"- both C and C++ have gone through quite some changes as well, and so have the compilers; so it's not exactly uncommon to find 20 year old code written without

"- both C and C++ have gone through quite some changes as well, and so have the compilers; so it's not exactly uncommon to find 20 year old code written without this in mind and making use of some specifics which now are unavailable" C, C++, and Fortran have ISO standards, and if you write standard-conforming code, the committees that revise standards are very careful not to break things. It's not like Python where the BDFL changes the syntax of the print statement.