Fw: [Axiom-developer] Re: GCL on Cygwin for Axiom

[Mike Thomas]

My first attempt bounced from axiom-developer even though the other went
through??

----- Original Message -----
From: "Mike Thomas" <address@hidden>
To: <address@hidden>; <address@hidden>
Cc: <address@hidden>; <address@hidden>; <address@hidden>;
<address@hidden>
Sent: Thursday, November 21, 2002 9:25 AM
Subject: Re: [Axiom-developer] Re: GCL on Cygwin for Axiom


> Hi there.
>
> Below please find an attempt to discourage the development of a Cygwin
> version of GCL and in the interests of intellectual freedom, "paper
napkin"
> instructions on how to go about it if you decide to do so.
>
> > re: trivial port of gcl....
> >
> > Not at all. Since gcl uses the native loader formats there is
> > always an issue of developing a loader that understand the
> > format for a particular platform. Bill and I struggled with
> > this whole issue on AIX for the RS/6000.
>
>
> REBUTTAL
>
> Fortunately, Cygwin and Mingw32 use the same binary format and GNU
binutils
> (modulo Cygwin Unix emulation) so as far as I know that is not a problem
> here.
>
>
> WHY NOT TO DO A GCL CYGWIN PORT
>
> I think that a Cygwin version will not buy you very much functionality and
> is likely to be slower where Unix emulation is used.  You will also have
the
> usual conflicts between Cygwin application paths and Windows paths, drives
> mounted as text mode etc.
>
> More importantly, it will also be yet another branch of the code that
> someone will have to maintain and package, which is a problem as it stands
> because very few people seem to be interested in supporting GCL on
Windows.
> Note that most of the inherently difficult outstanding problems on Mingw32
> are going to be the same on Cygwin - BFD linking comes to mind.
>
> On a final note, it might be worthwhile checking out ECL (
> http://ww.telent.net/cliki/ECL  ), which allegedly supports Cygwin.  ECL
is
> very closely related to GCL/AKCL.
>
>
> HOW TO START A CYGWIN PORT OF GCL
>
> Having said that, off the top of my head here is what I believe you would
> need to do to port GCL to Cygwin:
>
> - Get the latest source from CVS (see the GCL web site
> http://savannah.gnu.org/projects/gcl/  )
>
> - Copy the files "h/mingw.*" to "h/cygwin.*".  Check that they make sense
in
> the context of Cygwin and minimise modifications until you have found a
> specific reason for doing so when trying to compile and run GCL.
>
> - Grep the source for __MINGW32__ and WIN32 and check that the code does
> what you would want then add the __CYGWIN__ macro in places where Cygwin
> specific changes are required.  I have left the road open for Cygwin and
> other Windows compilers through the convention that _WIN32 denotes code
> which will work under any Windows compiler, and in other cases the
compiler
> specific macro is used.
>
> - Ensure that file opening is forced to binary mode so that when object
> loading occurs the object files are interpreted as binary rather than
> textual data (see "o/main.c":
> ...
> #ifdef _WIN32
>  _fmode = _O_BINARY;
> #endif
> ...
> ie if Cygwin doesn't support _fmode you'll have to find another way.
>
> - check that configure.in does the right thing for Cygwin.
>
> - try building and make further plans based on the outcome.
>
>
>
> Cheers and best of luck
>
> Mike Thomas.
>
>