Tells you exactly what and at which line the problem is?

Syntax error: unmatched thing in thing from std::nonstd::__map<_Cyrillic, _$$$dollars>const basic_string, __default_alloc_>

It's not as easy as it sounds, sometimes the screens are all wrong!! https://xkcd.com/722/

Sure, strtok is a terrible misfeature, a relic of ancient times, but it's plainly the heritage of C, not C++ (just like e.g. strcpy). The C++ problems are things like braced initialization list having different meaning depending on the set of available constructors, or the significantly non-zero cost of various abstractions, caused by strange backward-compatible limitations of the standard/ABI definitions, or the distinctness of vector etc.

Beware the DWIM!

In one notorious incident, Warren added a DWIM feature to the command interpreter used at Xerox PARC. One day another hacker there typed delete *$ to free up some disk space. (The editor there named backup files by appending $ to the original file name, so he was trying to delete any backup files left over from old editing sessions.) It happened that there weren't any editor backup files, so DWIM helpfully reported *$ not found, assuming you meant 'delete *'. It then started to delete all the files on the disk!

http://www.catb.org/jargon/html/D/DWIM.html

Syntax error: unmatched thing in thing from std::nonstd::__map<_Cyrillic, _$$$dollars>const basic_string< epic_mystery,mongoose_traits<char>, __default_alloc_<casual_Fridays = maybe>>

(from James Mickens' The Night Watch, highly recommended with his other essays: https://mickens.seas.harvard.edu/wisdom-james-mickens)

It will not "overflow". Signed integer overflow is undefined behavior. The compiler could remove the whole loop or do anything else imaginable (or not).

Access Teams? Do you need anything more than opening the Teams web app in a browser?

uMatrix browser extension. It has been marked archived by Gorhill, last release is two years old, you are supposed to just use uBlock [Origin]. However, it still (luckily) works fine and is exactly what I want. (Sure, I won't install this for my parents.) The GUI to simply choose what you want the site to be allowed to do is perfect.

There's a whole repo of possible methods: https://github.com/hakluke/how-to-exit-vim

That's against the terms of math :-)

Oh, and you can do that even in the official application? I thought it was impossible to be logged into multiple Teams accounts at the same time! (That was one of the reasons I was using Teas in a browser, being able to open another instance in a private window.) Or did they finally fix that, at least?