1 #include <winsock2.h> 2 #include <ws2tcpip.h> 3 #include <stdio.h> 4 #include <windows.h> 5 #pragma comment(lib, "ws2_32.lib") 6  7 int main(int argc, char **argv) 8 { 9 10     //-----------------------------------------11     // Declare and initialize variables12     WSADATA wsaData;13     int iResult;14 15     DWORD dwError;16     int i = 0;17 18     struct hostent *remoteHost;19     char *host_name;20     struct in_addr addr;21 22     char **pAlias;23     iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);24     if (iResult != 0) {25         printf("WSAStartup failed: %d\n", iResult);26         return 1;27     }28 29     host_name = new char[100];30     int index = gethostname(host_name,strlen(host_name));31     if (0 != index)32     {33         printf("Error\n");34     }35 36     printf("Calling gethostbyname with %s\n", host_name);37     remoteHost = gethostbyname(host_name);38 39     if (remoteHost == NULL) {40         dwError = WSAGetLastError();41         if (dwError != 0) {42             if (dwError == WSAHOST_NOT_FOUND) {43                 printf("Host not found\n");44                 return 1;45             } else if (dwError == WSANO_DATA) {46                 printf("No data record found\n");47                 return 1;48             } else {49                 printf("Function failed with error: %ld\n", dwError);50                 return 1;51             }52         }53     } else {54         printf("Function returned:\n");55         printf("\tOfficial name: %s\n", remoteHost->h_name);56         for (pAlias = remoteHost->h_aliases; *pAlias != 0; pAlias++) {57             printf("\tAlternate name #%d: %s\n", ++i, *pAlias);58         }59         printf("\tAddress type: ");60         switch (remoteHost->h_addrtype) {61         case AF_INET:62             printf("AF_INET\n");63             break;64         case AF_NETBIOS:65             printf("AF_NETBIOS\n");66             break;67         default:68             printf(" %d\n", remoteHost->h_addrtype);69             break;70         }71         printf("\tAddress length: %d\n", remoteHost->h_length);72 73         i = 0;74         if (remoteHost->h_addrtype == AF_INET)75         {76             while (remoteHost->h_addr_list[i] != 0) {77                 addr.s_addr = *(u_long *) remoteHost->h_addr_list[i++];78                 printf("\tIP Address #%d: %s\n", i, inet_ntoa(addr));79             }80         }81         else if (remoteHost->h_addrtype == AF_NETBIOS)82         {   83             printf("NETBIOS address was returned\n");84         }   85     }86 87     return 0;88 }