# Building VTK with CMake 3.15

**URL:** <https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370>\
**Category:** Development\
**Created:** [July 17, 2019, 11:08pm UTC](https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370 "2019-07-17T23:08:04Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![amaclean](https://discourse.vtk.org/user_avatar/discourse.vtk.org/amaclean/32/224_2.png) [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Post date:** [July 17, 2019, 11:08pm UTC](https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370/1 "2019-07-17T23:08:04Z")

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The build fails with:

```auto
CMake Error at Common/Core/CMakeLists.txt:442 (check_symbol_exists):
  Unknown CMake command "check_symbol_exists".

```

The fix is to add:

```auto
include(CheckSymbolExists)

```

However should this be added to the top level CmakeLists.txt?

@ben.boeckel I’ll let you make the decision since you are really familiar with the CMake files in VTK! Not sure why this issue pops up in CMake 3.15 but not earlier versions of CMake.

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**Author:** ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Post date:** [July 18, 2019, 7:40am UTC](https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370/2 "2019-07-18T07:40:46Z")

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Maybe some module that used to include it stopped including it. The inclusion should be added near to where `check_symbol_exists` is used (i.e., in `Common/Core/CMakeList.txt` itself).

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<div class="post-metadata">

**Author:** ![amaclean](https://discourse.vtk.org/user_avatar/discourse.vtk.org/amaclean/32/224_2.png) [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Post date:** [July 18, 2019, 7:50am UTC](https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370/3 "2019-07-18T07:50:15Z")

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Ok if you don’t get around to doing it, I’ll do a MR tomorrow, around 22:00 UTC, 19 Jul

Andrew Maclean

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<div class="post-metadata">

**Author:** ![amaclean](https://discourse.vtk.org/user_avatar/discourse.vtk.org/amaclean/32/224_2.png) [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Post date:** [July 18, 2019, 10:57pm UTC](https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370/4 "2019-07-18T22:57:23Z")

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MR: [update-for-CMake-v3.15](https://gitlab.kitware.com/vtk/vtk/merge_requests/5767) has been submitted.