winsock connect non-blocking

Socket中如何設置連接超時
（轉）Socket中如何設置連接超時
6.11 Connect with timeout (or another use for select() )

stack overflow
Non-blocking connect() with WinSocks
Making a Nonblocking socket for WinSocks and *nix

程式設計俱樂部 WinSock Connect

MSDN
ioctlsocket Function
select Function