# CMAKE Generation issue in Ubuntu
**URL:** https://discourse.vtk.org/t/cmake-generation-issue-in-ubuntu/5687
**Category:** Development
**Created:** [May 3, 2021, 9:08am UTC](https://discourse.vtk.org/t/cmake-generation-issue-in-ubuntu/5687 "2021-05-03T09:08:32Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Homersbm](https://discourse.vtk.org/u/Homersbm)
#### Post date: [May 3, 2021, 9:08am UTC](https://discourse.vtk.org/t/cmake-generation-issue-in-ubuntu/5687/1 "2021-05-03T09:08:32Z")
I am having trouble generating cmake files in ubuntu.
Can someone help with the **Compatibility** metrics of the various vtx versions
VTK Version G++ version Cmake Version
- 9 -----------?-----------------------?
- 8 -----------?-----------------------?
- 6.3 -----------?-----------------------?
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [May 3, 2021, 10:57am UTC](https://discourse.vtk.org/t/cmake-generation-issue-in-ubuntu/5687/2 "2021-05-03T10:57:04Z")
What are you trying to generate? I know that VTK 6.3 doesn’t support GCC 9+ due to some silly compiler detection routines, I forget about VTK 8, and 9 supports whatever CMake ends up detecting.
---
### Author:  [@Homersbm](https://discourse.vtk.org/u/Homersbm)
#### Post date: [May 3, 2021, 12:20pm UTC](https://discourse.vtk.org/t/cmake-generation-issue-in-ubuntu/5687/3 "2021-05-03T12:20:49Z")
I just wanted to run CMAKE so that i can build a C++ project to generate the .so files of VTK . I am using
CMAKE 3.20.2 with Unix MakeFiles
G++ 9.3
and I have tried vtx 9.0 and 8.2
for 9.0 i have the following error:
Could NOT find X11 (missing: Xt)
CMake Error at CMake/vtkModule.cmake:4140 (message):
Could not find the X11 external dependency.
Call Stack (most recent call first):
Rendering/OpenGL2/CMakeLists.txt:334 (vtk\_module\_find\_package)
and i have tried ```
sudo apt-get install libx11-dev
```auto
to resolve but without any success
```
---
### Author:  [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [May 3, 2021, 12:54pm UTC](https://discourse.vtk.org/t/cmake-generation-issue-in-ubuntu/5687/4 "2021-05-03T12:54:16Z")
sudo apt-get install libxt-dev
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [May 3, 2021, 12:59pm UTC](https://discourse.vtk.org/t/cmake-generation-issue-in-ubuntu/5687/5 "2021-05-03T12:59:49Z")
I also see [this posting](https://discourse.vtk.org/t/error-while-running-cmake-configure-on-vtk9-0-in-ubuntu/5688) with the same question. And yes, `libx11-dev` would not contain libXt; that would be `libxt-dev` as said above.