Today, sure, but there's no assurance that this will be true in the future. If more compiler-friendly extensions are added to C++ to help it generate tighter, m

Today, sure, but there's no assurance that this will be true in the future. If more compiler-friendly extensions are added to C++ to help it generate tighter, more nimble machine code because it's given more leeway in optimizations, then the C++ code could be substantially smaller. C doesn't seem as interested in adopting some of the C++ paradigms that could make optimization better, tools like formalized iterators and such. There's been various attempts at pre-compiling the headers over the years, but the results have always been, for various reasons, less than perfect.