You can call functions from your C, C++, or C# plug-ins in your Unity projects.
Unity uses Emscripten to compile your sources into WebAssembly from C/C++/C# code, so you can write plug-ins in C/C++/C# code and call these functions from your Unity C# scripts.
To call functions from your JavaScript plug-ins instead, refer to Call JavaScript functions from Unity C# scripts.
To allow your Unity project to call functions from your C/C++/C# plug-in code, you need to import your plug-in into your Unity project.
Place your JavaScript plug-in files in any folder, such as Assets/JSPlugins.
If you use C++ (.cpp) to implement the plug-in, you must declare the functions with C linkage (extern “C”) to avoid name mangling issues.
The following code is an example C++ plug-in with simple functions that you can call in your Unity project.
#include <stdio.h>
extern "C" void Hello ()
{
printf("Hello, world!\n");
}
extern "C" int AddNumbers (int x, int y)
{
return x + y;
}
Note: Unity uses the Emscripten version 2.0.19 toolchain.
Use the following Unity C# code in your Unity project to call the C++ functions.
using UnityEngine;
using System.Runtime.InteropServices;
public class NewBehaviourScript : MonoBehaviour {
[DllImport("__Internal")]
private static extern void Hello();
[DllImport("__Internal")]
private static extern int AddNumbers(int x, int y);
void Start() {
Hello();
int result = AddNumbers(5, 7);
Debug.Log(result);
}
}