I agree with the point you're making, but you're actually wrong about C/C++. It's true that C/C++ compilers usually have a flag that gates language features. H

I agree with the point you're making, but you're actually wrong about C/C++. It's true that C/C++ compilers usually have a flag that gates language features. However, you're still using the same libc not matter which standard you've picked. For example, there were some changes made to format strings in C99, like parsing hexadecimal numbers with scanf. If you have a C99 libc, you'll always get that behavior, even if you specified "-std=c89".