[petsc-users] Inquiry about the c++ destructor and PetscFinalize.

[neil liu]

Thanks a lot, Constantine. It works pretty well.



On Fri, Jun 16, 2023 at 6:52 PM Constantine Khrulev <ckhroulev at alaska.edu>
wrote:

> In your code the destructor of DMManage is called at the end of scope,
> i.e. after the PetscFinalize() call.
>
> You should be able to avoid this error by putting "DMManage objDMManage"
> in a code block to limit its scope and ensure that it is destroyed
> before PETSc is finalized:
>
> int main(int argc, char** argv) {
>    PetscFunctionBeginUser;
>    PetscCall(PetscInitialize(&argc, &argv, NULL, help));
>
>    {
>      DMManage objDMManage;
>     } // objDMManage is destroyed here
>
>    PetscFinalize();
>    return 0;
> }
>
> On 6/16/23 14:13, neil liu wrote:
> > Dear Petsc developers,
> >
> > I am trying to use Petsc with C++. And came across one issue.
> > Class DMManage has been defined, one default constructor and
> > destructor has been defined there.
> > The code has a runtime error, "double free or corruption". Finally I
> > found that, this is due to PetscFinalize. If I called explicitly the
> > destructor before this PetscFinalze, the error will disappear.
> >
> > Does that mean PetscFinalize do some work to destroy DM?
> >
> > Thanks,
> >
> > #include <petscdmplex.h>
> > #include <petscdmadaptor.h>
> > #include <petscds.h>
> > #include <petscviewerhdf5.h>
> >
> > class DMManage{
> >   PetscSF distributionSF;
> > public:
> >   DM dm;
> >   DMManage();
> >   ~DMManage();
> > };
> >
> > DMManage::DMManage(){
> >   const char filename[] = "ParallelWaveguide.msh";
> >   DM dmDist;
> >   PetscViewer viewer;
> >   PetscViewerCreate(PETSC_COMM_WORLD, &viewer);
> >   PetscViewerSetType(viewer, PETSCVIEWERASCII);
> >   PetscViewerFileSetMode(viewer, FILE_MODE_READ);
> >   PetscViewerFileSetName(viewer, filename);
> >   DMPlexCreateGmsh(PETSC_COMM_WORLD, viewer, PETSC_TRUE, &dm);
> >   PetscViewerDestroy(&viewer);
> >   PetscInt overlap = 0;
> >   DMPlexDistribute(dm, overlap, &distributionSF, &dmDist);
> >   std::cout<<&dm<<std::endl;
> >   if (dmDist) {
> >     DMDestroy(&dm);
> >     dm = dmDist;
> >   }
> >   DMDestroy(&dmDist);
> > }
> >
> > DMManage::~DMManage(){
> >   DMDestroy(&dm);
> > }
> >
> > int main(int argc, char** argv) {
> >   PetscFunctionBeginUser;
> >   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
> >
> >   DMManage objDMManage;
> >
> >   PetscFinalize();
> >   return 0;
> > }
>
> --
> Constantine
>
>
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