This directory contains component macro .def files that are referenced by X-Macros in the ptpd source code. The component macros are used to define message, derived data types, and management TLV fields. The X-Macros are used to automatically generate most of the code used to pack, unpack, and free ptp data fields. Documentation on how to use X-Macros can be found at: http://en.wikibooks.org/wiki/C_Programming/Preprocessor#X-Macros