In some earlier articles, we used the term freestanding. We said that a freestanding implementation is one that operates without the support of a hosted operating system. Think embedded systems, OS kernels, or bare-metal environments where heap allocation, system calls, and exception support are typically unavailable. The C++ standard defines a minimal subset of the language and library that must work in such constrained environments. But I wanted to go slightly deeper, because the term doesn’t come up much in everyday C++ — at least not until you start reading the standard more carefully or until you need to use such an implementation.