RFC: Cygwin 64 bit?

Andy Koppe andy.koppe@gmail.com
Mon Jun 27 08:17:00 GMT 2011


On 27 June 2011 08:25, Corinna Vinschen wrote:
> On Jun 27 06:49, Andy Koppe wrote:
>> On 27 June 2011 04:08, JonY wrote:
>> > I was thinking that 64bit Cygwin will be installed in a completely
>> > separate directory so there is no chance in clobbering 32bit Cygwin
>> > DLLs, like a parallel 1.5/1.7 install.
>>
>> A clean cut would be ideal, but I fear it would also greatly delay the
>> project, because a large number of packages would need to be ported
>> before the 64-bit distro would become viable for users. Supporting
>> both 32-bit and 64-bit processes and having them interact seemlessly
>> could avoid that.
>
> Just as on 64 bit Linux.  And just as on Linux there will be
> applications which won't be ported to 64 bit for quite some time.
>
> AFAICS, the two DLLs can simply share all data and act as a unity.
> There would be not much of a difference, except for running on a
> different CPU, kind of.  To the best of my knowledge there's no
> reason to keep 64 and 32 bit separate.
>
>> This doesn't meant that Cygwin 2 (to coin a handle) still has to be
>> installable on 32-bit systems, i.e. that 64-bit applications wouldn't
>> still need 32-bit versions as well.
>
> There's still 32 bit Cygwin.   I don't think we can neglect that.
> And, as I said, there's no reason to do that.
>
>> The situation is different with libraries, where the 32-bit versions
>> would need to stick around as long as there are still 32-bit
>> applications using them. Could this be handled with ABI bumps, so for
>> example libncurses10 would remain 32-bit, but libncurses11 would be
>> 64-bit? I think this would fit into the existing packaging
>> infrastructure.
>
> That's not an option, IMO.

I'm probably missing something obvious, but why?


> What speaks against doing it the Linux way,
> keeping 32 bit libs in {/usr}/lib and 64 bit libs in {/usr}/lib64?

The prefix hackery that I presume is needed for this. Granted, since
Linux does it this way, it should already exist in most cases.


> In addition we will probably need a {/usr}/bin64, due to the $PATH
> issue

That one seems more hairy than lib64, unless others have this as well?

Andy



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