Overhead of Record Parameters
Posted: Mon Apr 15, 2019 2:47 am
What are the differences in the overhead when calling the procedures? I would assume they are minimal, in particular for P2 and P3, but also for P1, as the value record parameter is read-only, hence no value copying needs to take place (in the original PiO of 1992, the authors recommend using VAR parameters if performance is important -- and it was the same for Modula-2, IIRC -- but I would assume that's the (or a) reason for the read-only rule in the current language version).
Code: Select all
MODULE M10; TYPE P = POINTER TO R; R = RECORD END; VAR p: P; r: R; PROCEDURE P1(r: R); END P1; PROCEDURE P2(VAR r: R); END P2; PROCEDURE P3(p: P); END P3; BEGIN P1(r); P2(r); P3(p) END M10.