Blaise,
How about the attached? My goal is to have the usage be as similar to the
other PetscOptions... calls and too not require the Fortran user to be C aware
that is, they should not have to append null characters or declare special C
type declaration. In other words, the user writes Fortran77 code :-).[see
attached file: ex1f.F90]
I don't think it should bleed, but then I am no longer a Fortran
programmer.
Barry
On May 27, 2012, at 10:16 AM, Blaise Bourdin wrote:
> Barry,
>
> If I frame your email, will you sign it for me? ;)
>
> I am traveling so I did not have much time to do it, even in my sleep, but
> Tim's solution is essentially right.
>
> Have a look at the attached code. I had to write my own interface to
> PetscOptionsGetEnum, but I have to do the equivalent of FIXCHAR by myself
> (basically appending //C_NULL_CHAR). I checked in the debugger, and the list
> argument that is passed to PetscOptionsGetEList is the same as the one passed
> from C. Is this what you want?
>
> Do you want to do the FIXCHAR business in the C or fortran side? I suspect
> that you would prefer not having to append the C_NULL_CHAR in fortran, but I
> can't figure how to do that without allocating a new array of strings, and
> causing a memory leak. What do you think?
>
> If this is not what you want, could you meet me half way and write the
> fortran interface you would like to use, in which case I will try to write
> the missing fortran parts.
>
> Blaise
> <PetscF2003.F90>
>>
>> Tim,
>>
>> Thanks. But what I want is all bundled up a routine that takes in the
>> Fortran array of character strings and allocates and copies over them to the
>> C ptr business. Likely I could figure it out myself with but Blaise is such
>> a Fortran wizard he can do it optimally in his sleep :-)
>>
>> Barry
>>
>> On May 25, 2012, at 8:14 PM, Tim Gallagher wrote:
>>
>>> For what it's worth, I answered a question about how to pass string arrays
>>> awhile ago on StackOverflow:
>>>
>>> http://stackoverflow.com/questions/9686532/arrays-of-strings-in-fortran-c-bridges-using-iso-c-binding/9686741#9686741
>>>
>>> Tim
>>>
>>> ----- Original Message -----
>>> From: "Barry Smith" <bsmith at mcs.anl.gov>
>>> To: "For users of the development version of PETSc" <petsc-dev at
>>> mcs.anl.gov>
>>> Sent: Friday, May 25, 2012 8:57:52 PM
>>> Subject: Re: [petsc-dev] What needs to be done before a release?
>>>
>>> Blaise
>>>
>>> If you provide a fortran function to convert an array of Fortran strings to
>>> an array of C strings and tell us how to delete the result then we'll
>>> provide a PetscOptionsGetEnum() for Fortran.
>>>
>>> Barry
>>>
>>> On May 2, 2012, at 12:02 PM, Blaise Bourdin wrote:
>>>
>>>> Barry,
>>>>
>>>>>> Also, fortran wrappers over PetscOptionsEnum and PetscBagRegisterEnum
>>>>>> would be nice. I understand that it
>>>>>> is a bit tricky since it involves passing fortran arrays of strings.
>>>>>
>>>>> Yup. We'd be willing to support these from FORTRAN but someone else has
>>>>> to do the dirty work of figuring out how to handle those array of strings
>>>>> (maybe F2003?).
>>>>
>>>> I am attaching a simple proof of concept example that demonstrates how to
>>>> write a fortran interface and call petsc C functions from fortran using
>>>> F2003 C-interoperability instead of going through the fortran bindings.
>>>>
>>>> Don't be put off by all the warnings if you use gfortran. They would be
>>>> easy to avoid. Basically, right now, you detect the fortran integer and
>>>> real kinds that match that of the C ones. It would be quite simple to get
>>>> the fortran C-interoperable integer and real types associated with the C
>>>> type of PetscInt, PetscReal etc.
>>>>
>>>> Basically, we (I?) could write a fortran interface and a fortran function
>>>> for the tricky functions involving arrays of string, instead of creating a
>>>> custom binding in C. Are you willing to let some fortran pollution into
>>>> the petsc code? Where would these function have to be?
>>>>
>>>> Blaise
>>>>
>>>> PS: you need FCFLAGS='-ffixed-line-length-none -ffree-line-length-none
>>>> -ffree-form' or some subset of these to compile with gfortran. I'm not
>>>> sure why these are not the default with a file suffix .F90
>>>>
>>>> <PetscF2003Binding.F90>
>>>> --
>>>> Department of Mathematics and Center for Computation & Technology
>>>> Louisiana State University, Baton Rouge, LA 70803, USA
>>>> Tel. +1 (225) 578 1612, Fax +1 (225) 578 4276
>>>> http://www.math.lsu.edu/~bourdin
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>
> --
> Department of Mathematics and Center for Computation & Technology
> Louisiana State University, Baton Rouge, LA 70803, USA
> Tel. +1 (225) 578 1612, Fax +1 (225) 578 4276
> http://www.math.lsu.edu/~bourdin
>
>
>
>
>
>
>
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