简单实现linux聊天室程序

花了很长时间用来练习掌握linux上socket的一个聊天室程序，可以实现的哦。
具体代码如下

代码一：

#ifndef _I_H
 
#define _I_H
 
#include 
#include 
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#include 
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#include 
#include 
#include 
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#include  
#include 
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#include 
#include 
 
#define SEVR_IP   "127.0.0.1"
#define SEVR_PORT  8081
#define CNTNT_LEN  150
#define MSG_LEN   sizeof(struct msg)
#define ADDR_LEN  sizeof(struct sockaddr)
#define USR_LEN   sizeof(struct user)
#define PRT_LEN   8
#define HSTR_LEN  sizeof(struct chat_history)
 
/* declare Global variables */
int mainfd;/* used as chat histroy file handle*/
int sockfd;/* used as socket local handle */
int count;
struct sockaddr_in server;
 
/* msg is used for communicating message */
struct msg
{
  int flag; /* flag meaning:1,ordinary; 2,log msg; 3,reg msg, other,file*/
  int id_from;
  int id_to;
  char content[CNTNT_LEN];
  char append[10]; 
};
 
/* user is used information list */
struct user
{
  int id;
  char name[10];
  char password[10];
  char *p_chatlog;
  struct sockaddr user_addr; 
};
/* chat_history used for reading chat history */
struct chat_history
{
  char content[CNTNT_LEN];
  char time[25];
  int to;
  int from;
  int count;
};
 
/* i_functions below is funtions needed by both client and sever */
extern int i_saveto_chat(struct msg *pmsg);
 
int i_clean_stdin ()
{
  while ('n' == getchar())
  {
    continue;
  }
 
  return(0);
}
 
int i_print(char *pmsg, int size)
{
  int i = 1;
 
  for (i; i<= size; i++)
  {
    if (*pmsg != 'n')
    {
      printf("%c", *pmsg);
      pmsg ++;
    }
    else
    {
      return(0);
    }
  }
 
  return(0);
}
int i_input(char *p_input)
{
  char c = '0';
  int i; 
 
  for (i = 0; i < CNTNT_LEN; i++)
  {
    p_input[i] = getchar();
    if (p_input[i] =='n')
    {
      return(0);   
    }    
  }
 
  printf("you have input long enough!n");
  return(0);
}
int i_socket(int domain, int type, int protocol)
{
  int fd; 
 
  if ((fd = socket(domain, type, protocol)) == -1)
  {
    perror("creat socket error:");
    exit(1);
  }
   
  return(fd); 
}
 
int i_bind(int fd, const struct sockaddr *addr, int namelen)
{
  if (-1 == bind(fd, addr, namelen))
  {
    perror("i_bind error:");
    exit(1);
  }
   
  return (0);
}
 
int i_recvfrom(int fd, void *buf, size_t len, int flags, 
    struct sockaddr *addr, int *size)
{  
  if (-1 == recvfrom(fd, buf, len, flags, addr, size))
  {
    perror("i_recvfrom error:");
    exit(1);  
  }
   
  return(0);
}
 
int i_sendto(int fd, void *buf, size_t len, int flags,
    struct sockaddr *addr, int size)
{
  if (-1 == sendto(fd, buf, len, flags, addr, size))
  {
    perror("i_sendto error");
    exit(1);  
  }
   
  return (0);
}
 
int i_open(const char *pathname, int flags)
{
  int fd;
  if ((fd = open(pathname, flags)) == -1)
  {
    perror("open_failed");
    exit(1);
  }
   
  return (fd);
}
int i_read(int fd, void *msg, int len)
{
  if(-1 == read(fd, msg, len))
  {
    perror("i_read error");
    exit(1);
  }
  return(0);
}
int i_write(int fd, void *msg, int len)
{
  if (-1 == write(fd, msg, len))
  {
    perror("i_write error");
    exit(0);
  }
  return(0);
}
 
/* init a socket,file and server addr */
int i_init()
{
  mainfd = i_open("./chat_log", O_RDWR|O_CREAT);
  sockfd = i_socket(AF_INET, SOCK_DGRAM, 0);
 
  /* initialize server address */
  bzero(&server, sizeof(server));
  server.sin_family = AF_INET;
  inet_pton(AF_INET, "127.0.0.1", &server.sin_addr);
  server.sin_port = htons(SEVR_PORT);
 
  perror("init");
   
  return (0);
}
 
char *i_get_time()
{
  time_t time_now;
  time(&time_now);
 
  return(ctime(&time_now));
}
int i_lseek(int fd, off_t size, int position)
{
  if (-1 == lseek(fd, size, position))
  {
    perror("seek error");
    exit(1);
  }
  return(0);
}
int i_saveto_chat(struct msg *pmsg)
{  
  struct chat_history hstr;
 
 
  bzero(&hstr, HSTR_LEN);
  count = count + 1;
  hstr.count =count;
  hstr.from = pmsg->id_from;
  hstr.to = pmsg->id_to;
  strncpy(hstr.content, pmsg->content, CNTNT_LEN);
  strncpy(hstr.time, i_get_time(), 25);
 
  i_lseek(mainfd, 0, SEEK_END);
 
  i_write(mainfd, &hstr, HSTR_LEN);
 
  return(0);
}
 
int i_print_history(int len, int i)
{
  struct chat_history chat_reader;
  int j;
  int position;
   
  bzero(&chat_reader, HSTR_LEN);
  if (i != 0)
  {
    position = len*i*HSTR_LEN;
    i_lseek(mainfd, position, SEEK_END);
  }
  else
  {
    position = len*i*HSTR_LEN;
 
    i_lseek(mainfd, HSTR_LEN, SEEK_SET);
  }
     
  for (j = 1; j <= len; j++)
  {
     
    i_read(mainfd, &chat_reader, HSTR_LEN);
    printf("n#item%d:id%dto id%d n", j,
      chat_reader.from, chat_reader.to);
    i_print(chat_reader.content, CNTNT_LEN);
    printf("n Time:%sn", chat_reader.time);
  }
 
  return(0);
}
 
#endif