Yeah, it seems unlikely that the typical target machine would have either a word or cache line size that spilled a std::function via overhead on a realistic closure, but who knows, I would bet real money either way without a profile.

And I think it is less than ideal as concerns the fragile abd nascent revival of mainstream C++ to have this sort of a gang tackle over a nitpick like this. The approach is clearly fine because its how most every C program works.

The memes of C++ as too hard for the typical programmer and C++ programmers as pedantic know-it-all types are mostly undeserved, but threads like this I think reinforce those negative stereotypes.

The real S-Tier C++ people who are leading the charge on getting C++ back in the mindshare game (~ Herb Sutter's crew) are actively fighting both memes and I think it behooves all of us who want the ecosystem to thrive should follow their lead.

The danger of C++ becoming unimportant in the next five or ten years is zero, C and C++ are what the world runs on in important ways.

But in 20? 30? The top people are working with an urgency I haven't seen in decades and the work speaks for itself: 23 and 26 are coming together "chef's kiss" as Opus would say.

The world is a richer place with Rust and Zig in it, but it would be a poorer place with C++ gone, and that's been the long term trend until very recently.