What is need to build native extension for Gems on Windows? (RubyGems)

More and more gems I run into requires building "native extensive", such as RedCloth. Are there tools that are open-source or free that is sufficient to do that? I heard MS Visual Studio also has a free version. Will that be开发者_如何学JAVA enough to build native extensions?

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If you installed Ruby with the RubyInstaller (as you should), then the DevKit has everything you need.

If you use the obsolete MSVC6 builds, then you need to install Microsoft Visual C++ 6.0, because newer versions of MSVC are incompatible. Good luck finding that, though, MSVC6 isn't even from this millenium.