client.c

linux环境下实现客户端与服务器端通信.

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/fcntl.h>
#include <string.h>
#define SERVER_PORT 5432
#define MAX_LINE 256
#include <stdlib.h>
int  main(int argc, char * argv[])
{
  FILE *fp;
  struct hostent *hp;
  struct sockaddr_in sin;
  char *host;
  char buf[MAX_LINE];
  int s;
  int len;
  if (argc==2) {
    host = argv[1];
  }
  else {
    fprintf(stderr, "usage: simplex-talk host\n");
    exit(1);
  }

  /* translate host name into peer’s IP address */

  hp = gethostbyname(host);
  if (!hp) {
    fprintf(stderr, "simplex-talk: unknown host: %s\n", host);
  exit(1);

  }

  /* build address data structure */
  bzero((char *)&sin, sizeof(sin));
  sin.sin_family = AF_INET;
  bcopy(hp->h_addr, (char *)&sin.sin_addr, hp->h_length);
  sin.sin_port = htons(SERVER_PORT);

  /* active open */
  if ((s = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
    perror("simplex-talk: socket");
    exit(1);
  }
  if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
    perror("simplex-talk: connect");
    close(s);
    exit(1);
  }
  /* main loop: get and send lines of text */
  while (fgets(buf, sizeof(buf), stdin)) {

    buf[MAX_LINE-1] = '\0';
    len = strlen(buf) + 1;
    send(s, buf, len, 0);
  }
}