visual studio 2015 c++ sddl.h does not appear as external dependency - visual-studio

Question

I am trying to use the function ConvertSidToStringSid() in a Visual Studio 2015 Community, console project.
According to the msdn page
https://msdn.microsoft.com/en-us/library/windows/desktop/aa376399(v=vs.85).aspx
the requirements are:
Minimum supported client: Windows XP [desktop apps only]
Minimum supported server: Windows Server 2003 [desktop apps only]
Header: sddl.h
Library: Advapi32.lib
DLL: Advapi32.dll
I am using a Windows 10 Home, 64-bit computer. I have the *.lib and *.dll files respectively in :
C:\Program Files (x86)\Windows Kits\10\Lib\10.0.10240.0\um\x64\AdvAPI32.Lib
C:\Windows\System32\advapi32.dll
When i fill in the "#inclucde " in stdafx.h, I get no error from Intellisense. In contrast, "#include <blah.h>" gives a red wiggling underline under the 'include', and a mouse-over says 'Error: Cannot open source file "blah.h"'.
In my .cpp source file, which includes "stdafx.h", I add the code
BOOL OK ... ;
PSID owner;
char *sOwner;
OK = ConvertSidToStringSidW(owner, sOwner);
but then I get the red wiggle under ConvertSidToStringSidW.
In the solution explorer, under the project, under External dependencies there are files SCardErr.h and sdkddkver.h, but nothing, no sddl.h, between these two. (And, by the way, sddkver.h defines _WIN32_WINNT_THRESHOLD 0x0A00. Testing with IntelliSense in the editor, _WIN32_WINNT is also 0x0A00.)
When compiling, I first got an error message that the file sddl.h could not be found. I have multiple copies on the computer, and added to the "Additional include directories" for all configurations, the directory
C:\Program Files (x86)\Windows Kits\10\Include\10.0.10586.0\shared
Compiling still fails with "identifier xxx is undefined" and 'xxx': Identifier not found, from IntelliSense and Build respectively.
The header sddl.h is still not in the external dependencies. Right-clicking on the sdksddkver.h I get its full path: The newly added additional include directory. I don't know what it was before I added this include directory.
Right clicking on the include directive in stdafx.h, I can open sddl.h. The editor shows parts of the contents in a light grey color, when the contents is guarded by an #if/#ifdef directive whose argument is false. However, the function I want to use, ConvertSidToStringSid, is shown in full color.
Unsure if its a clue that the error messages say "defined" rather than "declared". In the project properties, linker, input, additional dependencies, the file advapi32.lib is listed.
What am I doing wrong?

Answer 1

I found the solution myself. The problem was that I had two projects in the same "solution", each with its own stdafx.h file. I had the wrong stdafx.h file open in the editor, and placed the #include directive in the wrong file.
-Thanks