@itemize
@item
This function is missing on some platforms:
-NetBSD 3.0, OpenBSD 3.8, HP-UX 11.00, IRIX 6.5, Solaris 2.6, Cygwin, Interix 3.5, BeOS.
+NetBSD 3.0, OpenBSD 3.8, HP-UX 11.00, IRIX 6.5, Solaris 2.6, Cygwin 1.5.x,
+Interix 3.5, BeOS, Cygwin 1.7.
+@item
+This function exists, but does not support wide arguments on some
+platforms: Cygwin 1.5.x.
+@item
+On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
+accommodate all Unicode characters.
@end itemize