179     DMLabel  label0, label1, label2, label3;  in main()  local
195     PetscCall(DMLabelDuplicate(label0, &label2));  in main()
197     PetscCall(PetscObjectSetName((PetscObject)label2, "label2"));  in main()
199     PetscCall(DMAddLabel(dm, label2));  in main()
203     PetscCall(DMLabelDestroy(&label2));  in main()
211     DMLabel  label0, label1, label2, label3;  in main()  local
217     PetscCall(DMGetLabel(dm, "label2", &label2));  in main()
221     PetscCall(CheckLabelsSame(label0, label2));  in main()
324     DMLabel label0, label1, label2;  in main()  local
330     PetscCall(DMRemoveLabel(dm, "label2", &label2));  in main()
336     PetscCheck(label2, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "label2 must not be NULL now");  in main()
337     PetscCall(DMRemoveLabelBySelf(dm, &label2, PETSC_FALSE)); /* this should do nothing */  in main()
338     PetscCheck(label2, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "label2 must not be NULL now");  in main()
339     PetscCall(DMLabelDestroy(&label2));  in main()
340     PetscCall(DMGetLabel(dm, "label2", &label2));  in main()
341     PetscCheck(!label2, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "label2 must be NULL now");  in main()