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

int main(int argc, char **argv) {
   unsigned short out_port = 35000;
   char * endptr;
   struct sockaddr_in server_address;
   int out_socket;
   int i=1;

   if( argc > 1 ) {
      out_port = (unsigned short) strtol(argv[1], &endptr, 10);
      errno = 0;
      if(errno != 0 || out_port == 0 || endptr == argv[1] ) {
         perror("Invalid port number");
         exit(1);
      }
   }
   printf( "Out port : %hu\n", out_port );
   fflush(NULL);

   memset( &server_address, 0, sizeof(struct sockaddr_in) );
   server_address.sin_family = AF_INET;
   server_address.sin_port = htons(out_port);
   if ( inet_pton( AF_INET, "127.0.0.1", &(server_address.sin_addr) ) <= 0 ) {
      perror("inet_pton error");
      exit(1);
   }

   if ( (out_socket = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
      perror("socket error");
      exit(1);
   }

   while (connect(out_socket, (struct sockaddr *) &server_address, sizeof(struct sockaddr_in)) < 0)
   {
      fprintf(stderr,"connect try %i failed : ",i);
      perror("");
      fflush(NULL);
      i++;
   }

   printf("Connection success : %i try\n",i);
   fflush(NULL);

   if( close(out_socket) < 0 ) {
      perror("close error");
      exit(1);
   }

   printf("Connection closed\n");
   fflush(NULL);

   fprintf(stderr,"last error : ");
   perror("");

   return 0;
}