netdir_getbyname()--Translate a Given Host-Service Pair

Syntax

 #include <netdir.h>

 int netdir_getbyname(struct netconfig *nconf,
                      struct nd_hostserv *service,
                      struct nd_addrlist **addrs);

  Service Program Name: QZNFTRPC

  Default Public Authority: *USE

  Threadsafe: No

The netdir_getbyname() function maps the host name and service name that are specified in the service parameter to a set of addresses that are consistent with the transport identified in the netconfig structure.

Parameters

nconf (Input): A pointer to a netconfig structure that is returned by either getnetconfig() or getnetconfigent().
service (Input): A pointer to a service name.
addrs (Output): A pointer to the addresses being returned.

Authorities

No authorization is required.

Return Value

0	netdir_getbyname() was successful.
-1	netdir_getbyname() was not successful. The nd_errno (defined in <netdir.h>) is set to indicate the error.

Error Conditions

If netdir_getbyname() is not successful, nd_errno usually indicates one of the following errors:

[ND_BADARG]	Bad argument passed.
[ND_NOHOST]	The host that was specified by the host name was not found.
[ND_NOMEM]	Not enough memory left.
[ND_NO_RECOVERY]	An unrecoverable error has occurred.
[ND_NOSERV]	Service name is unknown.
[ND_SYSTEM]	A damaged object was encountered. The damaged object cannot be used.
[ND_TRY_AGAIN]	The local server did not receive a response from an authoritative server. An attempt at a later time may succeed.

Error Messages

Message ID	Error Message Text
CPF9872 E	Program or service program &1 in library &2 ended. Reason code &3.

Usage Notes

netdir_getbyname() maps the host and service name to a set of addresses consistent with the transport specified in netconfig.

The caller is responsible to free the storage allocated by netdir_getbyname() by using the function netdir_free().

netdir_getbyname() does not support HOST_ANY or HOST_BROADCAST for host names specified in the nd_hostserv structure.

Example

See Code disclaimer information for information pertaining to code examples.

The following example shows how netdir_getbyname() is used:

#include <netdir.h>

main()
{
  void *handlep;                  /* A handle into network selection */
  struct netconfig *nconf;                  /* transport information */
  struct nd_hostserv nd_hostserv;    /* host and service information */
  struct nd_addrlist *nd_addrlistp;     /* addresses for the service */

  /* Initialize the network selection mechanism */
  if (handlep = setnetconfig()) == (void *)NULL)
  {
     exit(1);
  }

  /* Get the netconfig handle */
  if ((nconf = getnetconfig(handlep)) == (struct netconf *)NULL)
  {
     printf("Error in getting the netconfig handle.\n");
     exit(1);
  }

  /* Allocate memory for host and service names */
  nd_hostserv.h_host = (char *)malloc(24);
  nd_hostserv.h_serv = (char *)malloc(24);
  if ((nd_hostserv.h_host == (char *)NULL)
     || (nd_hostserv.h_serv == (char *)NULL))
   {
     printf("No memory available.  netdir_getbyname()
     failed.\n");
     exit(1);
   }

   printf("Enter the hostname:\n");
   scanf("%s", nd_hostserv.h_host);
   printf("Enter the service name:\n");
   scanf("%s", nd_hostserv.h_serv);

   /* Get the address for the service on the host on the
    * transport provider specified in the netconfig structure
    */
   if (netdir_getbyname(nconf, &nd_hostserv, &nd_addrlistp)
      != ND_OK)
   {
      printf("Cannot determine address for service\n");
      exit(1);
   }
   printf("The address of the <%s> service on host
          <%s> was found.\n", nd_hostserv.h_serv,
          nd_hostserv.h_host);

   /* Free the netdir structure allocated by netdir_getbyname() */
   netdir_free(nd_addrlistp, ND_ADDRLIST);

  /* Release the netconfig handle allocated by set setnetconfig() */
  endnetconfig(handlep);
}

API introduced: V4R2

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