lrslib is a self-contained ANSI C implementation of the reverse search algorithm for vertex enumeration/convex hull problems and comes with a choice of three arithmetic packages. Input file formats are compatible with Komei Fukuda's cdd package. All computations are done exactly in either multiple precision or fixed integer arithmetic. Output is not stored in memory, so even problems with very large output sizes can sometimes be solved. The program is intended for Unix/Linux platforms, but will compile using gcc/cygwin on Windows.