diff --git a/tzfile.h b/tzfile.h
index 6054719..f01875a 100644
--- a/tzfile.h
+++ b/tzfile.h
@@ -25,12 +25,14 @@
 #endif
 
 struct tzinfo {
-	int	tz_timecnt;		/* Number of entries used */
-	long	tz_times[TZ_MAX_TIMES];	/* Saving Time transition times */
-	char	tz_types[TZ_MAX_TIMES];	/* Saving Time types for the above */
+	int		tz_timecnt;	/* Number of entries used */
+	long		tz_times[TZ_MAX_TIMES];
+					/* Saving Time transition times */
+	unsigned char	tz_types[TZ_MAX_TIMES];
+					/* Saving Time types for the above */
 	struct dsinfo {
-		long	ds_gmtoff;	/* Offset from GMT in seconds */
+		long	ds_gmtoff;		/* Offset from GMT in seconds */
 		char	ds_abbr[TZ_ABBR_LEN+1];	/* Time Zone abbreviation */
-		char	ds_isdst;	/* Used to fill tm_isdst */
+		char	ds_isdst;		/* Used to fill tm_isdst */
 	}	tz_dsinfo[TZ_MAX_TYPES];
 };