In the source code, what is the meaning of _ClassName_Method?

Questions
#1

Hello,

I have been looking through some of the source code, and I keep coming across methods that look like this:

sched { arg delta, item;
    _TempoClock_Sched
    ^this.primitiveFailed
}

What is the purpose of _TempoClock_Sched here? Generally speaking, what are these leading-underscore bits of code doing and why do these methods always return this.primitiveFailed? Is this documented somewhere?

#2

This indicates that the sc language is reaching into a primitive C++ implementation and SHOULD return something valid. If it does, the primitive failed error is returned.

#3

Thanks! I thought it might be something like that. I’ll have to brush up on my C++ before diving in further