manual/examples/isockad.c

   1 /* Internet Socket Example using sockaddr_in.
   2    Copyright (C) 1991-2024 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License
   6    as published by the Free Software Foundation; either version 2
   7    of the License, or (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <https://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <sys/socket.h>
  21 #include <netinet/in.h>
  22 #include <netdb.h>
  23
  24 void
  25 init_sockaddr (struct sockaddr_in *name,
  26                const char *hostname,
  27                uint16_t port)
  28 {
  29   struct hostent *hostinfo;
  30
  31   name->sin_family = AF_INET;
  32   name->sin_port = htons (port);
  33   hostinfo = gethostbyname (hostname);
  34   if (hostinfo == NULL)
  35     {
  36       fprintf (stderr, "Unknown host %s.\n", hostname);
  37       exit (EXIT_FAILURE);
  38     }
  39   name->sin_addr = *(struct in_addr *) hostinfo->h_addr;
  40 }