:orphan:
# PETSC_COMM_SELF
This is always `MPI_COMM_SELF`
## Notes
Do not USE/access or set this variable before `PetscInitialize()` has been called.
## See Also
`PETSC_COMM_WORLD`
## Level
beginner
## Location
include/petscsys.h
## Examples
src/dm/dt/dualspace/impls/lagrange/tutorials/ex2.c
src/dm/field/tutorials/ex1.c
src/dm/impls/plex/tutorials/ex10.c
src/dm/impls/plex/tutorials/ex11.c
src/dm/impls/plex/tutorials/ex1f90.F90
src/dm/impls/plex/tutorials/ex6.c
src/dm/impls/plex/tutorials/ex8.c
src/dm/impls/swarm/tutorials/ex1.c
src/dm/impls/swarm/tutorials/ex1f90.F90
src/dm/label/tutorials/ex1.c
src/dm/tutorials/ex14.c
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/include/petscsys.h)
[Index of all Sys routines](index.md)
[Table of Contents for all manual pages](/manualpages/index.md)
[Index of all manual pages](/manualpages/singleindex.md)