-/* Change to directory I. If I is 0, change to the initial working
- directory; otherwise, I must be a value returned by chdir_arg. */
+/* Value suitable for use as the first argument to openat, and in
+ similar locations for fstatat, etc. This is an open file
+ descriptor, or AT_FDCWD if the working directory is current. It is
+ valid until the next invocation of chdir_do. */
+int chdir_fd = AT_FDCWD;
+
+/* Change to directory I, in a virtual way. This does not actually
+ invoke chdir; it merely sets chdir_fd to an int suitable as the
+ first argument for openat, etc. If I is 0, change to the initial
+ working directory; otherwise, I must be a value returned by
+ chdir_arg. */