信号实验

1.　　研究kill命令，掌握通过kill命令发送信号的方法。

2.　　编写程序，通过定义信号处理函数来截获user消息。在消息处理函数中，设置标志变量，而主程序中通过系统调用pause（）等待消息，如果消息是user，则在终端窗口上显示信息。打开命令行窗口，运行这个程序。

3.　　打开另一个命令行窗口，通过ps命令获得2中程序的进程号，用kill命令给该进程发送user消息，观察其输出。

4.　　通过alarm函数给自己进程发送消息，每5秒钟一次，每接收到一次消息显示信息，10次后进程结束。

5. *编写程序，通过kill（）函数发送相同的消息，观察输出。

流程图：

-Signal in Experiment 1. Study the kill command master sends a signal via the kill command. 2 programming, user defined signal processing functions to intercept messages. Message processing function, set the flag variable, while the main program pause () system call to wait for further news, if the message is a user, the information displayed on the terminal window. Open a command line window and run this program. Open another command line window, by the ps command process No. 2 program, send the user a message to the process with the kill command to observe the output. By the alarm function to their own processes send messages once every 5 seconds, each received a message to display information to the end of the process 10 times.* Program, through the kill () function to send the same message, the observed output. Flowchart: