According to the README it supports most of C99, and even some things beyond that. It's not clearly defined what's meant with "most" or what's not supported, bu

According to the README it supports most of C99, and even some things beyond that. It's not clearly defined what's meant with "most" or what's not supported, but since I've never had any problems with any C99 code I've written I suspect it's mostly fairly little used stuff (complex numbers?), and it seems that for all practical purposes tcc supports C99 for almost all codebases.