+@item
+This function is missing on some platforms:
+Mac OS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 4.3.2, HP-UX 11,
+IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, MSVC 9, Interix 3.5, BeOS.
+@item
+This function is not declared (without @code{-D_GNU_SOURCE}) on some platforms:
+glibc 2.13.