Error: undefined symbol: omp_init_lock only when compiling with node-gyp

Question

I am trying to compile a c++ addon that uses an external library. My bindings.gyp file looks like this:

{
  "targets": [
    {
      "target_name": "addon",
      "sources": [ "addon.cc" ],
      "include_dirs": [
        "<!(node -e \"require('nan')\")"
      ],
      "libraries":[
        "/home/ubuntu/workspace/libdds.a" 
      ],         
    }
  ]
}

When I try to compile it with node-gyp, it compiles fine but on runtime I get the following error:

Error: /home/ubuntu/workspace/build/Release/addon.node: undefined symbol: omp_init_lock
    at Error (native)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Module.require (module.js:365:17)
    at require (module.js:384:17)
    at Object.<anonymous> (/home/ubuntu/workspace/addon.js:1:75)
    at Module._compile (module.js:460:26)
    at Object.Module._extensions..js (module.js:478:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)

omp_int_lock isn't in addon.cc code but instead in the libdds.a library I am trying to use. I tried taking my code and just converting it to a command line program. Compiling it like so:

g++ -o ddsolver -O2 -Wall leadsolver.cpp libdds.a -lgomp

It compiles and runs fine. Has anyone seen this problem before?

Answer 1

Seems like your external library libdds.a uses OpenMP for parallel execution and since it is statically linked you need to provide -lgomp to resolve all the dependencies.

I think you can also compile it with -fopenmp instead of -lgomp