[CuriousSkeptic]

Not that familiar with c++ but used to have this thought about both Java and C#. Think I’ve changed my stance on it now though.

If following something like CQS the bifurcation can be thought of allowing “pure” functions and excluding code with a temporal / side-effecting component from higher order code.

Not saying bifurcating on void is the best approach to handle that, but in languages where side effects are a thing something is needed to make sure higher order code and side effecting code mix properly.

[masklinn]

This is only relevant to pure languages.

And this doesn’t come anywhere near to properly making that distinction anyway: a non-void function can have all the side effects, and a void function can have no side-effects.

It also does not “make sure higher order code and side effecting code mix properly”, it just makes a subset of likely side-effecting code not mix with higher order code at all.