Getting an: unresolved external symbol CLSID_CBMDSwitcherDiscovery using Blackmagic ATEM SDK

Question

I'm trying to develop an app to control my ATEM video switcher but am having difficulty getting started with the SDK (available over at https://www.blackmagicdesign.com/developer/product/atem)

I get the following linking error:

error LNK2001: unresolved external symbol CLSID_CBMDSwitcherDiscovery

I checked and its defined in BMDSwitcherAPI.h as below

EXTERN_C const CLSID CLSID_CBMDSwitcherDiscovery;

I think I have included all the required libraries etc as below

#include "include\BMDSwitcherAPI.h"

#include <cstdio>
#include <map>
#include <string>
#include <utility>
#include <vector>

#include <conio.h>
#include <comutil.h>
#include <atlbase.h>`

And my attempt to setup switcher discovery is direct from their sample code:

CComPtr<IBMDSwitcherDiscovery>   switcherDiscovery;
HRESULT   result;

result = switcherDiscovery.CoCreateInstance(CLSID_CBMDSwitcherDiscovery, NULL, CLSCTX_ALL);
if (result != S_OK)
{
fprintf(stderr, "A Switcher Discovery instance could not be created.  The Switcher drivers may not be installed.\n");
}

Anyone got any suggestions or ideas to help here?

As above I would expect it to return either S_OK or Null meaning that the drivers aren't installed (which they indeed are)

Answer 1

With a bit of help from Ken White all is good!

Just needed to link the Library in CMake using the lines (means you can easily change the location of the file)

SET(SWITCHERS_SDK_INCLUDE "include/BMDSwitcherAPI_i.cpp")
add_library(BMDSwitcherAPI ${SWITCHERS_SDK_INCLUDE})

And update the target_link_libraries section to inlcude the library:

target_link_libraries(... BMDSwitcherAPI ...)

It now compiles, so that is one massive hurdle overcome!