# Building an existing extension

**URL:** <https://discourse.slicer.org/t/building-an-existing-extension/815>\
**Category:** Support\
**Created:** [August 3, 2017, 3:34pm UTC](https://discourse.slicer.org/t/building-an-existing-extension/815 "2017-08-03T15:34:13Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![crossmanith](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/crossmanith/32/1095_2.png) [@crossmanith](https://discourse.slicer.org/u/crossmanith)\
**Post date:** [August 3, 2017, 3:34pm UTC](https://discourse.slicer.org/t/building-an-existing-extension/815/1 "2017-08-03T15:34:13Z")

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```auto
Operating system : Linux 4.4.25-040425-generic (Ubuntu 16.04.2 LTS)
Slicer version : Slicer-4.7.0-2017-07-10-linux-amd64
Expected behavior : -
Actual behavior : -

```

`DTIProcess` is available as extension for Slicer but the Extension Manager can’t find it.

Probably because it is a very recent version of Slicer.

I’ve cloned `DTIProcess` from github but don’t have an idea how to build it as an extension. Any hints how to proceed?

Regards,  
Christina Roßmanith

Dept. of Neurology  
University Medicine Mannheim  
University of Heidelberg

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [August 3, 2017, 6:33pm UTC](https://discourse.slicer.org/t/building-an-existing-extension/815/2 "2017-08-03T18:33:21Z")

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Hi -

It looks like there’s a build error on the linux version of DTIProcess at the moment:

[http://slicer.cdash.org/viewBuildError.php?buildid=1074584](http://slicer.cdash.org/viewBuildError.php?buildid=1074584)

but windows and mac appear to be working.

If you don’t hear more on this forum you could contact the authors listed here:

[https://www.slicer.org/wiki/Documentation/Nightly/Extensions/DTIProcess](https://www.slicer.org/wiki/Documentation/Nightly/Extensions/DTIProcess)

To answer your original question, you can do what is described here:

[https://www.slicer.org/wiki/Documentation/Nightly/Developers/Build\_Module](https://www.slicer.org/wiki/Documentation/Nightly/Developers/Build_Module)

It requires also building Slicer on your machine (and the build error from the extension factory will need to be fixed)

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<div class="post-metadata">

**Author:** ![crossmanith](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/crossmanith/32/1095_2.png) [@crossmanith](https://discourse.slicer.org/u/crossmanith)\
**Post date:** [August 4, 2017, 9:40am UTC](https://discourse.slicer.org/t/building-an-existing-extension/815/3 "2017-08-04T09:40:20Z")

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I’ve built DTIProcess locally but had to add the line “set( CMAKE\_CXX\_STANDARD\_REQUIRED ON )” to SuperBuild.cmake of DTIProcess to make the " CXX\_STANDARD is set to invalid value ‘’ errors disappear. I’ve emailed Francois already. Maybe they modify the DTIProcess SuperBuild.cmake - if the fix is feasible. Is there a way to influence building DTIProcess from the Slicer build process and to add this option there, too?

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<div class="post-metadata">

**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [August 4, 2017, 1:02pm UTC](https://discourse.slicer.org/t/building-an-existing-extension/815/4 "2017-08-04T13:02:08Z")

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Glad you got it working - I’m not sure if this is something specific to DTIProcess or something that might apply to all extensions. My guess is that your change should be applied in the DTIProcess code.