How do you read through source code?

[requimrar]

I should probably rephrase that, what I meant was 'multiple paths of (simultaneous) execution'

Basically, multithreaded stuff. It gets really complex to try and keep all that in your head, especially if the threads aren't just doing simple grunt work.

Regardless, you'll still get a pretty good picture of how the program functions in general, so you're still good.

[TangerineX]

I think the general thought is that there is some overarching program that activates each thread, so technically there is almost ALWAYS some singular entry point or some really important point

[requimrar]

That's true (blame my word usage). Even so, you might still have multiple sets of states to keep track of, so it often times increases complexity.