[petsc-dev] Fortran interface problem in v.3.10.2

[Adrian Croucher]

hi

Thanks to you both for looking into this.

It sounds like if we want type checking in the PETSc Fortran interfaces, 
which I agree is a useful thing, then no compilers are going to support 
passing in these derived types with type-bound procedures via type(*) 
interfaces anytime soon.

In my case the derived-type objects I'm passing in to 
SNESSetConvergenceTest() don't really need to have type-bound procedures 
(the derived type doesn't get subclassed, and there aren't really any 
data-hiding considerations), it's mostly just a style thing so that they 
work similarly to other derived types in the code. So I could fairly 
easily just turn the type-bound procedures into ordinary subroutines, 
not bound to any derived type.

That might be the simplest fix for me. I suppose this issue could still 
affect other people, but maybe not a lot of people are using PETSc with 
F2003.

- Adrian

On 23/10/18 2:55 AM, Martin Diehl wrote:
>>     I'm sorry, I don't understand. Are you saying that the example
>> code is not correct Fortran?
> In the case that your interface has a type(*) argument, it is not valid
> Fortran because 'context_type' contains the type-bound procedure
> 'context_init'. That is why the GNU compiler complains when the
> interface exists. Apparently, without the interface it accepts it, so
> not having an interface would be a solution in that case. However, the
> Intel compiler will fail during linking with or without interface, so
> it does not seem to be a general solution.
> At the moment, I believe that one simply has to live with the
> limitations that type(*) imposes on the data that can be passed to
> void*. To clarify this, I opened a thread in the Intel developer zone
> and will keep you updated
>
> https://software.intel.com/en-us/forums/intel-fortran-compiler-for-linux-and-mac-os-x/topic/798744
>
-- 
Dr Adrian Croucher
Senior Research Fellow
Department of Engineering Science
University of Auckland, New Zealand
email: a.croucher at auckland.ac.nz
tel: +64 (0)9 923 4611