  # The INPUT_FILTER tag can be used to specify a program that doxygen should # invoke to filter for each input file. Doxygen will invoke the filter program # by executing (via popen()) the command <filter> <input-file>, where <filter> # is the value of the INPUT_FILTER tag, and <input-file> is the name of an # input file. Doxygen will then use the output that the filter program writes # to standard output. 