This constraint requires the lengths of two line segments to differ by a constant. It can be useful to define the tolerances when making joints.
to add that license, and change all copyright notices to me, not Useful Subset, LLC. [git-p4: depot-paths = "//depot/solvespace/": change = 2211]
the documentation accordingly. Also rename the C example for consistency, and update copyright dates. [git-p4: depot-paths = "//depot/solvespace/": change = 2190]