一个FORK（）调用的实验。通过建立共享内存区来实现进程之间的通信。父进程获取Fibonacci数列长度后，创建子进程来计算，待子进程完成后，父进程输出结果-A FORK () call experiment. Through the establishment of shared memory areas to achieve communication between the process. Parent process for the length of Fibonacci sequen