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@stek29 stek29/gethost.c
Created Aug 10, 2019

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get hostname by address on windows
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
// link with ws2_32.lib
#pragma comment(lib, "Ws2_32.lib")
int __cdecl main(int argc, char **argv)
{
//-----------------------------------------
// Declare and initialize variables
WSADATA wsaData = {0};
int iResult = 0;
DWORD dwRetval;
struct sockaddr_in saGNI;
char hostname[NI_MAXHOST];
char servInfo[NI_MAXSERV];
u_short port = 27015;
// Validate the parameters
if (argc != 2) {
printf("usage: %s IPv4 address\n", argv[0]);
printf(" to return hostname\n");
printf(" %s 127.0.0.1\n", argv[0]);
return 1;
}
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed: %d\n", iResult);
return 1;
}
//-----------------------------------------
// Set up sockaddr_in structure which is passed
// to the getnameinfo function
saGNI.sin_family = AF_INET;
saGNI.sin_addr.s_addr = inet_addr(argv[1]);
saGNI.sin_port = htons(port);
//-----------------------------------------
// Call getnameinfo
dwRetval = getnameinfo((struct sockaddr *) &saGNI,
sizeof (struct sockaddr),
hostname,
NI_MAXHOST, servInfo, NI_MAXSERV, NI_NUMERICSERV);
if (dwRetval != 0) {
printf("getnameinfo failed with error # %ld\n", WSAGetLastError());
return 1;
} else {
printf("getnameinfo returned hostname = %s\n", hostname);
return 0;
}
}
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