undocumented ai_flags value (0x80000000) in structure addrinfoex?

[Calvin]

Hi folks,

Does anybody knows this about the ai_flags value in the structure addrinfoex? The value 0x80000000 is not documented for ai_flags in MSDN.
I have following code:

==================================
ADDRINFOEX hints;
ADDRINFOEX *result = NULL;
ZeroMemory(&hints, sizeof(hints));
hints.ai_flags = AI_FQDN | AI_CANONNAME;
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
GetAddrInfoExW(L"www.google.com",
0,
NS_DNS,
0,
&hints,
&pResult,
0, 0, 0, 0);
==================================

the GetAddrInfoExW() succeed but in the returned pResult data structure, ai_flags equals to 0x80000000.
Does anyone know the meaning of 0x80000000? Why it returns 0x80000000?

Thanks a lot.
Calvin