff -u -r1.23 -r1.24
--- src/usr.bin/awk/b.c	2020/06/10 21:01:50	1.23
+++ src/usr.bin/awk/b.c	2020/06/10 21:02:19	1.24
@@ -1,4 +1,4 @@
-/*	$OpenBSD: b.c,v 1.23 2020/06/10 21:01:50 millert Exp $	*/
+/*	$OpenBSD: b.c,v 1.24 2020/06/10 21:02:19 millert Exp $	*/
 /****************************************************************
 Copyright (C) Lucent Technologies 1997
 All Rights Reserved
@@ -920,6 +920,7 @@
 	int i;
 	int num, m, commafound, digitfound;
 	const uschar *startreptok;
+	static int parens = 0;
 
 rescan:
 	starttok = prestr;
@@ -933,9 +934,18 @@
 	case '\0': prestr--; return '\0';
 	case '^':
 	case '$':
+		return c;
 	case '(':
-	case ')':
+		parens++;
 		return c;
+	case ')':
+		if (parens) {
+			parens--;
+			return c;
+		}
+		/* unmatched close parenthesis; per POSIX, treat as literal */
+		rlxval = c;
+		return CHAR;
 	case '\\':
 		rlxval = quoted(&prestr);
 		return CHAR;