+/* Optional flags to influence mbswidth/mbsnwidth behavior. */
+
+/* If this bit is set, return -1 upon finding an invalid or incomplete
+ character. Otherwise, assume invalid characters have width 1. */
+#define MBSW_REJECT_INVALID 1
+
+/* If this bit is set, return -1 upon finding a non-printable character.
+ Otherwise, assume unprintable characters have width 0 if they are
+ control characters and 1 otherwise. */
+#define MBSW_REJECT_UNPRINTABLE 2
+
+/* Returns the number of screen columns needed for STRING. */
+#define mbswidth gnu_mbswidth /* avoid clash with UnixWare 7.1.1 function */
+extern int mbswidth (const char *string, int flags);
+
+/* Returns the number of screen columns needed for the NBYTES bytes
+ starting at BUF. */
+extern int mbsnwidth (const char *buf, size_t nbytes, int flags);