What programming language is IIS written in?

I'd like to know this information for IIS versions开发者_JS百科 6.0, 7.0 and 7.5.

Probably C++, the core that is, newer versions such as 7 might have extensions written in other languages from the .NET family.

It is made in C++, microsoft has given isapi extension which is api for IIS and programmers can explore classes using this api