diff --git a/lib/isc/include/isc/result.h b/lib/isc/include/isc/result.h
index 1f5e4c155f..0e91c78311 100644
--- a/lib/isc/include/isc/result.h
+++ b/lib/isc/include/isc/result.h
@@ -48,7 +48,8 @@ typedef unsigned int isc_result_t;
 #define ISC_R_FAILURE			25	/* generic failure */
 #define ISC_R_IOERROR			26
 #define ISC_R_NOTIMPLEMENTED		27
-#define ISC_R_LASTENTRY			27	/* last entry in the list */
+#define ISC_R_UNBALANCED		28
+#define ISC_R_LASTENTRY			28	/* last entry in the list */
 
 #define ISC_R_UNEXPECTED		0xFFFFFFFFL
 
diff --git a/lib/isc/result.c b/lib/isc/result.c
index 8a9460b468..6f5f95dd8a 100644
--- a/lib/isc/result.c
+++ b/lib/isc/result.c
@@ -48,6 +48,7 @@ static char *text_table[ISC_R_LASTENTRY + 1] = {
 	"failure",				/* 25 */
 	"I/O error",				/* 26 */
 	"not implemented",			/* 27 */
+	"unbalanced parentheses",		/* 28 */
 };
 
 char *