title: php multithreading problem
body: <p>I am writing a php cron job that reads thousands of feeds / web pages using curl and stores the content in a database. How do I restrict the number of threads to, lets say, 6? i.e., even though I need to scan thousands of feeds / web pages, I want only 6 curl threads active at any time so that my server and network don't get bogged down. I could do it easily in Java using wait, notify, notifyall methods of Object. Should I build my own semaphore or does php provide any built-in functions?</p>