In C++, features like exceptions impact your whole program: you can either disable them in your whole program, or you need to deal with them throughout your code. As a famous article on C++ Report puts it:
Counter-intuitively, the hard part of coding exceptions is not the explicit throws and catches. The really hard part of using exceptions is to write all the intervening code in such a way that an arbitrary exception can propagate from its throw site to its handler, arriving safely and without damaging other parts of the program along the way.
Since even new throws exceptions, every function needs to provide basic exception safety — unless it only calls functions which guarantee throwing no exception — unless you disable exceptions altogether in your whole project.
Hence, exceptions are a "whole-program" or "whole-team" feature, since they must be understood by everybody in a team using them. But not all C++ features are like that, as far as I know.
A possible example is that if I don't get templates but I do not use them, I will still be able to write correct C++ — or will I not?. I can even call sort on an array of integers and enjoy its amazing speed advantage wrt. C's qsort (because no function pointer is called), without risking bugs — or not? It seems templates are not "whole-team".
Are there other C++ features which impact code not directly using them, and are hence "whole-team"? I am especially interested in features not present in C.
Update: I'm especially looking for features where there's no language-enforced sign you need to be aware of them. The first answer I got mentioned const-correctness, which is also whole-team, hence everybody needs to learn about it; however, AFAICS it will impact you only if you call a function which is marked const, and the compiler will prevent you from calling it on non-const objects, so you get something to google for. With exceptions, you don't even get that; moreover, they're always used as soon as you use new, hence exceptions are more "insidious". Since I can't phrase this as objectively, though, I will appreciate any whole-team feature.
Update 2: instead of C++ feature I should have written something like "C++-specific feature", to exclude things like multithreading which apply to a large amount of mainstream programming languages.
Appendix: Why this question is objective (if you wonder)
C++ is a complex language, so many projects or coding guides try to select "simple" C++ features, and many people try to include or exclude some ones according to mostly subjective criteria. Questions about that get rightfully closed regularly here on SO.
Above, instead, I defined (as precisely as possible) what a "whole-team" language feature is, provide an example (exceptions), together with extensive supporting evidence in the literature about C++, and ask for whole-team features in C++ beyond exceptions.
Whether you should use "whole-team" features, or whether that's a relevant concept, might be subjective — but that only means the importance of this question is subjective, like always.
Best Answer
I would nominate concurrency as a 'whole team' feature.
Although it is possible to design the software such that only a few experts need to be aware of concurrency issues and the rest of the team can reap the benefits without being concerned with the complexities (like you can do with templates), in practice it does not work that way. In practice, if you have multiple threads, then you have to analyse carefully for each and every variable you use if there are potential concurrency issues with that use.