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HANDLE WSAAsyncGetHostByAddr(
HWND hWnd,
unsigned int wMsg,
const char* addr,
int len,
int type,
char* buf,
int buflen
);
----

hWnd
-[in] Handle of the window that will receive a message when the asynchronous request completes.

wMsg
-[in] Message to be received when the asynchronous request completes.

addr
-[in] Pointer to the network address for the host. Host addresses are stored in network byte order.

len
-[in] Length of the address, in bytes.

type
-[in] Type of the address.

buf
-[out] Pointer to the data area to receive the hostent data. The data area must be larger than the size of a hostent structure because the data area is used by Windows Sockets to contain a hostent structure and all of the data referenced by members of the hostent structure. A buffer of MAXGETHOSTSTRUCT bytes is recommended.
buflen
-[in] Size of data area for the buf parameter, in bytes.