Re: [Fortran-experiments] Bind(c) first experiences

["Christopher D. Rickett" <crickett at lanl dot gov>]

to make a further comment on my statement below, consider the following 
code:

module c_ptr_tests_3
use, intrinsic :: iso_c_binding

type, bind(c) :: my_f90_type
   integer(c_int) :: i
end type my_f90_type

contains
  subroutine sub0(c_struct) bind(c)
    type(c_ptr), value :: c_struct
    type(my_f90_type), pointer :: f90_type

    call c_f_pointer(c_struct, f90_type)
  end subroutine sub0

end module c_ptr_tests_3


currently, gfortran accepts this, and i think it is correct in doing so.  
in reading section 15.1.2.2 on C_F_POINTER, the FPTR param (second arg) 
"shall be a pointer.  It is an INTENT(OUT) argument."  Also, it says:

"(1)  If the value of CPTR is the C address of an interoperable data 
entity, FPTR shall be a data pointer with type and type parameters 
interoperable with the type of the entity..."

in the example i gave, i'm assuming c_struct is a struct that 
interops with my_f90_type.  according to the draft, in order for 
a derived type to be interoperable, it must have the BIND attribute 
(section 15.2.3, line 2).  i think it is correct for the pointer to a 
derived type to have the bind attribute, in some cases.  the pointer 
attribute should not be allowed for a derived type decl if it is a dummy 
arg to a bind(c) routine, i believe, but i'm not sure i'm checking this at 
the moment...  i'm also not verifying that the second arg has the POINTER 
attribute and has INTENT(OUT); i'll try and add these soon and submit a 
patch.  

thoughts?
Chris


On Tue, 16 Jan 2007, Christopher D. Rickett wrote:

> 
> 
> > Thirdly,
> >    type(c_funptr), pointer :: pnter
> > is accepted, whereas NAG f95 gives me an error:
> >    Error: test.f90, line 4: BIND(C) variable PNTER is a POINTER
> > (I think NAG's error message is a bit misleading.)
> > 
> > I think this is prohibited; see F2003, 15.2.2 / 15.2.3:
> > "C_PTR and C_FUNPTR shall be derived types with private components."
> > "C1505  (R429)  Each component of a derived type with the BIND attribute
> > shall be a nonpointer, nonallocatable data component with interoperable
> > type and type parameters."
> > 
> 
> i'm not sure whether the pnter declaration above should be prohibited or 
> not.  i believe it is just fine as long as it is not a dummy arg trying to 
> interop.  Tobias, what is the rest of the code?
> 
> Thanks.
> Chris
>