We all know Linux is written in C. What you may not know is that it’s written in a long-outdated C dialect: The 1989 version of the C language standard, C89. This is also known as ANSI X3.159-1989, or ANSI C. Linus Torvalds has decided that enough is enough and will move Linux’s official C to 2011’s C11 standard.
This isn’t as big a transition as it may seem. C89 still has almost universal support. Because any C compiler is backward compatible with earlier versions, you won’t have any trouble compiling or running a C89 program. So, a C11 compliant compiler won’t have any trouble with any C89 legacy code.
So why bother? The change being made doesn’t include useful features that appear in newer versions.