5 POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/rename.html}
9 Portability problems fixed by Gnulib:
12 This function does not work when the source file name ends in a slash on
16 This function will not replace an existing destination on some
21 Portability problems not fixed by Gnulib:
23 This function will not replace a destination that is currently opened