DynamicLibrary in Rust to Others Languages - FFI

cargo.toml

[package]
name = "cs_call_rst"
version = "0.1.0"

[lib]
name="fib_rust"
crate-type = ["cdylib"]

[dependencies]

fib_dll.cpp

#include <cstdint>

template<typename T> T fib(T n)
{
  return n > 1 ? fib(n - 1) + fib(n - 2) : 1;
}

template uint64_t fib<uint64_t>(uint64_t);
//GCC command: g++ -Wall -O3 -c -fPIC fib_dll.cpp && g++ -shared -o fib_cpp.dll fib_cpp.o

lib.rs

#[no_mangle] //mantém o nome da função de forma externa
pub extern fn fib2(n: u64) -> u64 {
    if n > 1
  {
    return fib(n - 1) + fib(n - 2);
  }
  1
}

Program.cpp

#include <iostream>
#include <thread>
#include <mutex>
#include <chrono>
#include <cstdint>

std::mutex m;

extern "C" uint64_t fib2(uint64_t n); //rust
uint64_t fib(uint64_t n); //C++

//GCC command: g++ -o Fib.exe -L. -lfib_mgw main.cpp

auto main() -> int
{
	std::thread t1([]{
		std::lock_guard<std::mutex>lr(m);
		auto start = std::chrono::system_clock::now();
		std::cout << "Rust Library:\n\n";
		for(auto i=0; i < 41; ++i) std::cout << "Rust -> " << i << " : " << fib2(i) << std::endl;
		std::cout << "\nTime Elapsed: " << std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now() - start).count() << " ms\n";
	}),
	t2([]{
		std::lock_guard<std::mutex>lr(m);
		auto start = std::chrono::system_clock::now();
		std::cout << "================================\nC++ Library:\n\n";
		for(auto i=0; i < 41; ++i) std::cout << "C++ -> " << i << " : " << fib(i) << std::endl;
		std::cout << "\nTime Elapsed: " << std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock::now() - start).count() << " ms\n";
	});
	
	t1.join();
	t2.join();
}

program.pas

//more info: https://www.reddit.com/r/metapcj/comments/8uz5hi/self_meta_jerk_in_fact_rust_structs_are_just/
program Estudos;

uses sysutils, dynlibs;

procedure UseDLL;
type
  TMyFunc=function (n:Integer):Integer; StdCall;
var
  MyLibC: TLibHandle = dynlibs.NilHandle;
  MyFunc: TMyFunc;
  FuncResult: integer;
begin
  MyLibC := LoadLibrary('fib_rust.' + SharedSuffix);
  if MyLibC = dynlibs.NilHandle then Exit;  //DLL was not loaded successfully
  MyFunc:= TMyFunc(GetProcedureAddress(MyLibC, 'fib'));
  FuncResult:= MyFunc (5);  //Executes the function
  if MyLibC <>  DynLibs.NilHandle then if FreeLibrary(MyLibC) then MyLibC:= DynLibs.NilHandle;  //Unload the lib, if already loaded
  writeln('Result fibonacci (Lib Rust): '+InttoStr(FuncResult));
end;

procedure Main;
begin
	UseDLL;
end;

begin
  Main;
end.