void/notes/multi-language-library.md

tags
dev

Multi Language Library

To create a library that can be used in multiple languages, the language that is going to implement the library needs to support notes/ffi with the language that the library is written in.

With this in, we can use the following in our favor:

• It's impossible that every language support every other language.
• For compatibility reasons, Almost every language supports C's notes/abi for their notes/ffi.
• Some compiled language has the avility to compile a C's "dynamic library" (.so file in unix and .dll in windows).
• The notes/ffi use a "dynamic library" to work.

So, in conclusion: we can use whatever language that supports compiling to C's ABI to build multi language libraries

List of language that compiles to C's ABI

Go

To produce a shared library, you need to compile it with compile with: go build -buildmode=c-shared.

Note that the documentation says you need to specify with functions needs to be exported:

Build the listed main package, plus all packages it imports, into a C shared library. The only callable symbols will be those functions exported using a cgo //export comment. Requires exactly one main package to be listed.

Example:

src/go/main.go:

package main

import "C"
import "fmt"

//export helloLib
func helloLib(x C.int) {
    fmt.Printf("Hello from Go! x=%d\n", x)
}

func main() {}

src/c/main.c:

void helloLib(int);

int main() {
    helloLib(12345);
}

Building and running:

go build -buildmode=c-shared -o libmy.so ./src/go/
gcc -o test src/c/main.c libmy.so
./test
Hello from Go! x=12345

Sources:

• https://stackoverflow.com/questions/75035609/can-go-executable-be-used-as-a-dynamic-library
• https://pkg.go.dev/cmd/go#hdr-Build_modes

List of languages that has support for FFI with C