# CMake unknown argument : Support for 64 bit file systems on Ubuntu 18.04
**URL:** https://discourse.paraview.org/t/cmake-unknown-argument-support-for-64-bit-file-systems-on-ubuntu-18-04/5646
**Category:** ParaView Support
**Created:** [October 24, 2020, 3:41pm UTC](https://discourse.paraview.org/t/cmake-unknown-argument-support-for-64-bit-file-systems-on-ubuntu-18-04/5646 "2020-10-24T15:41:55Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@williamfgc](https://discourse.paraview.org/u/williamfgc)
#### Post date: [October 24, 2020, 3:41pm UTC](https://discourse.paraview.org/t/cmake-unknown-argument-support-for-64-bit-file-systems-on-ubuntu-18-04/5646/1 "2020-10-24T15:41:56Z")
I’m running into this issue when configuring ParaView master on Ubuntu 18.04 using gcc 8 from synaptic and CMake 3.19.0-rc1. This is a 64-bit system (AMD Ryzen 7 3700X) and I haven’t seen this error in the past with CMake projects. VTK compiles and runs fine BTW. Any help would be appreciated.
Thanks!
```auto
The C compiler identification is GNU 8.4.0
The CXX compiler identification is GNU 8.4.0
Detecting C compiler ABI info
Detecting C compiler ABI info - done
Check for working C compiler: /usr/bin/cc - skipped
Detecting C compile features
Detecting C compile features - done
Detecting CXX compiler ABI info
Detecting CXX compiler ABI info - done
Check for working CXX compiler: /usr/bin/c++ - skipped
Detecting CXX compile features
Detecting CXX compile features - done
Setting build type to 'Debug' as none was specified.
Performing Test HAVE_GCC_ERROR_RETURN_TYPE
Performing Test HAVE_GCC_ERROR_RETURN_TYPE - Success
Looking for a Fortran compiler
Looking for a Fortran compiler - /usr/bin/gfortran
CMake Error at /usr/share/cmake-3.19/Modules/CheckSourceRuns.cmake:122 (message):
Unknown argument:
Support for 64 bit file systems
Call Stack (most recent call first):
/usr/share/cmake-3.19/Modules/CheckCXXSourceRuns.cmake:71 (check_source_runs)
CMakeLists.txt:123 (check_cxx_source_runs)
Configuring incomplete, errors occurred!
See also "/home/wgodoy/workspace/paraview-build/CMakeFiles/CMakeOutput.log".
```
---
### Author:  [@ben.boeckel](https://discourse.paraview.org/u/ben.boeckel)
#### Post date: [October 26, 2020, 12:04pm UTC](https://discourse.paraview.org/t/cmake-unknown-argument-support-for-64-bit-file-systems-on-ubuntu-18-04/5646/2 "2020-10-26T12:04:29Z")
This looks like a regression in 3.19. Thanks for the report.
Cc: @brad.king @robert.maynard
---
### Author:  [@ben.boeckel](https://discourse.paraview.org/u/ben.boeckel)
#### Post date: [October 26, 2020, 12:29pm UTC](https://discourse.paraview.org/t/cmake-unknown-argument-support-for-64-bit-file-systems-on-ubuntu-18-04/5646/3 "2020-10-26T12:29:50Z")
I’ve submitted a fix for the regression here: [https://gitlab.kitware.com/cmake/cmake/-/merge\_requests/5426](https://gitlab.kitware.com/cmake/cmake/-/merge_requests/5426)
---
### Author:  [@ben.boeckel](https://discourse.paraview.org/u/ben.boeckel)
#### Post date: [October 26, 2020, 12:32pm UTC](https://discourse.paraview.org/t/cmake-unknown-argument-support-for-64-bit-file-systems-on-ubuntu-18-04/5646/4 "2020-10-26T12:32:00Z")
And a fix to make ParaView not care about the new behavior anyways: [https://gitlab.kitware.com/paraview/paraview/-/merge\_requests/4481](https://gitlab.kitware.com/paraview/paraview/-/merge_requests/4481)
---
### Author:  [@williamfgc](https://discourse.paraview.org/u/williamfgc)
#### Post date: [October 26, 2020, 12:41pm UTC](https://discourse.paraview.org/t/cmake-unknown-argument-support-for-64-bit-file-systems-on-ubuntu-18-04/5646/5 "2020-10-26T12:41:41Z")
@ben.boeckel thanks for the quick response, those are fast fixes. Happy to help from my side. Looking forward to the fixes.