@item
This function does not support the error values that are specified by POSIX
but not defined by the system, on some platforms:
-OpenBSD 4.0, OSF/1 5.1, Cygwin, mingw.
+OpenBSD 4.0, OSF/1 5.1, Cygwin 1.5.x, mingw.
@end itemize
Portability problems not fixed by Gnulib: