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# PetscCopyMode

Determines how an array or `PetscObject` passed to certain functions is copied or retained by the aggregate `PetscObject`

## Synopsis

    typedef enum {
      PETSC_COPY_VALUES,
      PETSC_OWN_POINTER,
      PETSC_USE_POINTER
    } PetscCopyMode;

## Values for array input

- `PETSC_COPY_VALUES` - the array values are copied into new space, the user is free to reuse or delete the passed in array

- `PETSC_OWN_POINTER` - the array values are NOT copied, the object takes ownership of the array and will free it later, the user cannot change or delete the array. The array MUST have been obtained with `PetscMalloc()`. Hence this mode cannot be used in Fortran.

- `PETSC_USE_POINTER` - the array values are NOT copied, the object uses the array but does NOT take ownership of the array. The user cannot use the array but the user must delete the array after the object is destroyed.

## Values for PetscObject

- `PETSC_COPY_VALUES` - the input `PetscObject` is cloned into the aggregate `PetscObject`; the user is free to reuse/modify the input `PetscObject` without side effects.

- `PETSC_OWN_POINTER` - the input `PetscObject` is referenced by pointer (with reference count), thus should not be modified by the user. increases its reference count).

- `PETSC_USE_POINTER` - invalid for `PetscObject` inputs.

## See Also

`InsertMode`

## Level

beginner

## Location

include/petscsystypes.h

## Examples

src/ksp/ksp/tutorials/ex85.c
src/ksp/ksp/tutorials/ex59.c
src/ksp/ksp/tutorials/ex71.c
src/ksp/ksp/tutorials/ex49.c
src/dm/tutorials/ex6.c
src/ksp/ksp/tutorials/ex84.c
src/ksp/ksp/tutorials/ex76.c
src/mat/tutorials/ex3.c
src/dm/label/tutorials/ex1.c
src/ksp/ksp/tutorials/ex87.c

## Examples

src/ksp/ksp/tutorials/ex85.c
src/dm/tutorials/swarm_ex3.c
src/ksp/ksp/tutorials/ex59.c
src/ksp/ksp/tutorials/ex71.c
src/dm/tutorials/ex6.c
src/dm/label/tutorials/ex1.c
src/dm/impls/plex/tutorials/ex6.c
src/dm/field/tutorials/ex1.c

## Examples

src/dm/label/tutorials/ex1.c
src/dm/tutorials/ex22.c
src/ksp/pc/tutorials/ex4.c

Index of all Sys routines
Table of Contents for all manual pages
Index of all manual pages