Is PHP unsuitable for HTML5 WebSockets?

I've looked all over the net and I have been unable to find a concrete answer to this question. I am about to start development on a web application that will need to provide real-time updates of data to user's browsers. WebSockets are ideal for this task. I have read in some places on the net that PHP is not suitable for WebSockets due to it's nature. That WebSockets are designed for long running threads/processes which each maintain multiple event-driven connections, whereas PHP was designed around the short-lived single process procedural paradigm. Yet on the other hand I see lots of guides and libraries (such as http://socketo.me/) on the net that deal with PHP WebSockets. So I don't know what to think at this stage. Is PHP a suitable platform for developing a web application that requires WebSockets?