#include <sys/ioctl.h>
#include <net/if.h>
#include <arpa/inet.h>

char* GetLocalIp()  
{        
    int MAXINTERFACES=16;  
    char *ip = NULL;  
    int fd, intrface, retn = 0;    
    struct ifreq buf[MAXINTERFACES];    
    struct ifconf ifc;    

    if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) >= 0)    
    {    
        ifc.ifc_len = sizeof(buf);    
        ifc.ifc_buf = (caddr_t)buf;    
        if (!ioctl(fd, SIOCGIFCONF, (char *)&ifc))    
        {    
            intrface = ifc.ifc_len / sizeof(struct ifreq);    

            while (intrface-- > 0)    
            {    
                if (!(ioctl (fd, SIOCGIFADDR, (char *) &buf[intrface])))    
                {    
                    ip=(inet_ntoa(((struct sockaddr_in*)(&buf[intrface].ifr_addr))->sin_addr));    
                    break;  
                }                        
            }  
        }    
        close (fd);    
        return ip;    
    }  
}