Hello,
I don't have anything to add to the threads topic itself, but was
triggered by something:
On Tue, 26 Nov 2024, Jonathan Wakely wrote:
> > > const size_t __bufsz = __deque_buf_size(sizeof(_Tp));
> > ...
> > I wonder why "const" is useful here.
>
> Because if you don't initialize a constant expression, then you get a
> runtime call to __deque_buf_size instead, which then has to be
> inlined.
Hmm? Are you saying there's a difference in inlining (or other)
behaviour between the two initializer lines in foo:
extern int bla(void);
int foo (void) {
const int x = bla();
int y = bla();
return x + y;
}
That would be surprising. Would it change if 'bla' was not a extern
function but something marked specially, constexpr or member function or
similar? But that would also be surprising to me.
I.e. ...
> Using the call to initialize a const size_t ensures it's a constant
> expression, and there's nothing for the inliner to do.
... why would a cv qualifier on the non-reference LHS of an initialization
put any constraints on the kind of expressions on the RHS?
Ciao,
Michael.
