This is a niche question, but I'm struggling to find a sufficient answer.
Struct members can be const, but can a function pointer/reference member be declared const? Based off my reading of C++17 section 9.3, I don't think so:
struct Ex {
const int i;
void (*pfn)(int i); // 1. can pfn be a const member?
void (&rfn)(int i); // 2. can rfn be a const member?
};
struct Ex {
const int i;
void (*const pfn)(int i); // 1. can pfn be a const member?
void (&rfn)(int i); // 2. can rfn be a const member?
};
void (const* pfn)(); is invalid syntax (what I tried), and 2) paranoia that the reference could be assigned to when without const. Thanks!
const qualifies the thing to its immediate left. The exception to the rule is that if const appear first, it applies to the thing to its immediate right. Most learn the exception to the rule (which is encountered quite common), and not the general rule (which causes lots of consternation when encountered).const" and by then I had already gotten used to the exception. We're using it at work now though, so perhaps I'll learn to use it without thinking in some distant future :-)type const * const * const ... but with more modern c++, we barely use pointers anymore, so the team pivoted to always put const on the lhs of the type