fork函数的相关知识和使用

pid_t fork(void)
功能：复制父进程来创建子进程
返回值：成功给父进程返回子进程PID，给子进程返回0，失败返回-1

#include<stdio.h>#include<unistd.h>#include<stdlib.h>int main(int argc, const char *argv[]){pid_t pid;pid = fork();if(pid < 0){perror("Fail to fork");//Fail to fork : 失败原因exit(-1);}//此时已经有两个进程if(pid == 0){printf("I am child process,fork return is %d,my pid is %d，my father pid is %d\n",pid,getpid(),getppid());}if(pid > 0){printf("I am father process,fork return is %d,my pid is %d\n",pid,getpid());}printf("Hello word!\n");return 0;}