batch file - 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 environment variable that would give that information for Windows XP and Windows Vista?

One possible solution

I see that Wikipedia states that the 64-bit version of Windows XP and Windows Vista have a unique environment variable: %ProgramW6432%, so I'm guessing that'd be empty on 32-bit Windows.

This variable points to Program Files directory, which stores all the installed program of Windows and others. The default on English-language systems is C:Program Files. In 64-bit editions of Windows (XP, 2003, Vista), there are also %ProgramFiles(x86)% which defaults to C:Program Files (x86) and %ProgramW6432% which defaults to C:Program Files. The %ProgramFiles% itself depends on whether the process requesting the environment variable is itself 32-bit or 64-bit (this is caused by Windows-on-Windows 64-bit redirection).

Answer 1

To check for a 64-bit version of Windows in a command box, I use the following template:

test.bat:

@echo off
if defined ProgramFiles(x86) (
    @echo yes
    @echo Some 64-bit work
) else (
    @echo no
    @echo Some 32-bit work
)

ProgramFiles(x86) is an environment variable automatically defined by cmd.exe (both 32-bit and 64-bit versions) on Windows 64-bit machines only.