1 files changed, 2 insertions, 1 deletions
diff --git a/types.c b/types.c
index 6f60f59..5707ce9 100644
--- a/types.c
+++ b/types.c
@@ -1405,10 +1405,11 @@ ucv_to_string_json_encoded(uc_stringbuf_t *pb, const char *s, size_t len, bool r
 			break;
 
 		default:
-			if (*s < 0x20)
+			if ((unsigned char)*s < 0x20)
 				ucv_stringbuf_printf(pb, "\\u%04x", (unsigned char)*s);
 			else
 				ucv_stringbuf_addstr(pb, s, 1);
+
 			break;
 		}
 	}