[技術] Linux具名管線(FIFOs)編程

Written on 8:39 下午 by Yu Lai

From: http://blog.csdn.net/lcrystal623/archive/2007/03/16/1531201.aspx

具名管線可以用於任何兩個程序間通信，因為有名字可引用。注意管道都是單向的，因此雙方通信需要兩個管道。

下面分別是這兩個程式代碼,同樣是Lucy先運行,然後是Peter。

fifoLucy.c

#include <sys/types.h>
#include <sys/stat.h>

#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>

int main()
{
 char write_fifo_name[] = "lucy";
   char read_fifo_name[] = "peter";
   int write_fd, read_fd;
   char buf[256];
   int len;
   struct stat stat_buf;

   int ret = mkfifo(write_fifo_name, S_IRUSR | S_IWUSR);
   if( ret == -1) 
 {
    printf("Fail to create FIFO %s: %s",write_fifo_name,strerror(errno));
      exit(-1);
        }

   write_fd = open(write_fifo_name, O_WRONLY);
   if(write_fd == -1) 
 {
    printf("Fail to open FIFO %s: %s",write_fifo_name,strerror(errno));
      exit(-1);
        }
        
   while((read_fd = open(read_fifo_name,O_RDONLY)) == -1) 
 {
    sleep(1);
        }
      
 while(1) 
 {
      printf("Lucy: ");
    fgets(buf, 256, stdin);
      buf[strlen(buf)-1] = '\0';
      if(strncmp(buf,"quit", 4) == 0) 
  {
         close(write_fd);
         unlink(write_fifo_name);
         close(read_fd);
         exit(0);
                }
      write(write_fd, buf, strlen(buf));
      len = read(read_fd, buf, 256);
      if( len > 0) 
  {
       buf[len] = '\0';
         printf("Peter: %s\n", buf);
                }
        }
}

fifoPeter.c

#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>

int main(void)
{
 char write_fifo_name[] = "peter";
   char read_fifo_name[] = "lucy";
   int write_fd, read_fd;
   char buf[256];
   int len;

   int ret = mkfifo(write_fifo_name, S_IRUSR | S_IWUSR);
   if( ret == -1) 
 {
    printf("Fail to create FIFO %s: %s",write_fifo_name,strerror(errno));
    exit(-1);
    }

   while((read_fd = open(read_fifo_name, O_RDONLY)) == -1) 
 {
  sleep(1);
        }
        
   write_fd = open(write_fifo_name, O_WRONLY);
   if(write_fd == -1) 
 {
    printf("Fail to open FIFO %s: %s", write_fifo_name, strerror(errno));
      exit(-1);
        }

   while(1) 
 {
      len = read(read_fd, buf, 256);
      if(len > 0) 
  {
       buf[len] = '\0';
         printf("Lucy: %s\n",buf);
                }
      printf("Peter: ");
      fgets(buf, 256, stdin);
      buf[strlen(buf)-1] = '\0';
      if(strncmp(buf,"quit", 4) == 0) 
  {
       close(write_fd);
       unlink(write_fifo_name);
         close(read_fd);
         exit(0);
                }
      write(write_fd, buf, strlen(buf));
        }
}

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