Obviously you should be familiar with C. This entire conversation, however, is misguided by comparing it to Java or to fancy high-level languages. It's apples and oranges.

Of all of those, only C/C++ offers extremely high performance as its key feature. Being primarily a shorthand for assembly, C occupies a permanent place as the systems and performance language of choice and will remain there. If your application demands performance, use it. If not, then don't.