#include
#include
int
main(void)
{
int n;
char line[MAXLINE];
int fd[2];
pid_t pid;
//create the pipe
if(pipe(fd)<0)
err_sys("pipe error!");
if((pid = fork()) < 0 ){
err_sys("fork error");
} else if (pid >0 ){ //parent
close(fd[0]); //close fd[0] read
sleep(5);
write(fd[1],"hello world\n",12); //write data into pipe
sleep(5);
write(fd[1],"dengfangwen\n\0",strlen("dengfangwen\n\0"));
} else { //child
close(fd[1]);//close fd[1] write
n = read(fd[0],line ,MAXLINE); //get data from pipe
write(STDOUT_FILENO, line ,n);
printf("child thread exec one times\n");
}
exit(0);
}
程序运行如下:
hello world;
child thread exec one times
dengfangwen
请问第三条的dengfangwen是怎么打印出来的?
sleep(5);
write(fd[1],"dengfangwen\n\0",strlen("dengfangwen\n\0"));
向管道写dengfangwen的时候,子进程应该已经退出了;