# UNDOMARKS System Variable [GstarCAD 2021](Help%20System/GSTARCAD/2021/Index.md) → [System Variables](Help%20System/GSTARCAD/2021/System%20Variables/(System%20Variables).md) → [U](Help%20System/GSTARCAD/2021/System%20Variables/U/(U).md) **Function Description:** The UNDOMARKS system variable is used to display the mark number placed in UNDO control stream. (Read-Only) | | | | --- | --- | | Type | Integer | | Saved in | Not saved | | Initial value | 0 | If one group is currently active, the Mark and Back options are disabled. --- ## Other versions with matching text [GstarCAD 2016](../../../2016/System%20Variables/U/UNDOMARKS%20System%20Variable--bcb45ad4385f.md) · [GstarCAD 2017](Help%20System/GSTARCAD/2017/System%20Variables/U/UNDOMARKS%20System%20Variable--bcb45ad4385f.md) · [GstarCAD 2018](../../../2018/System%20Variables/U/UNDOMARKS%20System%20Variable--bcb45ad4385f.md) · [GstarCAD 2019](../../../2019/System%20Variables/U/UNDOMARKS%20System%20Variable--bcb45ad4385f.md) · [GstarCAD 2020](../../../2020/System%20Variables/U/UNDOMARKS%20System%20Variable--bcb45ad4385f.md) · [GstarCAD 2022](Help%20System/GSTARCAD/2022/System%20Variables/U/UNDOMARKS%20System%20Variable--bcb45ad4385f.md)