13 May
2017
13 May
'17
6:35 p.m.
On 13 May 2017, at 13:20, Michael Kjörling <michael(a)kjorling.se> wrote:
Correct me if I am wrong, but _pass by value_ as opposed to _pass by
reference_ requires making a copy, no? That's the whole point, to
allow the callee to poke at the value it is given at will. At the very
least, it would require making a copy when a part of the passed value
is modified. Where is that memory going to come from, when even
malloc() isn't a part of the language but rather a part of the
standard library? Where is all that going to come from if you pass a
large array on a memory-constrained system of specs common back in the
days when C was designed, especially one that lacks virtual memory
support?
Are there languages that copy arrays in function calls defaultly? Perhaps Fortran has
some convention that allows that but I doubt it gets used very much, because it would be
insane in most cases: COMPUTE_MEAN_TEMPERATURE(ATMOS) is really *not* going to work very
well if it involves copying the ATMOS array.