Should I define both _WIN32 and _WIN64 in 64bit build?

windows visual-studio visual-c++ configuration 32bit-64bit
Benjamin picture Benjamin · Jul 13, 2011 · Viewed 27.8k times · Source

When we add a 64bit configuration from a 32bit project that has already existed, Visual Studio copies the 32bit configurations by default. VS even copies _WIN32
All my 64bit projects define also _WIN32 now, despite they(64bit PEs) never can run on 32bit Windows. It is very uncomfortable to me.

I'd like to remove the _WIN32 if it doesn't have any problem. I'm not sure about that.
Is it okay if I remove the _WIN32 definition?

Answer

Hans Passant picture Hans Passant · Jul 13, 2011

_WIN32 doesn't mean what you think it does. It means "I am using the Windows API". The 32 postfix was added back in the days of Windows NT 3.1 to make it distinct from the 16-bit API that was used in Windows version 3. This term has fallen out of favor because of the bitness problem. You can see this at stackoverflow.com, the [win32] tag takes you to [winapi].

Don't remove it, you are using the Windows API.

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