Indeed it enforces some function calling convention, which may be an issue if you want to compile a high level language via C, particularly since C does not gua

Indeed it enforces some function calling convention, which may be an issue if you want to compile a high level language via C, particularly since C does not guarantee tail call optimization. Also there's no fast way to check arithmetic overflow from portable C, which limits bignum performance. Due to these limitations better portable assembly languages like C-- have been designed; these days LLVM bitcode is an option as well (which is not actually portable IIRC...).