对信号函数的从写来实现 setjmp 与 longjmp
------解决方案-------------------- SIGTSTP This interactive stop signal is generated by the terminal driver when we type the terminal suspend key (often Control-Z). This signal is sent to all processes in the foreground process group.
Unfortunately, the term stop has different meanings. When discussing job control and signals, we talk about stopping and continuing jobs. The terminal driver, however, has historically used the term stop to refer to stopping and starting the terminal output using the Control-S and Control-Q characters. Therefore, the terminal driver calls the character that generates the interactive stop signal the suspend character, not the stop character.