Introduction - If you have any usage issues, please Google them yourself
Create two processes, allowing the child to read a file, read the parent process waits for the child process to continue execution after the file, realize the process of working together. Processes work together to coordinate the two processes is to make arrangements for implementation of the order and thus can be used to wait for the function to achieve this. When you need to wait for the child process end of the run, you can call the parent process to wait for the function.