# Point Julia to Cbc built from source

**URL:** <https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516>\
**Category:** Optimization (Mathematical)\
**Tags:** question, jump\
**Created:** [March 25, 2020, 7:56pm UTC](https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516 "2020-03-25T19:56:12Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![joshuastowell25](https://avatars.discourse-cdn.com/v4/letter/j/e5b9ba/32.png) [@joshuastowell25](https://discourse.julialang.org/u/joshuastowell25)\
**Post date:** [March 25, 2020, 7:56pm UTC](https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516/1 "2020-03-25T19:56:12Z")

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Hello All,

I am trying to get JuMP and Cbc to use multithreading. Turns out that in order to do this you have to build Cbc from source with the --enable-cbc-parallel option.

I have followed the cbc build instructions instructions here: [GitHub - coin-or/Cbc: COIN-OR Branch-and-Cut solver](https://github.com/coin-or/Cbc) to build Cbc using coinbrew.

Now I need to point Julia to my newly built version of Cbc. This is the part I am having trouble with.

According to [GitHub - jump-dev/Cbc.jl: Julia wrapper for the Cbc solver](https://github.com/JuliaOpt/Cbc.jl) all that is needed is:  
ENV[“JULIA\_CBC\_LIBRARY\_PATH”]=“path/to/custom/built/binaries”  
then  
import Pkg; Pkg.build(“Cbc”)

I point my julia cbc library path to the dist/lib folder containing the libCbc.la and libCbcSolver.la files, but keep getting the following error:  
┌ Error: Error building `Cbc`:  
│ ERROR: LoadError: Could not install custom libraries from C:/Users/me/path/to/dist/lib.  
│ To fall back to BinaryProvider call delete!(ENV,“JULIA\_CBC\_LIBRARY\_PATH”) and run build again.  
│ Stacktrace:  
│ [1] error(::String) at .\error.jl:33  
│ [2] top-level scope at C:\Users\me.julia\packages\Cbc\zMLXd\deps\build.jl:66  
│ [3] include at .\boot.jl:328 [inlined]  
│ [4] include\_relative(::Module, ::String) at .\loading.jl:1105  
│ [5] include(::Module, ::String) at .\Base.jl:31  
│ [6] include(::String) at .\client.jl:424  
│ [7] top-level scope at none:5  
│ in expression starting at C:\Users\me.julia\packages\Cbc\zMLXd\deps\build.jl:60

Any help would be very much appreciated. Thanks

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**Author:** ![ericphanson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ericphanson/32/215186_2.png) [@ericphanson](https://discourse.julialang.org/u/ericphanson)\
**Post date:** [March 25, 2020, 8:47pm UTC](https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516/2 "2020-03-25T20:47:22Z")

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Just for your information, I moved your question to the Domains/Optimization section, so it’s more likely to be seen by JuMP users and developers.

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**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [March 25, 2020, 8:57pm UTC](https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516/3 "2020-03-25T20:57:41Z")

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You may need to point it at the actual DLLs in `/bin`. (Or perhaps even the parent of `/lib` and `/bin`.) I’m not sure what’s needed on Windows.

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**Author:** ![joshuastowell25](https://avatars.discourse-cdn.com/v4/letter/j/e5b9ba/32.png) [@joshuastowell25](https://discourse.julialang.org/u/joshuastowell25)\
**Post date:** [March 25, 2020, 9:59pm UTC](https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516/4 "2020-03-25T21:59:13Z")

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Thanks for the reply odow! I have tried pointing it to /lib, /bin, and even their parent; /dist.  
But I get the same error every time.

Is there any chance you know what file types the package manager is looking for?

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**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [March 25, 2020, 11:11pm UTC](https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516/5 "2020-03-25T23:11:29Z")

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Install `Cbc.jl` using the provided binaries, then look at the `deps` folder to see what was installed.

I haven’t used custom binaries with binary builder on Windows, so I’m not sure.

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**Author:** ![joshuastowell25](https://avatars.discourse-cdn.com/v4/letter/j/e5b9ba/32.png) [@joshuastowell25](https://discourse.julialang.org/u/joshuastowell25)\
**Post date:** [March 27, 2020, 3:30pm UTC](https://discourse.julialang.org/t/point-julia-to-cbc-built-from-source/36516/6 "2020-03-27T15:30:57Z")

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Hi Odow,

Do you have any experience doing so in a unix environment? I have access to an ubuntu machine.