A basic definition and example and a few references for "X-Macros" is given in this wikipedia entry on the C pre-processor:

An X-Macro is a header file (commonly using a ".def" extension instead of the traditional ".h") that contains a list of similar macro calls (which can be referred to as "component macros").

What are some good sources of information on how to use this powerful technique? Are there well-known open source libraries using this method?

c include c-preprocessor
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