What is the equivalent of a task in C? A thread, process, or something else? Do they share global variables? This question has likely been answered but I can't find it.

A task is an independently piece of running code inside a program. So its closest equivalent would be a light-weight thread. Threads share the same global variable space. You always have at least one task in your program called "main". You cannot pass variables to a task initialisation. Also, you must realise that functions in ROBOTC are not re-entrant, that means you can't call the same function from two tasks at the same time without mangling the variables. There is a mutex "API" though that will allow you to work around that.

- Xander