https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117643
--- Comment #21 from anlauf at gcc dot gnu.org ---
(In reply to anlauf from comment #20)
Replying to myself:
> So if I come from the other side, which code to accept and which to diagnose,
> I tried:
>
> if (string->ts.type != BT_CHARACTER
> || string->ts.kind != 1
> || (string->expr_type == EXPR_VARIABLE && !string->ts.is_c_interop))
>
> and threw it on:
>
> subroutine sub1 (s)
> character(*), intent(in) :: s
> print *, f_c_string (s) ! detected
> print *, f_c_string (trim(s)) ! not detected
> end
>
> subroutine sub2 (s)
> character(kind=c_char,len=*), intent(in) :: s
> print *, f_c_string (s) ! OK
> print *, f_c_string (trim(s)) ! OK
> end
>
> I tried to extend to above conditions to
> .. (string->expr_type == EXPR_VARIABLE || string->expr_type ==
> EXPR_FUNCTION) ..
> but it appears that TRIM() keeps only the kind parameter, and when the
> argument
> is of kind C_CHAR the result string looses the interoperability attribute.
The latter issue is fixed by the following patch (obvious but not regtested):
diff --git a/gcc/fortran/iresolve.cc b/gcc/fortran/iresolve.cc
index 580f8c8407d..759eb99a645 100644
--- a/gcc/fortran/iresolve.cc
+++ b/gcc/fortran/iresolve.cc
@@ -3192,6 +3200,7 @@ gfc_resolve_trim (gfc_expr *f, gfc_expr *string)
{
f->ts.type = BT_CHARACTER;
f->ts.kind = string->ts.kind;
+ f->ts.is_c_interop = string->ts.is_c_interop;
f->value.function.name = gfc_get_string ("__trim_%d", string->ts.kind);
}
