@item
This function is missing on some platforms:
OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11.23, IRIX 6.5, OSF/1 5.1, Solaris 9, mingw, MSVC 9, Interix 3.5, BeOS.
+@item
+On some platforms, this function fails to detect invalid fds with
+EBADF, but only if they lie beyond the current maximum open fd:
+FreeBSD 8.2.
@end itemize
Portability problems not fixed by Gnulib: