get_hostname.cpp

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>

#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>

#include <ace/OS.h>
#include <ace/SOCK_Connector.h>
#include <ace/SOCK_Stream.h>

#ifndef   NI_MAXHOST
#define   NI_MAXHOST 1025
#endif
 
int main(void)
{
    struct addrinfo * result;
    struct addrinfo * res;
    int error;
 
    char hostName[1024] = "";
    ACE_OS::hostname( hostName, sizeof hostName );
    struct hostent *hostnameResult = ACE_OS::gethostbyname( hostName );
    std::string name;
    if ( hostnameResult && hostnameResult->h_name )
      name = hostnameResult->h_name;
      
    std::cout << "name [" << name << "] hostname[" << hostName << "]" << std::endl;
    
    /* resolve the domain name into a list of addresses */
    error = getaddrinfo( hostName, NULL, NULL, &result );
 
    if (error != 0)
    {   
        fprintf(stderr, "error in getaddrinfo: %s\n", gai_strerror(error));
        return 1;
    }   
 
    /* loop over all returned results and do inverse lookup */
    for (res = result; res != NULL; res = res->ai_next)
    {   
        char hostname[NI_MAXHOST] = "";
 
        error = getnameinfo( res->ai_addr, res->ai_addrlen, hostname, NI_MAXHOST, NULL, 0, 0 ); 
	
 
        if ( error != 0 )
        {
            fprintf(stderr, "error in getnameinfo: %s\n", gai_strerror(error));
            continue;
        }
 
        if (*hostname)
        {
            printf("hostname: %s\n", hostname);
        }
 
    }   
 
    freeaddrinfo(result);
 
    return 0;
}