RFC: Cygwin 64 bit?

Corinna Vinschen corinna-cygwin@cygwin.com
Sun Jun 26 11:45:00 GMT 2011

Hi guys,

I'm not sure if you agree, but as far as I can see, 32 bit systems are
more and more reduced to a niche market, namely Netbooks and other very
small systems.  On the Desktop, 32 bit is declining fast, in the server
segment it's practically dead.

Given this, I'm wondering how much future Cygwin has if we stick to
32 bit.  I think it will be pretty limited.  In fact, we're probably
rather late in the game.

Lately I read a bit more about how 32 and 64 bit processes can interact
with each other on Windows, and it seems we could come up with a 64 bit
DLL which shares all important information with its 32 bit counterpart,
so that we could run 64 and 32 bit processes in parallel on a 64 bit
system acting as a single system.  This would be especially important,
given the fact that 64 bit Cygwin applications will be pretty rare in
the beginning.

As far as I can see what we have to do in about this order is

- Discuss certain basics.  This is probably the most crucial step.
  For instance:

  - What name should the 64 bit DLL have?
  - Where should 64 bit binaries and libs go?
  - Do we define "long" as 32 bit or 64 bit type?
  - What defines should a 64 bit Cygwin compiler define?
  - What Windows headers and link libs do we use?

- Create a x86_64-pc-cygwin cross toolchain.

- Create x86_64 replacements for x86 code and in general try to make the
  Cygwin code 64 bit clean where it isn't so far.

- Decide how we can integrate 64 bit stuff into the distro.  Will we have
  a 32 bit and a distinct 64 bit distro?  Or, should we stick to a single
  distro?  If so, how do we separate 64 and 32 bit stuff?  What is the
  best package layout?

- Change setup to allow installation of 64 bit stuff on 64 bit systems.

This is a big project which can only work if we have help and support
from the community.  Before we can even contemplate to start discussing,
I would like to learn:

- How much interest do you have in a 64 bit Cygwin?

- How much interest do you have to help to make 64 bit Cygwin real?

- What part of the project would most interest you to help?  Coding
  Cygwin?  Documentation?  Setup?  Toolchain?  You name it.

Thanks in advance,

Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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