Some test output: C++: function 'prototype' property is 019D7408 C++: function's GetPrototype() returned 019D740C C++: function's __proto__: 019D742C JS: T.prototype: 00D9FC30 JS: T.__proto__: 00D9FC30 JS: T.prototype.__proto__: 00D9FC30
So in C++ all pointers are different, and in JS all of them are equal :) In the JS callback, if I print the GetPrototype() value instead of the argument, I get addresses consisten with the C++ printout On Mar 14, 2:29 pm, avasilev <[email protected]> wrote: > I,m trying to write a C++ app to test these values, I print C++ > pointers and implement a js function, taking an object, and print this > object's pointer, so that I have a picture both what Js and C++. > However, I discovered a strange thing - the function's arguments, > transformer like this: *(args[0]->ToObject()) always appear as the > same pointer between function calls. If I try to print two object > arguments in the same call, these are consecutive addresses. So it > seems v8 passes different objects than the actual ones, somehow > shadowing the real object. The addresses are quite different than > these that I get in C++, which leads me tho thing they are allocated > on the stack. This all makes sense, but how is the shadowing mechanism > implemented, and is there a way to reach the original objects from > within the function? > > On Mar 13, 4:06 pm, Matthias Ernst <[email protected]> wrote: > > > > > > > > > On Tue, Mar 13, 2012 at 3:00 PM, avasilev <[email protected]> wrote: > > > Thanks, > > > I was just thinking that as there is GetPrototype() and SetPrototype() > > > for objects, which access '__proto__', there should be also for > > > 'prototype'. > > > Well, GetPrototype() has slightly different semantics, at least > > judging from the documentation WRT hidden prototypes. > > > > I'd like to use the topic to ask - what does GetPrototype() actually > > > return on a function object then? Is it func.prototype.__proto__? > > > I'd expect func.__proto__. > > In the Chrome console this evaluates as such: > > > (function() {}).__proto__ > > function Empty() {} > > > Matthias > > > > On Mar 13, 3:50 pm, Matthias Ernst <[email protected]> wrote: > > >> On Tue, Mar 13, 2012 at 2:26 PM, avasilev <[email protected]> wrote: > > >> > Hello, > > >> > Is there a way to get a function's prototype, equivalent to the > > >> > function's 'prototype' property, e.g.: > > > >> > function Func() > > >> > {} > > >> > var a = Func.prototype; > > > >> > Using Object::GetPrototype() does not do the same and returns a > > >> > different value. Setting an object's prototype via SetPrototype() to > > >> > the property value gives the desired effect of instanceof recognizing > > >> > the object as constructed by the function. Setting the prototype to > > >> > the function's GetPrototype() does not achieve this. > > >> > From the doc I don't see a way to access the "prototype" property of a > > >> > function, besides getting it as an ordinary property via func- > > >> >>Get(String::New("prototype")); > > >> > Am I missing something? > > > >> I don't think you are. Why should there be another way, apart from > > >> convenience? If JS specifies it as a property, especially not even a > > >> special one, then use the property accessor. You may of course argue > > >> that it's inconsistent with, say, Array::Length. > > > >> > Greetings > > >> > Alex > > > >> > -- > > >> > v8-users mailing list > > >> > [email protected] > > >> >http://groups.google.com/group/v8-users > > > > -- > > > v8-users mailing list > > > [email protected] > > >http://groups.google.com/group/v8-users -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users
