Attempt to extract global pressure from weatherSystemService in a COM setting

[MerAB]

Hello,
I have tried to retrieve the global pressure value from P3d v4 through it's weather service by attempting to access the IWeatherSystemv430 service outside of P3d. Code for my ATL COM server and client below:

Could you please help me out with it?
Thank you

ATL COM server

// HelloWeather.cpp : Implementation of CHelloWeather

#include "stdafx.h"
#include "HelloWeather.h"

#include <Pdk.h>
#include<initpdk.h>
#include<initguid.h>
// CHelloWeather
using namespace P3D;



STDMETHODIMP CHelloWeather::getPressure(IUnknown* ppIdk, float* value)
{
    // TODO: Add your implementation code here
    PdkServices::Init((P3D::IPdk*)ppIdk);
    printf("P3d initialized");
    HRESULT hr = E_FAIL;
    if (!ppIdk)
    {
        return hr;
    }

    /*if (FAILED(static_cast<P3D::IWeatherSystemV430*>(pPdk)->GetGlobalBaroPressure()))
    {
    goto Error;
    }*/
    else
    {
        //return static_cast<P3D::IWeatherSystemV430*>(ppIdk)->GetGlobalBaroPressure();
        //*value = static_cast<P3D::IWeatherSystemV430*>(ppIdk)->GetGlobalBaroPressure();
        float ReturnValue=static_cast<P3D::IWeatherSystemV430*>(ppIdk)->GetGlobalBaroPressure();
        printf("Pressure is ");
    }
    
    return hr;
}

ATL COM client:

#include<iostream>
#include"D:\Projects\Prepar3D v4 SDK 4.3.29.25520\PDK\COMTest30_091\COMTest30_091\COMTest30_091_i.h"
#include"D:\Projects\Prepar3D v4 SDK 4.3.29.25520\PDK\COMTest30_091\COMTest30_091\COMTest30_091_i.c"

using namespace std;

int main()
{
    HRESULT         hr;
    IHelloWeather *weather = NULL;
    hr = CoInitialize(0);
    if (SUCCEEDED(hr))
    {
        hr = CoCreateInstance(CLSID_HelloWeather, NULL,
            CLSCTX_INPROC_SERVER,
            IID_IHelloWeather, (void**)&weather);

        if (SUCCEEDED(hr))
        {
            IUnknown* ptr = static_cast<IUnknown*>(weather);
            FLOAT val;
            weather->getPressure(ptr, &val);
            cout << "The global pressure is %f" <<val;
            weather->Release();
        }
        else
        {
            cout << "CoCreateInstance Failed." << endl;
        }

    }
    // Uninitialize COM
    CoUninitialize();

    return 0;
}

 

[Prepar3DGuy]

To initialize PdkServices helper you must pass pointer to IPdk interface. The only known way to get it is parameter in DLLStart function of dll add-on that Prepar3D load on startup. Memory that pointer is pointing to are in Prepar3D process address space. Your client application has its own process address space and can't access Prepar3D's. So I can't help with your example above, it will not work in that approach.