no idea if it'd be working against hardlinks (don't any OS that can do that :( ), but it sure does with symlinks :) .. it's written in Cwd docs:

The abs_path() function takes a single argument and returns the absolute pathname for that argument. It uses the same algorithm as getcwd(). (Actually, getcwd() is abs_path(".")) Symbolic links and relative-path components ("." and "..") are resolved to return the canonical pathname, just like realpath(3). Also callable as realpath().

... ofc, cause you mentioned it i've just tested it and seems to be working ok on linux and sunos.

--
AltBlue.