When running my PHP scripts in HHVM I see that I can pass a debug-host and debug-port arguments, but I can't seem to work out exactly what it does and how to use it.
Are those arguments for debugging HHVM itself (or maybe the compiled PHP itself) or is it for debugging the PHP script? That is to say, is it for debugging the way that HHVM works, or is it for debugging as I would normally do with XDebug, say?
At first I tried to connect it to my IDE that is set up for XDebug, but that doesn't seem to do anything so without going on a wild goose chase I thought I would ask here.
What are the debug arguments for HHVM for, exactly, and how can I use them to debug my PHP scripts in HHVM please?
Answer
Getting remote debugging working was fairly tricky and involved some gotchas and misunderstandings of the documentation.
You have to configure what they call as "sandbox" on the server side.
Then you have to use another instance of hhvm invoked with -m debug -h to attach the debugger to the running server. From there you can then use the full features of the debugger.
I wrote an article describing the process.