Re: [PATCH 1/3] compat: add qsort_s()

René Scharfe [off-list ref] writes:

quoted

You can hack around it by passing a wrapper callback that flips the
arguments. Since we have a "void *" data pointer, that would point to a
struct holding the "real" callback and chaining to the original data
pointer.

It does incur the cost of an extra level of indirection for each
comparison, though (not just for each qsort call).

Indeed.  We'd need a perf test to measure that overhead before we
could determine if that's a problem, though.

I agree.  Hopefully it won't be too much cost.

quoted

You could do it as zero-cost if you were willing to turn the comparison
function definition into a macro.

Ugh.  That either requires changing the signature of qsort_s() based
on the underlying native function as well, or using a void pointer to
pass the comparison function, no?  Let's not do that, at least not
without a good reason.

Let's not go there.  It may be zero runtime cost, but the cognitive
cost for people who need to code the comparison callback using the
macro is high.