From: Goran on
On May 28, 10:05 am, Jesse Perla <jessepe...(a)> wrote:
> I have some functors that have more data that I might wish and
> algorithms that execute them (e.g. some weird multidimensional
> interpolators, etc.). I wrote some algorithms that accept these by
> constant reference, with the assumption that the function supplies a
> const operator(). i.e. stuff like:
> template<typename F> double f(const F& f)
> {
> return f(.1);
> };
> I realize that the std algorithms always pass functors by value. What
> is the reasoning for this with stateless algorithms like find
> predicates, transform, etc. (I can see why std::generate might want a
> copy by value)? Is it just to allow the functors to have a non-const
> operator()? Are there any other reasons, such as lack of inlining
> with modern compilers, that I can't pass const&?

One would guess that exactly if you pass a (const) reference, you'd
have a change to be inlined better.

I don't know the rationale behind pass-by-value (except that then, an
anon temp variable works even if parameter )

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