* `callback`: `void (*)(void*)` - A pointer to the function to call at exit.

* `args`: `void*` - A pointer to pass to the callback at exit.

Registers exit hooks that run after the event loop has ended, but before the VM

is killed.

Callbacks are run in last-in, first-out order. AtExit takes two parameters:

a pointer to a callback function to run at exit, and a pointer to untyped

context data to be passed to that callback.

The file `addon.cc` implements AtExit below:

// addon.cc

#undef NDEBUG

#include <assert.h>

#include <stdlib.h>

#include <node.h>

namespace demo {

using node::AtExit;

using v8::HandleScope;

using v8::Isolate;

using v8::Local;

using v8::Object;

static char cookie[] = "yum yum";

static int at_exit_cb1_called = 0;

static int at_exit_cb2_called = 0;

static void at_exit_cb1(void* arg) {

Isolate* isolate = static_cast<Isolate*>(arg);

HandleScope scope(isolate);

Local<Object> obj = Object::New(isolate);

assert(!obj.IsEmpty()); // assert VM is still alive

assert(obj->IsObject());

at_exit_cb1_called++;

}

static void at_exit_cb2(void* arg) {

assert(arg == static_cast<void*>(cookie));

at_exit_cb2_called++;

}

static void sanity_check(void*) {

assert(at_exit_cb1_called == 1);

assert(at_exit_cb2_called == 2);

}

void init(Local<Object> exports) {

AtExit(sanity_check);

AtExit(at_exit_cb2, cookie);

AtExit(at_exit_cb2, cookie);

AtExit(at_exit_cb1, exports->GetIsolate());

}

NODE_MODULE(addon, init);

} // namespace demo

Test in JavaScript by running:

// test.js

var addon = require('./build/Release/addon');