如何获得本机的IP地址？

[ljm]

用VC++编程，如何获得本机的IP地址？包括拨号上网的计算机和专线上网的计算机。

[xenogear]

gethostbyname
然后
inet_ntoa

[FlyingBoy_qhd]

先gethostname()

[mickey]

你可以用gethostname( )来获取本机IP!

[Firing_Sky]

来晚了 ^_^

[SoftDIY]

不算晚：）

Get hostname and ip address of local computer(2) in codeguru

--------------------------------------------------------------------------------
This article was contributed by Jaroslav Pisk .
Following is a code that gets local machine IP addresses. The advantages over the article by Jeff Lundgren are that my code recognises ALL IP addresses and is ready for IPv6 ;-)


char szHostName[128];

if( gethostname(szHostName, 128) == 0 )
{
// Get host adresses
struct hostent * pHost;
int i;

pHost = gethostbyname(szHostName);

for( i = 0; pHost!= NULL && pHost->h_addr_list[i]!= NULL; i++ )
{
CString str;
int j;

for( j = 0; j < pHost->h_length; j++ )
{
CString addr;

if( j > 0 )
str += ".";

addr.Format("%u", (unsigned int)((unsigned
char*)pHost->h_addr_list[i])[j]);
str += addr;
}
// str now contains one local IP address - do whatever you want to do with it (probably add it to a list)
}
}

[deepwater]

CString _GetLocalIP()
{
char szHostName[128];
CString str;

if( gethostname(szHostName, 128) == 0 )
{
// ホストのアドレスを取得する
struct hostent * pHost;
int i;

pHost = gethostbyname(szHostName);

for( i = 0; pHost!= NULL && pHost->h_addr_list[i]!= NULL; i++ )
{
int j;

for( j = 0; j < pHost->h_length; j++ )
{
CString addr;

if( j > 0 )
str += ".";

addr.Format("%u", (unsigned int)((unsigned
char*)pHost->h_addr_list[i])[j]);
str += addr;
}
}
}
return str;
}

[Sniper]

BYTE *p;
char temp[100];
struct hostent *hp;
char ip[16];

if(gethostname(temp, sizeof(temp))== 0)
{
if((hp =gethostbyname(temp))!=0)
{
p =(BYTE *)hp->h_addr;
wsprintf(ip, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
MessageBox(NULL, ip, "IP Address", MB_OK);
}
}

[tsc]

可以利用gethostname和gethostbyname获得本机的IP地址，，gethostbyname返回一HOSTENT机构的指针，HOSTENT机构定义如下：

struct hostent{
char FAR * h_name;
char FAR * FAR * h_aliases;
short h_addrtype;
short h_length;
char FAR * FAR * h_addr_list;
}
h_addr_list 是一个以空指针结尾的主机地址列表。下面是一个得到本机地址的函数 :

//
//得到本地的IP地址
//
unsigned long GetLocalAddr()
{
unsigned long broadcastIP = 0;

char bufName[20];
unsigned long * pLocalIP=NULL;
unsigned long subMask=0;
HOSTENT *pHost = NULL;

gethostname(bufName,20);
pHost = gethostbyname(bufName);
pLocalIP = (unsigned long *)pHost->h_addr_list[0];
return *pLocalIP;
}

[happywolf]

/*-----------------------------------------------------------
* 函数: GetHostID()
*
* 功能: 用下面的方法得到本机的机器名和IP地址,并分别放在两个参数中:
* 1. 调用gethostname()得到本机的机器名,试着用gethostbyname()
* 解析本机的IP地址
* 2. 如果上述方法失败,则采用下面的策略:
* - 创建一个 UDP socket
* - 连接 UDP socket 到任意一个指定的IP地址和端口
* - 调用 getsockname() 得到本机的IP地址
*-----------------------------------------------------------*/
void CSrvSocket::GetHostID (char* lpAddr,char* lpHostName)
{
char szLclHost [MAXHOSTNAME];
LPHOSTENT lpstHostent;
SOCKADDR_IN stLclAddr;
SOCKADDR_IN stRmtAddr;
int nAddrSize = sizeof(SOCKADDR);
SOCKET hSock;
int nRet;

/* 初始化本机地址*/
stLclAddr.sin_addr.s_addr = INADDR_ANY;

/* 得到本机的机器名 */
nRet = gethostname(szLclHost, MAXHOSTNAME);
if (nRet != SOCKET_ERROR)
{
/* 解析本机的IP地址*/
lpstHostent = gethostbyname((LPSTR)szLclHost);
if (lpstHostent)
{
stLclAddr.sin_addr.s_addr = *((u_long FAR*) (lpstHostent->h_addr));
}
}

/* 如果没有解析出来,采用第二种策略 */
if (stLclAddr.sin_addr.s_addr == INADDR_ANY)
{
/* 得到一个 UDP socket */
hSock = socket(AF_INET, SOCK_DGRAM, 0);
if (hSock != INVALID_SOCKET)
{
/* 连接到任意IP地址和端口 (NOT loopback) */
stRmtAddr.sin_family = AF_INET;
stRmtAddr.sin_port = htons(IPPORT_ECHO);
stRmtAddr.sin_addr.s_addr = inet_addr("128.127.50.1");
nRet = connect(hSock,
(LPSOCKADDR)&stRmtAddr,
sizeof(SOCKADDR));
if (nRet != SOCKET_ERROR)
{
/* 获取本机地址 */
getsockname(hSock,
(LPSOCKADDR)&stLclAddr,
(int FAR*)&nAddrSize);
}
closesocket(hSock);
}
}
strcpy(lpHostName,szLclHost);
strcpy(lpAddr,(inet_ntoa(stLclAddr.sin_addr)));
} /* GetHostID() *