The C23 edition of Modern C

Important reminder just in the Preface :-)

Takeaway #1: "C and C++ are different: don’t mix them, and don’t mix them up"

Specially relevant to all those folks that insist on "Coding C with a C++ compiler", instead of safer language constructs, and standard library alternatives provided by C++ during the last decades.

Perfectly valid to do if you need to interface with a large C code base and you just want to do some simple OO here and there. Especially if you cannot have runtime exceptions and the like.

This is how I managed to sneak C++ into an embedded C codebase. We even created some templates for data structures that supported static allocation at compile time.

What would be an example of "simple OO here and there" that cannot be done cleanly in plain C?

RAII

The killer feature of RAII is when combined with exceptions. But sneaking in exceptions in an embedded C project isn't something I'd encourage or recommend.

C++ imo doesn't offer anything compelling for the embedded usecase. Especially not considering all the footguns and politics it brings.

You can of course be strict and diligent about it but if you are you are pretty much just writing C anyway. Better to do it explicitly.

Allowing the use of the C++ standard library has been one of my biggest regrets (not that it was my decision to make, I fought it).

There are a lot of large C++ shops that purposefully disable exceptions and yet still use RAII usefully. It's so useful that in many C codebases you see people using RAII. For example Gtk has g_autoptr and g_autofree.

One of the most compelling things C++ offers to embedded use case is moving runtime initialization to compile-time initialization by liberally using constexpr functions. You literally ask the compiler to do work that would otherwise be done at runtime.