I have a C# app I'm writing that will be run on both Win32 and Win64
platforms. I'm limited to XP, 2003, Vista and beyond, and don't have to
support 9x/2000/NT.

This application calls other, external tools to do its work, and which
tool should be used varies depending on the platform and whether it is
64 bit or 32 bit.

Things I perceive as dead ends:

IsWow64Process. This seems to be NOT what I want, since I actually
don't care if the C# app is running in 32 bit mode or 64 bit mode --
it's irrelevant to me. What I care about is  "Am I running on a
Win32-only platform, or a Win64 capable platform?"

GetNativeSystemInfo. This tells me what the physical hardware is, but
that doesn't tell me what OS is running on it.

If it comes to that, I'll write a command line tool in C++ that does
nothing but answer this question for me. But I thought I'd make sure
there was no other way before I resorted to this.

Is there a clean way to determine if I'm running on a 64-bit OS from
C#?

I will try to read responses to the group, but email CC's are greatly
appreciated.

Stew