This is why I generally prefer event-driven programming over multithread programming. This is the sort of programming you do, for example, when you are implementing a GUI: you write short event handler functions that respond to events (such as mouse clicks or the completion of network or disk reads), and then a master loop receives events and dispatches the handler functions.
You get the same benefits as concurrency (maximum processor usage, at least when you only have one processor), but you avoid the pitfalls of shared memory, race conditions, and unexpected state changes (because only one event handler runs at a time). It does take a bit of getting used to (it seems so easy to make function calls like time() or mkdir() that are actually blocking and thus technically should be separated into a new callback function). But I find that the benefits of processor efficiency plus the comfort of avoiding concurrency problems are worthwhile.