Re: 64-bit vs. 32-bit

["Chris J. Breisch" <chris dot ml at breisch dot org>]

Warren Young wrote:
> On 4/25/2014 11:26, Tom Szczesny wrote:
> > CYGWIN_NT-6.1-WOW64
>
> "WOW64" means 32-bit Windows emulated on top of 64-bit Windows.[1] This
> tells you that Cygwin is running inside that 32-bit environment.
[snip]
> You don't have to guess and hope, though. From 32-bit Cygwin:
>
> $ file /bin/ls
> /bin/ls: PE32 executable (console) Intel 80386 (stripped to external
> PDB), for MS Windows
>
> $ file /cygdrive/c/cygwin64/bin/ls
> /cygdrive/c/cygwin64/bin/ls: PE32+ executable (console) x86-64, for MS
> Windows
>
> file(1) saith sooth what what form of executable thou hast wrought.
>
> You might also find this piece enlightening: http://goo.gl/qv5ki7

That is enlightening. I have a rather different, and very non-standard 
setup, making use of $PROCESSOR_ARCHITECTURE. This environment variable 
is set in both 32-bit and 64-bit Cygwin. In the former, it's set to 
"x86" and in the latter, it's set to "AMD64".

So, I have my 64-bit Cygwin root set to C:/cygwin/AMD64, and my 32-bit 
Cygwin root set to C:/cygwin/x86. My package root for both is 
C:\cygwin\packages, and I have /home in both environments mounted on 
C:/cygwin/home.

I script all my builds, and the script I use sets the build directory 
always to build_${PROCESSOR_ARCHITECTURE}. In a similar way, my output 
files are named things like configure_${PROCESSOR_ARCHITECTURE}.out, 
make_${PROCESSOR_ARCHITECTURE}.out, etc.

But, as you mention in your SO response, I'd never dream of sharing 
/usr/local this way.

Oh, finally, I set the title of my mintty or xterm to contain 
${PROCESSOR_ARCHITECTURE} as well, so I don't forget where I am.

--
Chris J. Breisch

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