Microsoft never planned to support C99 in the C compiler, they have been pretty clear about that for more than 15 years. GCC and Visual have a slightly differe

Microsoft never planned to support C99 in the C compiler, they have been pretty clear about that for more than 15 years. GCC and Visual have a slightly different release cycle. GCC can move the minor version whenever they please and they do. Microsoft only add language changes in a new major releases, and sometimes port it back in a visual studio update pack, which are more spaced in time. In both cases, the new release breaks the C++ ABI so updating is not something to be taken lightly. There is also the debate of what "implemented" means. GCC can be obtained in alpha and beta, so you can test new features early long before they are finished or included in a regular release. All things considered, MSVC is maybe one year later on the latest cool thing. Not much.