[nthompson]

Very cool analysis.

I would add: A lot of regex work is still being done out of boost.regex; maybe people still haven't done the switch for most projects? For example, I think boost.regex is still used in Chrome.

Just ran your code on boost, looks like "shared_mutex" is the least used header there.

I use <future> all the time (in boost, no less) so it might be selection bias.

[Topolomancer]

Thank you! Do you want to share the results? I could add them to the git repository or include an addendum of the post.

[smitherfield]

Allegedly, the quality of STL <regex> implementations leaves much to be desired.

[alexhutcheson]

I default to using RE2[1] in most cases. If I really need backtracking, I would probably just use PCRE through the C++ wrapper[2], but that hasn't been a common need in my experience.

[1] https://github.com/google/re2/

[2] https://www.pcre.org/original/doc/html/pcrecpp.html