C/C++ Machine Learning Libraries for Clustering

What are some C/c++ Machine learning libraries that supports clustering of multi dimensional data? (for example K-Means)

So far I have come across

• SGI MLC++ http://www.sgi.com/tech/mlc/
• OpenCV MLL

I am tempted to roll-my-own, but I am sure pre-existing ones are far better performance optimized with more eyes on code.

From stackoverflow

• I am not sure if you are looking for algorithms like C4.5, ID3 etc or not. If you do, you can download the individual sources from university websites where they are actively researched.

  E.g: C4.5 Source can be found at Quinlan's website.

• The Open Source C Clustering Library from the Human Genome team at the University of Tokyo looks promising. It has K-means as well as other flat hierarchical clustering algorithms. Scroll down in their page for the bare library without the GUI. The Wikipedia-Clustering project seems nice and a bit lighter. Here's a specialized K-means library from The University of Mariland. I suggest you look at these considering your type of data. Preprocessing data to create feature vectors may be challenging.