winapi - Is there a Windows API call that will tell me if I'm running on a 64-bit OS?

Question

Is there a Windows API call that will tell me if I'm running on a 64-bit OS? I have some legacy c++ code that makes a call to GetVersionEx to fill in a OSVERSIONINFO structure, but that only tells me (AFAIK) the OS (Vista, V7, etc.), but not the processing architecture. I can hack around this by simply looking for the existence of "C:Program Files (x86)...", but this seems ugly. I'm sure there must be an API to return this info.

Answer 1

IsWow64Process might be what you are looking for.