#include <petscmat.h>

int main(int argc,char **argv)
{
   Mat            A, B;
   const char     *pfx;

   PetscCall(PetscInitialize(&argc, &argv, NULL, NULL));
   PetscCall(MatCreate(PETSC_COMM_WORLD, &A));
   PetscCall(MatSetSizes(A, 1, 1, PETSC_DECIDE, PETSC_DECIDE));
   PetscCall(MatSetUp(A));
   PetscCall(MatSetOptionsPrefix(A, "foo_"));
   PetscCall(MatGetDiagonalBlock(A, &B));
   /* Test set options prefix with the string obtained from get options prefix */
   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)A,&pfx));
   PetscCall(MatSetOptionsPrefix(B, pfx));
   PetscCall(MatDestroy(&A));

  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

   test:

TEST*/