Detect whether current Windows version is 32 bit or 64 bit

Question

Believe it or not, my installer is so old that it doesn\'t have an option to detect the 64-bit version of Windows.

Is there a Windows DLL call or (even better) an en

Answer 1

From a batch script:

IF PROCESSOR_ARCHITECTURE == x86 AND
   PROCESSOR_ARCHITEW6432 NOT DEFINED THEN
   // OS is 32bit
ELSE
   // OS is 64bit
END IF

Using Windows API:

if (GetSystemWow64Directory(Directory, MaxDirectory) > 0) 
   // OS is 64bit
else
   // OS is 32bit

Sources:

1. HOWTO: Detect Process Bitness
2. GetSystemWow64Directory function