Socket - connect problem: The descriptor is a file, not a socket

["Peter P. Mooring" <peterpm at xs4all dot nl>]

Hi all,

For a project I need a small program using a socket to communicate with a server so I downloaded and installed cygwin/gcc, got an example program from the net and compiled (and updated in.h and compiled again). No errors.

When I run the program (on Win98), see below, I get the message 'The descriptor is a file, not a socket'. I scanned the mailing lists , and the net, but am stuck.

Please help, thanks,

Peter

 

This is the program, I call it like this 'client 1685 164.139.146.156'

 

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <errno.h>
#include <ctype.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>

 

main(argc, argv)
 int argc;
 char *argv[];
 {
 
 struct hostent *hostp;
 struct servent *servp;
 struct sockaddr_in server;
 int sock;
 static struct timeval timeout = { 5, 0 };   /* five seconds */
 fd_set rmask, xmask, mask;
 char buf[BUFSIZ];
        int nfound, bytesread;

 

 if (argc != 3) {
  (void) fprintf(stderr,"usage: %s service host\n",argv[0]);
  exit(1);
 }
 if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
  perror("socket");
  exit(1);
 }
        if (isdigit(argv[1][0])) {
  static struct servent s;
  servp = &s;
  s.s_port = htons((u_short)atoi(argv[1]));
 } else if ((servp = getservbyname(argv[1], "tcp")) == 0) {
  fprintf(stderr,"%s: unknown service\n",argv[1]);
  exit(1);
 }
        if ((hostp = gethostbyname(argv[2])) == 0) {
  fprintf(stderr,"%s: unknown host\n",argv[2]);
  exit(1);
 }
 memset((void *) &server, 0, sizeof server);
 server.sin_family = AF_INET;
 memcpy((void *) &server.sin_addr, hostp->h_addr, hostp->h_length);
 server.sin_port = servp->s_port;
 if (connect(sock, (struct sockaddr *) &server, sizeof server) < 0) {
  (void) close(sock);
  perror("connect"); 
  exit(1);
 }
 FD_ZERO(&mask); 
 FD_SET(sock, &mask);
 FD_SET(fileno(stdin), &mask);
 for (;;) {
  rmask = mask;
  nfound = select(FD_SETSIZE, &rmask, (fd_set *)0, (fd_set *)0, &timeout);
  if (nfound < 0) {
   if (errno == EINTR) {
    printf("interrupted system call\n");
    continue;
   }
   /* something is very wrong! */
   perror("select");
   exit(1);
  }
  if (nfound == 0) {
   /* timer expired */
   printf("Please type something!\n");
   continue;
  }
  if (FD_ISSET(fileno(stdin), &rmask)) {
   /* data from keyboard */ 
   if (!fgets(buf, sizeof buf, stdin)) { 
    if (ferror(stdin)) {
     perror("stdin");
     exit(1);
    }
    exit(0);
   }
   if (write(sock, buf, strlen(buf)) < 0) {
    perror("write");
    exit(1);
   }
  }
  if (FD_ISSET(sock,&rmask)) {
   /* data from network */
   bytesread = read(sock, buf, sizeof buf);
   buf[bytesread] = '\0';
   printf("%s: got %d bytes: %s\n", argv[0], bytesread, buf);
  }
 }
} /* main - client.c */