https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117643
--- Comment #29 from anlauf at gcc dot gnu.org ---
(In reply to Jerry DeLisle from comment #28)
> --- snip ---
>
> > In iso-c-binding.def, one finds
> >
> > NAMED_CHARKNDCST (ISOCBINDING_CHAR, "c_char",gfc_default_character_kind)
> >
> > so kind('a') == kind(c_char_'a') on all targets.
>
> This implies that is_c_interop is a "don't care" if we check that type is
> character and the kind is gfc_default_character_kind all should work
> correctly.
>
> if (string->ts.type != BT_CHARACTER
> || (string->ts.type == BT_CHARACTER
> - && (string->ts.kind != 1 || string->ts.is_c_interop != 1)))
> + && (string->ts.kind != gfc_default_character_kind)))
> {
> gfc_error ("%qs argument of %qs intrinsic at %L shall have "
> "a type of CHARACTER(KIND=C_CHAR)",
>
> I have tested the above and all looks good to me.
This is great. Go ahead.
***
I frequently get confused by the details of interoperability.
Reading the standard text again:
F2023:18.3.1 Interoperability of intrinsic types
"Table 18.2 shows the interoperability between Fortran intrinsic types and C
types. A Fortran intrinsic type with particular type parameter values is
interoperable with a C type if the type and kind type parameter value are
listed in the table on the same row as that C type. ..."
I now read this as being compatible with having kind('a') == kind(c_char_'a')
on a particular processor (gfortran), and the above version of the check
then looks entirely correct.
(It is more complicated with interoperability of procedures (18.3.1), which
fortunately is not relevant here.)
