OS X Native plugin callback functions

I’ve written a small iOS plugin, and am trying to make an OS X port. In particular, the plugin is for an augmented reality application, so it uses the webcam. Having to build to a device every time I want to test something is slow, so I want to make a version that works in the editor as well (similar to Vuforia).

Since OS X/Desktop doesn’t support UnitySendMessage I’ve been trying to write a simple callback function to replace it.

My native code:

// .h 
extern "C" {
    typedef void (*callbackFunc)(const char *);
static callbackFunc cameraFrameCallback;
// .mm 
extern "C" {
    void _initWithCamera(const char * camera, GLuint texID, GLfloat width, GLfloat height, callbackFunc callback) {
        // some other init here
        cameraFrameCallback = callback;
        if (cameraFrameCallback != NULL) {
           cameraFrameCallback([@"IS THIS PRINTING?" UTF8String]);


C# code:

public delegate void cameraFrameCallback(string message);

public static void PrintLog(string message) {

private static extern void _initWithCamera(string camera, int texID, float width, float height, cameraFrameCallback callback);

public static void InitWithCamera(string camera, int texID, float width, float height) { 
    if (Application.platform == RuntimePlatform.OSXEditor) {
        _initWithCamera(camera, texID, width, height, PrintLog);

When I call the init method, I would expect the callback to get registered then send back the call to PrintLog, which would print my message in the Unity console. However, when I run this, I get nothing back. My plugin is actually running though, because I’m getting camera frames back as I would expect, just the callback function isn’t firing.

Am I missing something obvious, or does this just not work in the Editor?

For people from the future/Google:

The issue was that the Editor doesn’t reload plugins until you restart it. The code above actually works fine, but replacing my bundle with new versions when I made changes doesn’t actually cause the plugin to get reloaded, you need to replace the bundle then restart the editor.