_com_error, comdef.h -Catching exceptions in D3D12 - windows

Question

I'm experiencing a strange _com_error exception during graphics rendering after attempting to read data from an upload heap in the shader.
After looking up _com_error, it appears one needs to catch it like an exception:
try
{
// attempt to present the scene
System.SwapChain->Present( App.Video.Option.Set(videoSet::VERTICAL_SYNC) ? 1 : 0 );
}
catch(_com_error &x)
{
app_error( x.ErrorMessage() );
}
However, to use _com_error, I apparently need to include comdef.h, and when I include comdef.h, I get a lot of warnings and errors. The first set of the warnings/errors seem to be coming from a secondary include that is apparently included in comdef.h, C:\Windows Kits\10\Include\10.0.22621.0\um\ole2.h. The first thing I tried was to wrap my include (I'm using Visual Studio 2022):
#pragma warning(push, 0)
#include <comdef.h>
#pragma warning(pop)
However, this doesn't seem to work at all, even though it does with every other file I've ever tried to include in my project. Even with this, I still get warnings, which are treated as errors. Here are a few of them:
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(92,41): error C2220: the following warning is treated as an error
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(92,41): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(92,41): error C2491: 'OleBuildVersion': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(92,36): error C2065: 'VOID': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(94,50): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(94,50): error C2491: 'WriteFmtUserTypeStg': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(94,47): error C2065: 'IN': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(94,50): error C2146: syntax error: missing ')' before identifier 'LPSTORAGE'
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(95,34): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(95,34): error C2491: 'ReadFmtUserTypeStg': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(95,31): error C2065: 'IN': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(95,34): error C2146: syntax error: missing ')' before identifier 'LPSTORAGE'
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(100,43): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(100,43): error C2491: 'OleInitialize': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(100,40): error C2065: 'IN': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(100,43): error C2146: syntax error: missing ')' before identifier 'LPVOID'
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(107,36): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(107,36): error C2491: 'OleQueryLinkFromData': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(107,33): error C2065: 'IN': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(107,36): error C2146: syntax error: missing ')' before identifier 'LPDATAOBJECT'
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(108,38): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(108,38): error C2491: 'OleQueryCreateFromData': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(108,35): error C2065: 'IN': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(108,38): error C2146: syntax error: missing ')' before identifier 'LPDATAOBJECT'
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(113,25): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(113,25): error C2491: 'OleCreate': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(113,22): error C2065: 'IN': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(113,25): error C2059: syntax error: 'const'
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(118,27): warning C4229: anachronism used: modifiers on data are ignored
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(118,27): error C2491: 'OleCreateEx': definition of dllimport data not allowed
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(118,24): error C2065: 'IN': undeclared identifier
1>C:\Windows Kits\10\Include\10.0.22621.0\um\Ole2.h(118,27): error C2059: syntax error: 'const'
Does this have something to do with the Windows Kit I'm using? I remember trying to do this in the past, several years ago, and ran into the same exact issue, and ended up giving up trying to catch the exception.
Can anyone point out my ignorance in this situation? Any guidance would be really appreciated.

Answer 1

The problem was being caused by another header include using #undef VOID, along with removing several other defines that Windows uses.
I am being forced to include comdef.h above that include to make it work, but doing that solved my problem. If anyone else runs into similar errors, make sure you include comdef.h along with other windows headers, in case some header decides to bomb the Microsoft #define 'namespace'.