+@samp{F_DUPFD_CLOEXEC} is not defined on some platforms:
+MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11,
+IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.7.1, mingw, Interix 3.5,
+BeOS.
+
+@item
+@samp{AT_FDCWD}, @samp{AT_EACCESS}, @samp{AT_SYMLINK_NOFOLLOW},
+@samp{AT_SYMLINK_FOLLOW}, and @samp{AT_REMOVEDIR}
+are not defined on many platforms:
+glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
+5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 8, Cygwin 1.5.x, mingw, Interix 3.5, BeOS.