diff --git a/ChangeLog b/ChangeLog
index 62275a0408..3d55b79cbe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Apr 10 00:27:07 2003  Nobuyoshi Nakada  <nobu.nokada@softhome.net>
+
+	* time.c (time_strftime): RSTRING(format)->ptr might become NULL.
+
 Wed Apr  9 23:54:50 2003  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* variable.c (rb_obj_remove_instance_variable): better message.
diff --git a/time.c b/time.c
index f956d3154b..149f8eca8c 100644
--- a/time.c
+++ b/time.c
@@ -1279,7 +1279,7 @@ time_strftime(time, format)
     if (len == 0) {
 	rb_warning("strftime called with empty format string");
     }
-    if (strlen(fmt) < len) {
+    else if (strlen(fmt) < len) {
 	/* Ruby string may contain \0's. */
 	char *p = fmt, *pe = fmt + len;
 
@@ -1297,7 +1297,9 @@ time_strftime(time, format)
 	}
 	return str;
     }
-    len = rb_strftime(&buf, RSTRING(format)->ptr, &tobj->tm);
+    else {
+	len = rb_strftime(&buf, RSTRING(format)->ptr, &tobj->tm);
+    }
     str = rb_str_new(buf, len);
     if (buf != buffer) free(buf);
     return str;