获取IP（windows和linux）

#ifdef _WIN32
#include <winsock2.h>
#include <Ws2tcpip.h>
#pragma comment(lib,"ws2_32.lib")
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <arpa/inet.h>
#include <unistd.h>
#endif

sock = socket(AF_INET, SOCK_DGRAM, 0);
if(sock>=0)//!<0
{
if(bufcount>100)bufcount=100;
for(i=0;i<bufcount;i++)
{
sprintf(ifr.ifr_name,"eth%d",i);
if(ioctl(sock,SIOCGIFADDR,&ifr)<0) break;
::memcpy(&sin, &ifr.ifr_addr, sizeof(sin));
ipbuf[count++]=sin.sin_addr.s_addr;
}
close(sock);
}
#endif
return count;
}

int getselfiplist(unsigned long ipbuf[],int bufcount)
{
int i,count=0;
#ifdef _WIN32
char hostname[128];
struct hostent* inaddrs;
if(gethostname(hostname,128)==0)
{
inaddrs=gethostbyname(hostname);
if(inaddrs)
{
count=inaddrs->h_length/sizeof(in_addr);
if(count>bufcount)count=bufcount;
for(i=0;i<count;i++)
{
ipbuf=*(unsigned long*)inaddrs->h_addr_list;
}
}
}
#else
int sock;
struct sockaddr_in sin;
struct ifreq ifr;

sock = socket(AF_INET, SOCK_DGRAM, 0);
if(sock>=0)//!<0
{
if(bufcount>100)bufcount=100;
for(i=0;i<bufcount;i++)
{
sprintf(ifr.ifr_name,"eth%d",i);
if(ioctl(sock,SIOCGIFADDR,&ifr)<0) break;
::memcpy(&sin, &ifr.ifr_addr, sizeof(sin));
ipbuf[count++]=sin.sin_addr.s_addr;
}
close(sock);
}
#endif
return count;
}