:orphan: # PetscDrawIsNull Returns `PETSC_TRUE` if draw is a null draw object. ## Synopsis ``` #include "petscdraw.h" PetscErrorCode PetscDrawIsNull(PetscDraw draw, PetscBool *yes) ``` Not Collective ## Input Parameter - ***draw -*** the draw context ## Output Parameter - ***yes -*** `PETSC_TRUE` if it is a null draw object; otherwise `PETSC_FALSE` ## See Also `PetscDraw`, `PETSC_DRAW_NULL`, `PetscDrawOpenX()`, `PetscDrawIsNull()` ## Level advanced ## Location src/sys/classes/draw/impls/null/drawnull.c --- [Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/sys/classes/draw/impls/null/drawnull.c) [Index of all Draw routines](index.md) [Table of Contents for all manual pages](/manualpages/index.md) [Index of all manual pages](/manualpages/singleindex.md)