The fchdir() function shall be equivalent to chdir() except that
the directory that is to be the new current working directory is specified by
the file descriptor fildes.
A conforming application can obtain a file descriptor for a file of type
directory using open(), provided that the file status flags and access
modes do not contain O_WRONLY or O_RDWR.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html