Unable to get constants from Reason.h defined

[v-tbert]

The constants used for shutdown/reboot functions are defined in reason.h and documented here:
https://docs.microsoft.com/en-us/windows/win32/shutdown/system-shutdown-reason-codes

Listing InitiateSystemShutdownEx in NativeMethods.txt works fine, but listing SHTDN_REASON_MAJOR_APPLICATION, for example, results in a build warning: Method or type "SHTDN_REASON_MAJOR_APPLICATION" not found.

What do I need to differently to import these?

Also, is there a way to automatically import them as an enum with flags attribute?

[AArnott]

This will require manual enum work.