从node.js本地代码调用回调 [英] Calling callback from node.js native code

问题描述

我使用c ++为node.js编写一个附件。

I'm writing an add-on for node.js using c++.

这里有一些代码片段：

class Client : public node::ObjectWrap, public someObjectObserver {
public:
  void onAsyncMethodEnds() {
    Local<Value> argv[] = { Local<Value>::New(String::New("TheString")) };
    this->callback->Call(Context::GetCurrent()->Global(), 1, argv);
  }
....
private:
  static v8::Handle<v8::Value> BeInitiator(const v8::Arguments& args) {
    HandleScope scope;
    Client* client = ObjectWrap::Unwrap<Client>(args.This());

    client->someObject->asyncMethod(client, NULL);

    return scope.Close(Boolean::New(true));        
  }      

  static v8::Handle<v8::Value> SetCallback(const v8::Arguments& args) {
    HandleScope scope;
    Client* client = ObjectWrap::Unwrap<Client>(args.This());
    client->callback = Persistent<Function>::New(Handle<Function>::Cast(args[0]));

    return scope.Close(Boolean::New(true));
  }

我需要保存一个javascript函数作为回调函数调用它。
Client类是另一个对象的观察者，javascript回调应该从onAsyncMethodEnds调用。
不幸的是，当我调用函数BeInitiator时，我在回调之前收到Bus error：10错误Call（）

I need to save a javascript function as callback to call it later. The Client class is an observer for another object and the javascript callback should be called from onAsyncMethodEnds. Unfortunately when I call the function "BeInitiator" I receive "Bus error: 10" error just before the callback Call()

>

推荐答案

您不能从另一个线程 - >调用。 JavaScript和Node是单线程的，试图从另一个线程调用一个函数等于试图一次运行两个线程的JS。

You cannot ->Call from another thread. JavaScript and Node are single threaded and attempting to call a function from another thread amounts to trying to run two threads of JS at once.

你应该重新工作你的代码不要这样做，或者你应该阅读 libuv 的线程库。它提供 uv_async_send ，可用于在单独的线程中触发主JS循环中的回调。

You should either re-work your code to not do that, or you should read up on libuv's threading library. It provides uv_async_send which can be used to trigger callback in the main JS loop from a separate thread.

docs here： http://nikhilm.github.io/uvbook/threads.html

There are docs here: http://nikhilm.github.io/uvbook/threads.html

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