+@item
+This header file is missing on some platforms:
+mingw, BeOS.
+
+@item
+This header file is incomplete on some platforms:
+Cygwin 1.5.x, Haiku.
+
+@item
+This header file does not define @code{AI_ALL}, @code{AI_V4MAPPED},
+@code{AI_ADDRCONFIG} on some platforms:
+NetBSD 5.0.