[petsc-dev] declaring argument as const basic type in PETSc

[Barry Smith]

On Aug 17, 2011, at 1:31 PM, Dmitry Karpeev wrote:

> That's just a typo on my part.
> I'm rewriting the whole SA ball of wax, but I can push a quicker fix
> for this too,

   What do you mean typo? I fixed the repository so that the declaration and the prototype match. You don't need to do anything. 

   But my question remains, should we const declare function arguments?

  barry

> but, unfortunately, I won't be able to do that untill next Monday.
> 
> 
> Dmitry.
> 
> On Wed, Aug 17, 2011 at 10:09 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> 
>>   Some declarations of the form
>> 
>> extern PetscErrorCode SAAddData(SA arr, const PetscInt len, const PetscInt *ia, const PetscScalar *wa, const PetscInt *ja);
>> 
>> have crept into PETSc.  const PetscInt len
>> 
>> Do we want to have such beasties? What purpose do they serve?
>> 
>> My understanding is that it is contaminating the entire code (because of the extern PetscErrorCode SAAddData(SA arr, const PetscInt len, const PetscInt *ia, const PetscScalar *wa, const PetscInt *ja); with the knowledge that internally the subroutine never changes the value of the stack variable function which is the opposite of encapsulation. What am I missing? Is this just stupid C syntax, is there a better way?
>> 
>>   Thanks
>> 
>>    Barry
>> 
>>