Subj : Re: Calling non-existent object function crashes engine
To   : sydlogan
From : Syd Logan
Date : Mon Sep 05 2005 06:11 pm

GetComponent: found a component object!
94981D9E-FC99-11D9-8BDE-F66BAD1E3F3AButton1Click got the component
Able to create a JS function for Hello!!!
*****Created the JS object for GUUID 2ABDF00B-025E-11DA-BFFE-000A27942344
2ABDF00B-025E-11DA-BFFE-000A27942344Button1Click got the object
******Hello from HelloClass C++
TypeError: anobject.Foobar is not a function

Oh joy, thanks for the tips. No more crashing, and a very sane error 
message.

On to the next challenge: ensuring that the JS object is destroyed after 
it is used (meaning what references it goes out of scope), and how to 
hook into its destruction so that I can call into the component to 
release the C++ object it wraps.

Fun stuff.

syd

Syd Logan wrote:

> 
> 
> John Bandhauer wrote:
> 
>> Syd Logan wrote:
>>
>>>     JSClass objectClass = {
>>>         name.c_str(), JSCLASS_NEW_RESOLVE,
>>>         JS_PropertyStub,  JS_PropertyStub,
>>>         JS_PropertyStub,  JS_PropertyStub,
>>>         JS_EnumerateStub,  JS_ResolveStub,
>>>         JS_ConvertStub,   JS_FinalizeStub
>>>     };
>>
>>
>>
>>
>> I'd say one mistake is in using JSCLASS_NEW_RESOLVE and passing 
>> JS_ResolveStub. I believe that JSCLASS_NEW_RESOLVE tells the engine 
>> that the resolve callback is of type JSNewResolveOp, but you are 
>> passing in a callback of type JSResolveOp. That would be bad.
> 
> 
> Does sound bad, I'll give that a try.
> 
>>
>> I'd also have to wonder if the name string you are passing is static 
>> (name.c_str()) - the engine doesn't make a copy of it. As Brendan 
>> pointed out, same story for the entire JSClass structure.
> 
> 
> Right. It's not static, it lives on the stack. But I have a place for 
> both of these, thanks for pointing out the problem.
> 
>>
>> You are either calling the wrong address if the JSClass* is not 
>> pointing to data that doesn't change, or you are screwing up the stack 
>> on return from JS_ResolveStub.
>>
> 
>>
>> John.
> 
>

.