Re: [Boost-users] [smart_ptr] Conflict with Maya?

From: Paul Giaccone (paulg_at_[hidden])
Date: 2007-04-20 05:29:02

Michael Fawcett wrote:
> On 4/19/07, Paul Giaccone <paulg_at_[hidden]> wrote:
>   
>> Paul Giaccone wrote:
>>     
>> Hm, that made no difference... Maya is still hanging with a segmentation
>> fault when delete() is being called (not by me, incidentally) after 24
>> out of 48 frames have been processed, as if it is deciding it doesn't
>> want the node after that length of time. It still works fine in Windows.
>>     
>
> I don't think it has anything to do with Boost.  I specifically
> remember using smart_ptrs (and other Boost libraries) in conjunction
> with the Maya SDK, but I no longer have Maya installed so I can't code
> up a quick test for you.
>
> I imagine the problem is with the usage of the smart_ptrs, or lies
> elsewhere.  Can you maybe post a small sample of your usage?
>   

Hm, it's hard to cut it down to anything small, but I'll try to give 
just the minimum here. Here's the creation of the node:

    void* MyNode::creator(void)
    {
        return new MyNode();
    }

Here's the constructor:

    MyNode::MyNode(void) : success(false), error_message(""), info(0)
    {
        position.second.resize(NumPositionParameters);
        orientation.reset(new double[NumOrientationParameters]);
        previous_position_parameter.resize(NumPositionParameters);

        for (unsigned int parameter = 0; parameter != 
NumPositionParameters; ++parameter)
        {
            previous_position_parameter[parameter] = 0.0;
        }
    }

where the following are declared in the header file (as well as lots of 
other non-pointer variables):

    boost::scoped_ptr<Info> info;
    std::pair<double, std::valarray<double> > position;
    boost::shared_array<double> orientation;
    std::valarray<double> previous_position_parameter;

Info is a class that contains further shared_arrays of simple types. The 
variable info is initialised in MyNode::initialize() because the sizes 
of the arrays are not known until that point.

MyNode::compute() calls a stand-alone function, passing in some of the 
above variables. Within this function are the following definitions:

    MyModel model;
    simplex<MyModel> simplex_method(model);

The class "simplex" requires the classes it makes use of to have a 
default constructor that does not allocate any memory for objects 
pointed to by class members. The memory is allocated when the simplex 
class calls operator=, which I have defined for each class that simplex 
uses. I have used smart pointers and memory is allocated using reset() 
in each operator=() function.

The only destructor I have is for the MyNode class, which resizes the 
valarrays to 0, although these only contain doubles, so there isn't 
really anything to free.

I don't know how helpful this is, but thanks for anything you might spot 
that I have not.

Paul