[FSUIPC read error 'Call cannot execute, link not Open']

First of all thanks for the hints.

Just to make sure, for my test I use a connection via "WideFS Client", for the code I use the SDK from here: http://www.schiratti.com/dowson.html 
The info is just to avoid that I use some wrong version or code base

Here is where it fails in read, I have just placed a single line for test purposes in my read function. I open in my object's connect function, then I call my read function:
 

FSUIPC_Read(0x0238, 3, localFsTimeRaw, &dwResult); ==> calls

if (!m_pView)
{    *pdwResult = FSUIPC_ERR_NOTOPEN; <-- returns this value
       return FALSE;
}

Now I did a second test and try to open just before, then failing with FSUIPC_ERR_MAP, so this means m_pView is 0, but the connection still exists. No idea how I can get into that status. 
 

FSUIPC_Open(SIM_ANY, &dwResult); <== fails with ERR_MAP
FSUIPC_Read(0x0238, 3, localFsTimeRaw, &dwResult);

if ((m_hMap == 0) || (GetLastError() == ERROR_ALREADY_EXISTS))
    {    *pdwResult = FSUIPC_ERR_MAP;
        FSUIPC_Close();

3rd version, I just close before I reopen and read. Everything works, even with my 

FSUIPC_Close();
FSUIPC_Open(SIM_ANY, &dwResult);
FSUIPC_Read(0x0238, 3, localFsTimeRaw, &dwResult);

Now my naive conclusion, my connection seems to get broken somewhere. If it was closed somewhere, example 2 would work. So somehow m_piew is 0, but still something is open. I am using an "all compiled" version, no libs. Compiling with VS2017, in this very case 32bit.

Maybe there is any hint, but however expect this is some odd detail. 

[FSUIPC read error 'Call cannot execute, link not Open']

Question: What is the scope of an FSUIPC_Open?
Hint: Using the C version of FSUIPC SDK with FSX:  FSUIPC 4.9.7.3 (FSX) 32 bit, my full code is attached as file.

I have a small class wrapping my FSUIPC functionality. The FSUIPC_Open itself works (returns true, DWORD result is 0)
I can also FSUIPC_READ in the same function, so far so good.

bool CFsuipc::connect(bool force) { .... DWORD result; ... if (FSUIPC_Open(SIM_ANY, &result)) ...

Now in another function (read) I rely on that opened FSUIPC connection. Still the same object in memory.

bool CFsuipc::read(CSimulatedAircraft &aircraft, bool cockpit, bool situation, bool aircraftParts) {  if (  FSUIPC_Read(0x0238, 3, localFsTimeRaw, &dwResult) &&

Now the read fails with "FSUIPC read error 'Call cannot execute, link not Open'` So somehow my open connection got lost. I can say for sure, the object is still the same. So where is the  info of the open connection stored?

Of course I could always open in the same step as I read, but I wonder why the state of the connection does not persist?

fsuipcimpl.cpp

[Ground elevation at arbitrary lat/lng position]

Cool. Just to confirm the above, we are using also just a single point grid.

[Ground elevation at arbitrary lat/lng position]

I can not exactly say, but there are already question about the function back in 2012: http://prepar3d.com/forum/viewtopic.php?t=7290

[Ground elevation at arbitrary lat/lng position]

On P3D there is a function for that (SimConnect_RequestGroundInfo, not compatible with FSX), new P3D API. For FSX I create a bogus AI object and query the position at its position (kind of hack but working). For the later I still search a way to create an invisible AI object https://www.fsdeveloper.com/forum/threads/invisible-or-very-small-ai-object.442575/

[Ground elevation at arbitrary lat/lng position]

Moved to Main Forum. Please ask questions related to FSUIPC always in Main Forum!

Is there a way to get the ground elevation for a given latitude/longitude position. I need to get the current ground elevation (representing the scenery) at a given position, which is NOT my own aircraft's position and NOT the position of another AI aircraft.

I know how to do it with FSX and P3d/simConnect, but need a similar function for FS9.
Any hint how I can do it (if possible)?

[Probelm with FSX FP folder]

Excellent, that's it. Thanks a lot!

Klaus

[Probelm with FSX FP folder]

Hi Volker,

I want to set it to an arbitrary path, not to C:\Users\my name\Documents\Flight Simulator X Files

When setting it in the path window the changed path settings gets lost - this is my problem.

Klaus

[Probelm with FSX FP folder]

I have a very similar problem with FSC 9.2. I get the message "FSX flight plan folder unspecified! Choose <Flight Simulator X Files> manually." as well. Under load/save I do set it to the correct folder (path tab). Once I switch back to the "LOAD" tab and go back to "Paths" -> same issue. The path will always be reverted to c:\users\my name\Documents.

This is how it looks in the .ini

FPPATH09=

FPPATH10=C:\Users\my name\Documents\

FPPATH11=

FSCPLANPATH=P:\FlightSimulatorAddOns\FSC9\Flightplan\FSC

SQUAWKBOXPATH=P:\FlightSimulatorAddOns\FSC9\flightplan\SquawkBox

IVAOPATH=P:\FlightSimulatorAddOns\FSC9\flightplan\IVAO

FSINNPATH=P:\FlightSimulatorAddOns\FSC9\flightplan\FSInn

I have changed it in the ini directly (P:\FlightSimulatorAddOns\FSC9\Flightplan\FSX) -> no effect. Whatever I do, after I close FSC it is always back to FPPATH10=C:\Users\my name\Documents\

The want-have-path exists, checked several times. FSC runs on a secondary LAPTOP with no FSX on it. But there is a symbolic link to FSX, which is also set in the PATHs tab. I am not talking about a shortcut, is is a real symbolic link making the FSX folder appearing as it was locally installed.