Call C++ Library from Go using shared library with SWIG

go_cpp_swig_linkage.md

Introduction

SWIG can generate interface for other languages to call C++ functions. If C++ codes are separeted to mutiple directories, we may have some trouble.

Build Flow

1. Prepare directories like this.

- invoke
  - invoke.cpp
  - invoke.hpp
- lib.cpp
- lib.hpp
- lib.i

%module lib
%{
#include "lib.hpp"
%}

%include "lib.hpp"

Other files are described in go_cpp_linkage.md.

2. Create shared library

clang++ invoke.cpp -shared -fPIC -o libinvoke.so

3. Genarate glue codes

swig -go -c++ -cgo -intgosize 64 lib.i

4. Add to enable dynamic linking to lib.go

  ・
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  ・
// source: lib/lib.i

package lib

/*
#cgo LDFLAGS: -L ./ -linvoke -ldl
  ・
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5. Check your LD_LIBRARY_PATH. If it is not included the location of libinvoke.so, you must add them to it.

export LD_LIBRARY_PATH=~/go/src/github.com/Shikugawa/go-cpp-ffi/lib:$LD_LIBRARY_PATH

6. Build