Tinyhttpd 知识点

1. fork 子进程

 #include <stdio.h>
 #include <unistd.h>

 int main(void)
 {
     pid_t pid;
     int count = ;
     pid = fork();
     while(){
         if(pid < )
             printf("error in fork");
         else if(pid == ){
             printf("i am the child process, my process id is %d\n",getpid());
             count ++;
             printf("count is:%d\n",count);
             sleep();
         }else{
             printf("i am the parent process,my process id is %d\n",getpid());
             printf("count is:%d\n",count);
             sleep();
         }
     }
     return ;
 }

运行结果:

i am the parent process,my process id is
count is:
i am the child process, my process id is
count is:

可以看出 子进程和 父进程之间的参数 count 不是同一个参数

├─sshd─┬─sshd───bash───pstree
        │      ├─sshd───bash───a.out───a.out
        │      └─sshd───bash

从pstree 指令中可以看出 a.out 之间的关系

[root@docker01 tinyhttpd_qf]# ps -ef|grep a.out
root           : pts/    :: ./a.out
root           : pts/    :: ./a.out
root           : pts/    :: grep --color=auto a.out

现在我把 a.out 子进程 kill 掉

发现只有 父进程在独自运行

 am the parent process,my process id is
count is:
i am the parent process,my process id is
count is:
i am the parent process,my process id is
count is:

重启 程序，然后先kill 父进程

发现只有子进程在 独立运行

 is:
i am the child process, my process id is
count is:
i am the child process, my process id is
count is:
i am the child process, my process id is
count is:
i am the child process, my process id is
count is:
i am the child process, my process id is