The constant EXTRACTOR_VERSION is a hexadecimal representation of the version number of the installed libextractor header. The hexadecimal format is 0xAABBCCDD where AA is the major version (so far always 0), BB is the minor version, CC is the revision and DD the patch number. For example, for version 0.5.18, we would have AA=0, BB=5, CC=18 and DD=0. Minor releases such as 0.5.18a or significant changes in unreleased versions would be marked with DD=1 or higher.