On Friday, February 13th, 2026 at 12:44 PM, David Brown via Std-Proposals <std-proposals_at_[hidden]> wrote:

>
>
> On 13/02/2026 10:14, Simon Schröder via Std-Proposals wrote:
> >
> > Probably not the most elegant solution, but providing the tag as
> > template parameter would have zero runtime-overhead.
> >
>
> Yes, I have thought a lot about that.
>
> But what is missing there is that there is no way to control the use of
> a type.
>
> If we have a type "irq_disabled" with no public destructor, then the
> only way I can get a member of that type and pass it on to a restricted
> function is :
>
> irq_disabled irqs_off = disable_interrupts();
> modify_interrupt_table(irqs_off, new_interrupt_vector);
>
>
> With a template, you can write :
>
> using irqs_off = irq_disabled;
> modify_interrupt_table<irqs_off>(new_interrupt_vector);
>
> At no point are you forced to remember to call "disable_interrupts()".
> You might as well just encode the requirement in the function name
> (which is a well-established technique, but I hope to do better) :
>
> modify_interrupt_table_with_irqs_off(new_interrupt_vector);
>
>
> Even with non-type template parameters rather than type parameters, you
> can't (AFAICS) enforce the correct usage here.


You can do something like this: https://godbolt.org/z/5q3z33nve

It's hard to use that to revoke permissions instead of grant
permissions though.