Re: [patch,fortran] Support type real for count_rate in system_clock (PR28484)

[Paul Brook <paul at codesourcery dot com>]

> > Should one also implement
> >    system_clock(int4, int8, int16)
> > that is: Mixing all different integer kinds for system_clock? Currently,
> > the integer have to be all of the same kind.
> > Doing so gives then in total 3*3*3 = 27 integer and 4*3*3 = 36
> > real/integer combinations, i.e. 63 combinations!
>
> One could emit the necessary type conversions, i.e. only implement
>   system_clock (int4, int4, int4)
> in the library and then convert the parameters appropriately for all
> other combinations, e.g. translating
>   system_clock (int4, int8, int16)
> as
>   int4 t1 = int8
>   int4 t2 = int16
>   system_clock (int4, t1, t2)
>   int8 = t1
>   int16 = t2
> (I don't know the semantics of system_clock off the top of my head,
> the sensible sequence and choice of types depends on the INTENTs and
> the possible values of the arguments)

I think this is definitely the way to go. 
IMHO trying to enumerate all the possible combinations of argument types and 
provide library functions for them is a bad idea. It's feasible (and 
sometimes necessary) for functions with only a single argument type, but not 
when multiple types are involved.

Paul