/*
   select2.c: test time out using fd_set  variable
*/

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

#include <sys/select.h>

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

#define MAXSIZE 100

main(int argc, char *argv[])
{
   int s;			   /* s = socket */
   struct sockaddr_in in_addr;	   /* Structure used for bind() */
   struct sockaddr_in sock_addr;   /* Output structure from getsockname */
   struct sockaddr_in src_addr;    /* Used to receive (addr,port) of sender */
   int src_addr_len;		   /* Length of src_addr */
   int len;			   /* Length of result from getsockname */
   char line[MAXSIZE];

   if (argc == 1)
   { 
      printf("Usage: %s port\n", argv[0]);
      exit(1);
   }

   /* ---
      Create a socket
      --- */
   s = socket(AF_INET, SOCK_DGRAM, 0);

   /* ---
      Set up socket end-point info for binding
      --- */
   in_addr.sin_family = AF_INET;                   /* Protocol family */
   in_addr.sin_addr.s_addr = htonl(INADDR_ANY);    /* Wildcard IP address */
   in_addr.sin_port = htons(atoi(argv[1]));	   /* Use any UDP port */

   /* ---
      Here goes the binding...
      --- */
   if (bind(s, (struct sockaddr *)&in_addr, sizeof(in_addr)) == -1)
   {
      perror("bind: ");
      printf("- Note: this program can be run on any machine...\n");
      printf("        but you have to pick an unsed port#\n");
      exit(1);
   }
   else
   { 
      printf("OK: bind SUCCESS\n");
   }

   fd_set        recv_fds;          /* Recv file descriptors used by select */
   struct timeval timeout;          /* Time value for time out */

   FD_ZERO( &recv_fds );            // recv_fds = 00...0
   FD_SET( s, &recv_fds );          // Set bit s in recv_fds

   timeout.tv_sec = 5;		          /* Timeout = 5 sec + 0 micro sec*/
   timeout.tv_usec = 0;

   int result ;

   printf("Now use udp4-s3 and send a UDP message to port %s before %d sec !!!....\n", 
           argv[1], timeout.tv_sec );

   result =  select(FD_SETSIZE, &recv_fds, NULL, NULL, &timeout);
   printf("select( ) returns: %d\n", result);
}