/*---------------------------------------------------------------------+
|                Copyright (c) 1995, SAS Institute Inc.                |
|                  Unpublished - All Rights Reserved                   |
|                      S A S / C   S A M P L E                         |
|                                                                      |
|         NAME: GHBNM                                                  |
|     LANGUAGE: C                                                      |
|      PURPOSE: This program uses the socket call, gethostbyname()     |
|               to return an IP address which corresponds to the       |
|               supplied hostname. gethostbyname() will determine if   |
|               a nameserver or local host tables are being used for   |
|               name resolution. The answer is returned in the         |
|               hostent structure, "hp" and then printed.              |
|               Additional details on this socket function may be      |
|               found in the SAS/C Library Reference Vol 2, Third      |
|               Edition, Release 6.00.                                 |
|        NOTES: The local host must be properly configured for name    |
|               resolution via either a nameserver or host tables.     |
|   MVS -                                                              |
|      COMPILE, LINK, EXECUTE: SUBMIT prefix.SAMPLE.AUX(LC370CLG)      |
|        NOTES: "prefix" is the SAS/C installation defined high-level  |
|               qualifier.                                             |
|        NOTES: on the EXEC statement add a: ,PARM.GO='your.host.name' |
|               to pass a hostname value as the first parameter to the |
|               program.                                               |
|   TSO -                                                              |
|      COMPILE: LC370 CLIST                                            |
|         LINK: CLK370 CLIST                                           |
|      EXECUTE: CALL 'your.load.lib(GHBNM)' 'your.host.name'           |
|   CMS -                                                              |
|      COMPILE: LC370                                                  |
|         LINK: CLINK GHBNM (GENMOD                                    |
|      EXECUTE: GHBNM your.host.name                                   |
+---------------------------------------------------------------------*/

#include <sys/types.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>

main(int argc, char *argv[])
{
struct hostent *hp;
struct in_addr ip_addr;

/*---------------------------------------------------------------------+
| Verify a "host_name" parameter was supplied.                         |
+---------------------------------------------------------------------*/
if (argc < 2 || *argv[1] == '\0')
   {
   printf("host_name parameter was not supplied, exiting.\n");
   exit(EXIT_FAILURE);
   }

/*---------------------------------------------------------------------+
| call gethostbyname() with a host name. gethostbyname() returns a     |
| pointer to a hostent struct or NULL.                                 |
+---------------------------------------------------------------------*/
hp = gethostbyname(argv[1]);

if (!hp)
   {
   printf("%s was not resolved\n",argv[1]);
   exit(EXIT_FAILURE);
   }

/*---------------------------------------------------------------------+
| move h_addr to ip_addr. This enables conversion to a form suitable   |
| for printing with the inet_ntoa() function.                          |
+---------------------------------------------------------------------*/
ip_addr = *(struct in_addr *)(hp->h_addr);
printf("Hostname: %s, was resolved to: %s\n",
                                 argv[1],inet_ntoa(ip_addr));


exit(EXIT_SUCCESS);
}