php multi-thread

今天突然想看看PHP多线程的问题，发现很多人讲PHP的多线程其实是多进程，唉，破灭了！！！网上给PHP的模拟多线程提出了几种方案，下面仅摘录：

There are a few solutions, varying from "Hmmm, just about OK" through to "Poke out your eyes".

1. Write your multithreaded code as a PHP extension. Probably the most supported, but you need to write in C (or another language supported for extensions).
2. Spawn child processes onto the underlying OS, and read/write to their input/output with standard file handles. See popen for one route in, or PCNTRL. Reasonable, and you can use PHP from the command line.
3. Make other HTTP requests to yourself via CURL or similar, thus piggybacking on your web servers multi-processing capacity. Keeps all your code "web like", but runs the risk of irate support developers tracking you down and breaking thumbs.