Et sans tout le blabla,
je viens de le tester, ça marche !
/* REXX */
call addlib("rexxsupport.library", 0, -30, 0)
intui = showlist(l, "intuition.library",, a)
call forbid()
screen = next(intui, 56)
x = c2d(import(offset(screen, 12), 2)) /* Screen->Width */
y = c2d(import(offset(screen, 14), 2)) /* Screen->Height */
call permit();
say x "x" y
return