#define BOOTUP_EXCEPTION_COMPLUS 0xC0020001
You may see
an exception with this code, or an HRESULT of this value, when trying to call
into managed code. This can happen
if you call in before the runtime has finished initializing, or after the
runtime has started shutting down.
Sometimes
it’s obvious how you run into this situation. For example, if you call into managed
code via a COM object or a marshaled delegate from your unmanaged DllMain while
processing a DLL_PROCESS_DETACH notification, then it’s quite likely that the
runtime has already shut itself down.
Other times,
it’s not so obvious. In particular,
you might see this exception being raised when a Windows message is being
processed by a thread that is pumping messages during shutdown. If there are still some managed WinProcs
registered, then a message might be dispatched to one of them. When this happens, the runtime will throw
the above exception code to indicate that managed execution is no longer
possible. The WinProcs should have
been unregistered by code listening to the AppDomain.ProcessExit event (and the
AppDomain.DomainUnload event if you have multiple AppDomains in your process).
In the case of WindowsForms, this
is handled for you automatically. But if you are building your own
windowing system, this becomes your
responsibility.
