# PETSC_IGNORE
same as NULL, means PETSc will ignore this argument 


## Note
Accepted by many PETSc functions to not set a parameter and instead use some default


## Fortran Note
This macro does not exist in Fortran; you must use `PETSC_NULL_INTEGER`, `PETSC_NULL_DOUBLE_PRECISION` etc


## See Also
 `PETSC_DECIDE`, `PETSC_DEFAULT`, `PETSC_DETERMINE`


## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/include/petscsys.h.html#PETSC_IGNORE">include/petscsys.h</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex14.c.html">src/snes/tutorials/ex14.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex15.c.html">src/snes/tutorials/ex15.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex16.c.html">src/snes/tutorials/ex16.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex19.c.html">src/snes/tutorials/ex19.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex22.c.html">src/snes/tutorials/ex22.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex35.c.html">src/snes/tutorials/ex35.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex47cu.cu.html">src/snes/tutorials/ex47cu.cu.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex5.c.html">src/snes/tutorials/ex5.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex55.c.html">src/snes/tutorials/ex55.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex58.c.html">src/snes/tutorials/ex58.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex12.c.html">src/ts/tutorials/ex12.c.html</A><BR>


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[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](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
