[英]C++ Calling an Uninitialized variable
我正在查看v8中的以下源代码,并且handle_scope对象使我感到困惑。 似乎在初始化之前就已调用它。 该文档指定它是堆栈分配的对象。 是否为此对象自动调用默认构造函数?
// Utility function that wraps a C++ http request object in a
// JavaScript object.
Handle<Object> JsHttpRequestProcessor::WrapMap(map<string, string>* obj) {
// Handle scope for temporary handles.
HandleScope handle_scope;
// Fetch the template for creating JavaScript map wrappers.
// It only has to be created once, which we do on demand.
if (map_template_.IsEmpty()) {
Handle<ObjectTemplate> raw_template = MakeMapTemplate();
map_template_ = Persistent<ObjectTemplate>::New(raw_template);
}
Handle<ObjectTemplate> templ = map_template_;
// Create an empty map wrapper.
Handle<Object> result = templ->NewInstance();
// Wrap the raw C++ pointer in an External so it can be referenced
// from within JavaScript.
Handle<External> map_ptr = External::New(obj);
// Store the map pointer in the JavaScript wrapper.
result->SetInternalField(0, map_ptr);
// Return the result through the current handle scope. Since each
// of these handles will go away when the handle scope is deleted
// we need to call Close to let one, the result, escape into the
// outer handle scope.
return handle_scope.Close(result);
}
是的,该对象是默认初始化的,这意味着将调用其默认构造函数。 就像您声明一个std::string
:
std::string str;
该str
仍已初始化。
仅对于非类类型,默认初始化意味着没有初始化。
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