gethostname(); gethostbyname(); gethostbyaddr() 的用法

#include <winsock2.h>

#include <stdio.h>

#pragma comment(lib, "ws2_32")

int main()

{

WSADATA wSdata;

if (WSAStartup(MAKEWORD(2,2), &wSdata)!=0)

{

printf("WSAStartup() error %d", GetLastError());

WSACleanup();

system("pause");

return -1;

}

char hname[100]={0};

char buff[20]={0};

struct in_addr addr;

gethostname(hname, sizeof(hname)); //获得主机名

printf("hostname: %s/n", hname);

//

printf("*************/n");

hostent *p=gethostbyname(hname);

printf("p->h_name:%s/n", p->h_name);

printf("p->h_length:%d/n", p->h_length);

printf("p->h_addrtype:%d/n", p->h_addrtype);

printf("p->h_aliases[0]:%s/n", p->h_aliases[0]);

int i=0;

while(p->h_addr_list[i])

{

addr.S_un.S_addr = *(unsigned long *)p->h_addr_list[i];

printf("p->h_addr_list[%d]:%s/n",i , inet_ntoa(addr));

i++;

}

i=0;

while(p->h_aliases[i])

{

printf("p->h_aliases[%d]:%s/n",i ,p->h_aliases[i]);

i++;

}

printf("*************/n");

//gethostbyaddr()

in_addr addrss;

addrss.S_un.S_addr = inet_addr("127.0.0.1");

p = gethostbyaddr((char *)&addrss, sizeof(in_addr), AF_INET);

printf("p->h_name:%s/n", p->h_name);

printf("p->h_length:%d/n", p->h_length);

printf("p->h_addrtype:%d/n", p->h_addrtype);

printf("p->h_aliases[0]:%s/n", p->h_aliases[0]);

i=0;

while(p->h_addr_list[i])

{

addr.S_un.S_addr = *(unsigned long *)p->h_addr_list[i];

printf("p->h_addr_list[%d]:%s/n",i , inet_ntoa(addr));

i++;

}

//

printf("*************/n");

p=gethostbyname("www.baidu.com");

printf("p->h_name:%s/n", p->h_name);

printf("p->h_length:%d/n", p->h_length);

printf("p->h_addrtype:%d/n", p->h_addrtype);

printf("p->h_aliases[0]:%s/n", p->h_aliases[0]);

i=0;

while(p->h_addr_list[i])

{

addr.S_un.S_addr = *(unsigned long *)p->h_addr_list[i];

printf("p->h_addr_list[%d]:%s/n",i ,inet_ntoa(addr));

i++;

}

i=0;

while(p->h_aliases[i])

{

printf("p->h_aliases[%d]:%s/n",i ,p->h_aliases[i]);

i++;

}

system("pause");

WSACleanup();

return 0;

}