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

20 Apr 2007

      Michael Fawcett wrote:
...
On 4/19/07, Paul Giaccone  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 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