On 13 September 2016 at 08:22, Markus Zimmermann <zimm...@gmail.com> wrote:
> On Monday, September 12, 2016 at 3:41:35 PM UTC+2, adon...@google.com
> wrote:
>>
>> unused constants and types cost nothing at run time. It's not that
>> simple, of course, because constant and type declarations may be the only
>> uses of an import of a package whose initialization has some cost; but this
>> is quite marginal.
>>
>
> The const declaration of my example is inside an unexported function body.
> It can not be accessed by an import. So, it should really matter only at
> compile time, right?
>
Right. The import case I was referring to is this:
import "p"
func main() {
const unused = p.K
}
The unused constant causes p to be an (unnecessary) dependency, which in
turn causes p.init to be executed.
However, I am referring to the definition of https://golang.org/doc/faq#
> unused_variables_and_imports which states "... Go refuses to compile
> programs with unused variables or imports, trading short-term convenience
> for long-term build speed and program clarity." Which holds true in the
> same way for an unused const as it does for an unused variable. However,
> even though it produces the same results, i.e. a new declaration which
> decreases the program clarity, only the variable declaration is marked.
>
You are right that the motivation given in the FAQ should apply equally to
constants and types.
Additionally, if an unused constant is compiled into the binary it does
> also matter to the binary size, even just a little bit.
An unused constant is unlikely to affect the size of the final executable
since in a typical compiler generates code or data for a constant only when
it is used. It will be present in the intermediate .a files though.
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
