static char help[] = "Tests retrieving unused PETSc options.\n\n";

#include <petscsys.h>

int main(int argc, char **argv)
{
  PetscInt  i, N, M;
  char    **names, **values;
  PetscBool set;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));

  PetscCall(PetscOptionsGetInt(NULL, NULL, "-get_an_integer", &M, &set));
  if (set) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Option used: name:-get_an_integer value: %" PetscInt_FMT "\n", M));
  PetscCall(PetscOptionsLeftGet(NULL, &N, &names, &values));
  for (i = 0; i < N; i++) {
    if (values[i]) {
      PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Option left: name:-%s value: %s\n", names[i], values[i]));
    } else {
      PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Option left: name:-%s (no value)\n", names[i]));
    }
  }
  PetscCall(PetscOptionsLeftRestore(NULL, &N, &names, &values));

  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

   test:
      suffix: debug
      requires: defined(PETSC_USE_DEBUG)
      args: -unused_petsc_option_1 -unused_petsc_option_2 -get_an_integer 10 -options_left no

   test:
      suffix: opt
      requires: !defined(PETSC_USE_DEBUG)
      args: -unused_petsc_option_1 -unused_petsc_option_2 -get_an_integer 10 -options_left no

 TEST*/