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From: "Paul G." <pgarceau AT qwest DOT net>
Organization: Paul G.
To: cygwin-apps AT cygwin DOT com
Date: Sun, 2 Dec 2001 15:12:19 -0800
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Subject: Re: Semi-OT: (Was Re: attn: which, bzip2,gzip maintainers (was Re: some problems with setup.ini))
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Thanks Robert.

	Paul G.

> ----- Original Message -----
> From: "Paul G." <pgarceau AT qwest DOT net>
> > > I didn't know that Cygwin runs under several flavors of Unix.
> AFAIK,
> > > it's calling Win32 API functions but I could be wrong...
> >
> > hmm...is that a challenge?  Not sure how else to take it --
> >
> > You're right, of course, dear Corinna, it is calling Win32api
> functions, but afaik, that is not
> > all it does.  In fact I've forced it into doing more than that.  Most
> folks that I told about it asked,
> > "What's the point?".  The answer I typically give:  "It is fun, it is
> educational and, who knows,
> > maybe someone, somewhere wants to build Cygwin generated apps under a
> *nix or Linux
> > platform..."
> 
> I think we've got a terminology problem.
> 
> "cygwin1.dll" aka Cygwin - a runtime POSIX compatability layer. ONLY
> executes on win32 platforms - Win 95/98/ME/NT4/2K/XP. When configuring a
> gcc+binutils toolchain use pc-ix86-cygwin to target this 'platform'.
> (It's really just a different C library for win32, so 'platform is a
> little strong :}).
> "Cygwin" aka the cygwin Net distribution. A collection of open and free
> software provided in binary form along with cygwin1.dll
> 
> So Cygwin means two things :}.
> 
> ...
> > Of course, I've only been working with Cygwin since about r17, so I
> could be completely
> > wrong about this.
> > If you are wanting to cross-compile to other targets you can, can't
> you?  Or is there some
> > rule (legal or otherwise) that states Cygwin can not run on anything
> but Win32api based
> > platforms?
> 
> Cygwin the dll only works on w32api programs - because it's translating
> posix calls to win32 calls. It can be ported of course, and win64 and
> wince are both platforms that could benefit from a port of cygwin to
> them. Un*x machines won't benefit because they already have the posix
> calls natively. So the restriction to where cygwin the dll runs is
> purely technical - and can be lifted somewhat. I'd really love to see
> cygwin1.dll running under WINE for example. I think that'd be a neat
> hack.
> 
> > Please, do correct me if I am wrong.  Cygwin (not necessarily "just
> the API") is built with
> > some variation of gcc/g++ right?  Ie. the source code, for the most
> part, is written using C, C++ or
> > C/C++ language syntax, right?  (Setup.exe is, syntactically speaking,
> C/C++)
> 
> cygwin1.dll and the associated utilites are C/C++/x86assembler.
> 
> ...
> > Bottom line: It don't matter what Cygwin is targetted for as default
> build environment.
> ....................................GCC.................................
> .................
> > gcc/g++ compiled/linked source code, in standalone mode (w/no gui
> dependencies), will run on
> > Win32api based platforms, Linux based platforms (with some lib
> modifications), *nix platforms (lib > modifications) and Cray
> Supercomputers (Terraflops anyone?).
> > All a developer needs to do, in the absence of any GUI dependencies,
> is build using
> > gcc/g++ and be able to output the appropriate, platform specific,
> libraries & support.  From that
> > standpoint, gcc/g++ is about the closest thing to a multi-platform
> (universal?) C/C++ compiler I
> > have ever found.
> 
> Absolutely (with the one correction I've made in your paragraph :}).
> cygwin1.dll is newlib+lowlevelposixsupport. So on linux you have glibc +
> linux kernel + gcc toolchain, on bsd you have bsd kernel, plus the BSD C
> library + gcc toolchain, and on win32 you have
> either
> MSCVRT - MS C library + gcc toolchain
> or
> cygwin1.dll + gcc toolchain.
> 
> And of those two, one gives you POSIX, and one doesn't :}. And as a
> second comment on your last paragraph, there are many non-GUI
> dependencies - pthreads for example - that are also present to some
> extent on all of the platforms listed, which aids portability.
> 
> Rob
> 
>