> historically you could compile C with the C++ compiler. not any C, only the C++-compatible subset. int* foo = malloc(sizeof(int)); has never worked in

> historically you could compile C with the C++ compiler. not any C, only the C++-compatible subset. int* foo = malloc(sizeof(int)); has never worked in C++ for instance while it's valid C. Code that worked is code that people actually did effort to express in a way compatible with a C++ compiler.