using std::vector<double> inside mexfunction()

hi,

 i have the following

----myfunction.cpp------
#include<mex.h>
#include<math.h>
#include<matrix.h>
#include<stdio.h>
#include "mydllfunctionheader.h"
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) 
{

    mystruct  XXX;
    XXX.a=0;
    XXX.b.resize(10,0.);
    mydllfunction(XXX);

} 

----mydllfunctionheader.h----
#include <vector>
#include <map>
struct mystruct
{
  double a;
  std::vector<double> b;
}

__declspec(dllexport) int __cdecl
mydllfunction(mystruct  XXX);

----------------------

problem is inside the mexfunction i make XXX.b to be of size 10 vector. but in the debug mode when i enter the mydllfunction the vector b gets messed up. any doubles (such as variable "a") are okay but any vectors are not okay.

Can anyone please comment on what is going on.

also i cannot have extern "C" before my _declspec. becuase though in the simple example i provide above i am returning int in the actual case i will be returning an complex object.

thanks in advance