# Undefined symbol with libcxxwrap-julia

**URL:** <https://discourse.julialang.org/t/undefined-symbol-with-libcxxwrap-julia/23743>\
**Category:** New to Julia\
**Created:** [May 1, 2019, 6:23pm UTC](https://discourse.julialang.org/t/undefined-symbol-with-libcxxwrap-julia/23743 "2019-05-01T18:23:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Josiah\_Slack](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/josiah_slack/32/8319_2.png) [@Josiah\_Slack](https://discourse.julialang.org/u/Josiah_Slack)\
**Post date:** [May 1, 2019, 6:23pm UTC](https://discourse.julialang.org/t/undefined-symbol-with-libcxxwrap-julia/23743/1 "2019-05-01T18:23:12Z")

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Some time ago I built a C++ shared library that depends on `libcxxwrap-julia`. I’ve been loading it into Julia with no problems until this morning. I updated a package dependency that has absolutely nothing to do with the shared library, and when I tried to run my unit tests I got this:  
`.../julia-1.1.0/bin/julia: symbol lookup error: /usr/local/lib/libgeometry_wrap.so: undefined symbol: _ZN5jlcxx12gc_index_mapEv`

Demangling the name gives: `jlcxx::gc_index_map()`  
I’ve rebuilt and reinstalled my library, and libcxxwrap-julia to no avail.

Any suggestions of what to try next would be welcome.

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<div class="post-metadata">

**Author:** ![Josiah\_Slack](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/josiah_slack/32/8319_2.png) [@Josiah\_Slack](https://discourse.julialang.org/u/Josiah_Slack)\
**Post date:** [May 2, 2019, 1:43pm UTC](https://discourse.julialang.org/t/undefined-symbol-with-libcxxwrap-julia/23743/2 "2019-05-02T13:43:21Z")

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Answering my own question here. Apparently CxxWrap went from version 0.8.1 to 0.8.2 recently. I pinned the version to 0.8.1, and the linker problem vanished. This led me to update my libcxxwrap-julia source, rebuild and reinstall it. I then rebuild and reinstall my own wrapper library. I then unpinned and updated CxxWrap, and my tests loaded and ran without any problems.