linux 匿名管道实例详解

#include<stdio.h> 
#include<unistd.h> 
#include<string.h> 
#include<stdlib.h> 
 
int main() 
{ 
  int _pipe[2]; 
  int ret = pipe(_pipe); 
  if (ret < 0) 
  { 
    perror("pipe"); 
    return 1; 
  } 
  pid_t id = fork (); 
  if (id<0) 
  { 
    perror("fork"); 
    return 2; 
  } 
  else if (id == 0) 
  { 
    // child 
    int count =5; 
    close (_pipe[0]); 
    char* msg = "hello bit"; 
    while (count --) 
    { 
      write(_pipe[1],msg,strlen(msg)); 
      sleep(1); 
    } 
    close (_pipe[1]); 
    exit(123); 
  } 
  else  
  { 
    // Father 
    close(_pipe[1]); 
    char buf[128]; 
    while(1) 
    { 
      int count =5; 
      ssize_t s = read ( _pipe[0],buf,sizeof(buf)-1); 
      if (s<0) 
      { 
        perror("read"); 
      } 
      else if(s==0) 
      { 
        printf("write is close\n"); 
        return 2; 
      } 
      else 
      { 
        buf[s] ='\0'; 
        printf ("child >> father: %s\n",buf); 
      } 
      count --; 
      if (count == 0) 
      { 
        close (_pipe[0]); 
        break; 
      } 
    } 
     
    int status = 0; 
    pid_t _wait = waitpid (id, &status,0); 
    if (_wait > 0) 
    { 
      printf("exit code is %d, signal is %d\n", 
          WIFEXITED(status), status & 0xff); 
    } 
 
    } 
     
  return 0; 
}