go-ffi-demo

Examples for building a shared library with the Go 1.5 c-shared buildmode, and then interfacing with this library in C, Python, and Node.

There is a proof-of-concept in each language for:

• Passing native string arguments to Go functions
• Calling Go functions which return strings
• Passing native array/list arguments to Go functions
• Calling Go functions which return a Go slice
• Passing native function pointers and having them called by Go
• Receiving and calling Go function pointers

Instructions

1. Build the Go 'hello' package

   go-ffi-demo$ GOPATH=$GOPATH:$(pwd)/go go install hello
   

2. Build the Go 'libhello' shared library

   go-ffi-demo$ GOPATH=$GOPATH:$(pwd)/go go build -buildmode=c-shared -o libhello.so libhello
   

3. Build and run the C demo program:

   go-ffi-demo$ gcc -Wall -o c/demo c/demo.c ./libhello.so
   go-ffi-demo$ c/demo
   StringFromGo(): Hello from Go!
   StringToGo(): Calling from C
   ArrayFromGo(): 1 2 3
   ArrayToGo(): 4 5 6
   CallbackInC(): Calling from Go
   CallbackInGo(): Calling from C
   

4. Run the python demo program:

   go-ffi-demo$ python python/demo.py
   StringFromGo(): Hello from Go!
   StringToGo(): Calling from Python
   ArrayFromGo(): 1 2 3
   ArrayToGo(): 4 5 6
   CallbackInPython(): Calling from Go
   CallbackInGo(): Calling from Python
   

5. Install and run the Node demo program:

   go-ffi-demo$ ( cd node && npm install )
   go-ffi-demo$ node node/demo.js
   StringFromGo(): Hello from Go!
   StringToGo(): Calling from Node
   ArrayFromGo(): 1 2 3
   ArrayToGo(): 4 5 6
   CallbackInNode(): Calling from Go
   CallbackInGo(): Calling from Node