how can detect a php file is still running on apache? -

i have php script unlimited while, must run 24/7

1. in php file, how can check file running on server or stopped?
2. how can send signal apache stop , re-execute file?

i'm going assign numbers files. file running 24/7 the first file , file change state of first 1 called the second file. now, first file can write file or in database, let's say, every 10 minutes. way know if it's running checking file , last date when wrote file. create second file or database table , write in state want first file be. example: active or disabled. read file/table first file, if it's disabled, stop executing script.