That&#x27;s a bit unfair. The standard is from &#x27;99, but the implementation happened differently than c11 (which already had many bits implemented in clang before it was released).<p>In practice a lot of c99 got into gcc after 3.0 (2001) and it still took a bit of time for any distribution to include it as stable. If I remember correctly, lots of distributions held on to 2.9x for as long as possible. I&#x27;d say realistic c99 support has ~10 years now, rather than 17.