S-Function PWork pointers and memory allocation error

I am developing an interface between simulink and a custom c++ library using an S-Function. The purpose of my library is to solve the state of a cable at different stages when forces are applied to each end. A cable object is initialised in the mdlStart section. I set the PWork value to a pointer to this. When I dereference the PWork pointer in the Output section I am getting a Memory Allocation Error.

My code looks like this:

static void mdlStart(SimStruct *S)
{
  Line line = builder.initialise(start,end,reel_out_length,9.81,1.225);
  cout << line.node_positions() << endl; // outputs the correct positions of the line
  ssSetPWorkValue(S, 0, &line);
  Line *l = static_cast<Line *>(ssGetPWork(S)[0]);
  cout << l->node_positions() << endl; // outputs the correct positions of the line
}

static void mdlOutputs(SimStruct *S, int_T tid)
{
  Line *l = static_cast<Line *>(ssGetPWork(S)[0]);
  cout << l->node_positions() << endl; // causes memory allocation error  
}

The mdlStart function runs well, but the mdlOutputs function gives me this error:

An error occurred while running the simulation and the simulation was terminated
Caused by:
Memory allocation error. 

I am relatively new to both C++ and Simulink so there may be something obvious I am missing. Any help is greatly appreciated.

Answer 1

[Peter Armstrong]

The object I was trying to access was being created on the stack and not on the heap. Sorted now.