# Extensions build error (e.g. SlicerJupyter)

**URL:** <https://discourse.slicer.org/t/extensions-build-error-e-g-slicerjupyter/10346>\
**Category:** Support\
**Created:** [February 19, 2020, 12:14am UTC](https://discourse.slicer.org/t/extensions-build-error-e-g-slicerjupyter/10346 "2020-02-19T00:14:41Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ungi](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ungi/32/78573_2.png) [@ungi](https://discourse.slicer.org/u/ungi)\
**Post date:** [February 19, 2020, 12:14am UTC](https://discourse.slicer.org/t/extensions-build-error-e-g-slicerjupyter/10346/1 "2020-02-19T00:14:41Z")

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Hi,

I wanted to update my Slicer Preview version. I need the SlicerJupyter extension, but I noticed that it has build errors for a couple of weeks now. I went back in the CDash calendar to a date when it was built, but the yellow box icon was missing that I usually use to download the Slicer installer for Windows (it was there for the other platforms, just not Windows). I had to go back to early January to find a date when both the Windows installer and SlicerJupyter was available.  
Is anybody working on fixing these build errors?

Thanks,  
Tamas

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**Author:** ![jamesobutler](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jamesobutler/32/7511_2.png) [@jamesobutler](https://discourse.slicer.org/u/jamesobutler)\
**Post date:** [February 19, 2020, 12:30am UTC](https://discourse.slicer.org/t/extensions-build-error-e-g-slicerjupyter/10346/2 "2020-02-19T00:30:45Z")

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I haven’t been working on fixing SlicerJupyter, but did just take a look. The main build error for the extension started for the Slicer build started February 8th 2020.

SlicerJupyter has an external project for cppzmq which uses the master branch for that project. That project issued [https://github.com/zeromq/cppzmq/commit/324b11f23951127423f66839bdc8cad53ff76c8f](https://github.com/zeromq/cppzmq/commit/324b11f23951127423f66839bdc8cad53ff76c8f) on the 7th which is also still the latest commit on the master branch.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [February 19, 2020, 12:38am UTC](https://discourse.slicer.org/t/extensions-build-error-e-g-slicerjupyter/10346/3 "2020-02-19T00:38:41Z")

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Thanks for checking this. I’ll try if using a specific hash on cppzmq master fixes the build error.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [February 19, 2020, 1:14am UTC](https://discourse.slicer.org/t/extensions-build-error-e-g-slicerjupyter/10346/4 "2020-02-19T01:14:39Z")

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Confirmed that the change @jamesobutler found caused the build error. I’ve [reported the error to cppzmq](https://github.com/zeromq/cppzmq/issues/385). In the meantime, to fix the build error, I have [locked SlicerJupyter to use the previous commit](https://github.com/Slicer/SlicerJupyter/commit/2d867440bf98f2bff483a7df7a73a92a022b2cc7).