*| struct HOSTENT {
*|   char FAR *       h_name;       0:4
*|   char FAR * FAR * h_aliases;    4:4
*|   short            h_addrtype;   8:2
*|   short            h_length;    10:2
*|   char FAR * FAR * h_addr_list; 12:4
*| }; total = 16 bytes
#DEFINE HOSTENT_SIZE  16
DO decl
 
IF Not InitWinsock()
    ? "WSAStartup failed"
    RETURN
ENDIF
 
LOCAL nHost, lcHOSTENT, lnNamePtr, lnAddrlistPtr
nHost = gethostbyname("microsoft.com")
 
IF nHost <> 0
    * copying data from the HOSTENT structure to a VFP string
    lcHOSTENT = GetMemBuf(nHost, HOSTENT_SIZE)
 
    * a pointer to the host name
    lnNamePtr = buf2dword(SUBSTR(lcHOSTENT, 1,4))
    ? "Host name:", GetMemStr(lnNamePtr)
 
    * a pointer to a null-terminated list of IP addresses
    lnAddrlistPtr = buf2dword(SUBSTR(lcHOSTENT, 13,4))
 
    * displaying IP addresses for this host
    = DisplayIPs(lnAddrlistPtr)
ELSE
* 10093 = WSANOTINITIALISED
* Either the application has not called WSAStartup, or WSAStartup failed
    ? "Error:", GetLastError()
ENDIF
= WSACleanup()
* End of Main
 
PROCEDURE  DisplayIPs (lnAddrlistPtr)
* retrieving IP addresses from the list
 
    LOCAL lnElementPtr, lnIPcount, lcDataAddress, lnDataAddress,;
        lcIPAddrBuf
 
    lnIPcount = 0  && list elements retrieved
    lnElementPtr = lnAddrlistPtr  && first member on the list
 
    * scanning the list one member by another
    * until a null member found
    DO WHILE .T.
        * the list member contains a DWORD memory address
        lcDataAddress = GetMemBuf(lnElementPtr, 4)
        lnDataAddress = buf2dword(lcDataAddress)
 
        IF lnDataAddress = 0
        * the last member on this list is null
            EXIT
        ENDIF
 
        * retrieving a DWORD with an IP address
        lcIPAddrBuf = GetMemBuf (lnDataAddress, 4)
 
        lnIPcount = lnIPcount + 1
        ? "IP " + LTRIM(STR(lnIPcount)) + ":",;
            inet_ntoa(buf2dword(lcIPAddrBuf))
 
        * shifting to the next element on the list
        lnElementPtr = lnElementPtr + 4   && DWORD
    ENDDO
RETURN
 
FUNCTION GetMemStr (lnAddr)
* returning data from a memory block as a VFP string
#DEFINE MEMSTR_BUFSIZE   128
    LOCAL lcBuffer
    lcBuffer = Repli(Chr(0), MEMSTR_BUFSIZE)
    = CopyMemory (@lcBuffer, lnAddr, MEMSTR_BUFSIZE)
RETURN SUBSTR(lcBuffer, 1, AT(Chr(0),lcBuffer)-1)
 
FUNCTION GetMemBuf (lnAddr, lnBufsize)
    LOCAL lcBuffer
    lcBuffer = Repli(Chr(0), lnBufsize)
    = CopyMemory (@lcBuffer, lnAddr, lnBufsize)
RETURN lcBuffer
 
FUNCTION InitWinsock()
#DEFINE WSADATA_SIZE 398
#DEFINE WS_VERSION 0x0202
    LOCAL lcWSADATA, lnInitResult
    lcWSADATA = Repli(Chr(0), WSADATA_SIZE)
    lnInitResult = WSAStartup (WS_VERSION, @lcWSADATA)
RETURN (lnInitResult = 0)
 
FUNCTION buf2dword(lcBuffer)
RETURN Asc(SUBSTR(lcBuffer, 1,1)) + ;
    BitLShift(Asc(SUBSTR(lcBuffer, 2,1)),  8) +;
    BitLShift(Asc(SUBSTR(lcBuffer, 3,1)), 16) +;
    BitLShift(Asc(SUBSTR(lcBuffer, 4,1)), 24)
 
PROCEDURE decl
    DECLARE INTEGER GetLastError IN kernel32
    DECLARE INTEGER WSAStartup IN ws2_32 INTEGER wVerRq, STRING @lpWSAData
    DECLARE INTEGER WSACleanup IN ws2_32
    DECLARE INTEGER gethostbyname IN ws2_32 STRING hostname
    DECLARE STRING inet_ntoa IN ws2_32 INTEGER in_addr
 
    DECLARE RtlMoveMemory IN kernel32 As CopyMemory;
        STRING @Dest, INTEGER Src, INTEGER nLength