\printlength{length} prints the value of a LaTeX length in the units specified by \uselengthunit{unit}, where unit may be any TeX length unit: pt, pc, in, mm, cm, bp, dd or cc). When the unit is pt, the printed length value will include any stretch or shrink; otherwise these are not printed. The unit argument may also be PT, in which case length values will be printed in point units but without any stretch or shrink values.