Ruby on Windows CE & Pocket PC

There is already a version of Ruby for the Pocket PC and a 'wince' directory in the Ruby source package, so you can, in theory, build it yourself. However, getting it working is easier said than done; it relies on Microsoft Embedded Visual C++ and the Windows Mobile / Pocket PC SDK toolkit.
Even once you've got those installed and working it really doesn't want to play :-(
Just look at all the newsgroup postings that complain about it:

http://www.ruby-forum.com/topic/50260
http://www.ruby-forum.com/topic/31143
http://www.ruby-forum.com/topic/48735
http://www.ruby-forum.com/topic/58497
http://www.ruby-forum.com/topic/57994

Even using the pre-compiled version from the Japanese site, if it runs on your device (I tested three, it worked on one), there are issues with string handling

Efforts Abanded: Jan, 2009
Without any updates for such a long time I felt it time to say that I have abandoned this project.
My efforts were continually bumping up against the memory limits on such small devices and the lack of a relative filesystem makes testing existing code *extremely* annoying and time consuming.
Work pressures have stopped me from working any further on the codebase and patches and I unfortunately no longer have the desire to persue this any further in my personal time. I have uploaded the last patch I made against Ruby 1.8.6-p114. Hopefully someone else will find it useful. It's in the download section here.

Update: 1st Mar, 2008
Did a little bit more work during the evenings this week. Seems to be some problems with Gem that I can't work out. Having got very close to a working install of Rails I'm now spending time porting the regression tests included in the ruby source code to work on Windows CE (mostly relative 'require' path problems). See here for more info.
Sockets work in the latest 240208 -O3 build below :-)

Update: 24th Feb, 2008 (fourth time is a charm!)
One last post until I sign off for the weekend.
Sockets work in the latest 240208 -O3 build below :-)

Update: 24th Feb, 2008 (third time today!)
One final build for the weekend (check -O3 optimised, this time which does seem to make it a little quicker. Try running "ruby /ruby/bench.rb" - this the routine listed here.

Update: 24th Feb, 2008 (second time today!)
Another build (check here for the files), this time I think I've solved the socket extension problem, well it loads when you do a 'require' now... as a bonus Gems now installs and works! Have a look!.

Update: 24th Feb, 2008
I've created a patch against my modified Ruby source code, so it should be a lot easier to build your own Ruby/WinCE/ARM binaries now. I will do a bit more testing before releasing it, as it needs an error library from CEGCC project, but it does look promising.

Let's get started..

The Theory:
The theory behind this is that building Ruby as a native 'Posix' application we don't need to get into all of the hassle with the Microsoft tools, and, hopefully, we can solve that horrible wince::strerror problem that seems to plague the natice Windows CE build.

Before we start...
This is sounding like Blue Peter! Stay with me though... Anyway, this guide presumes you are familiar with either Cygwin, the Unix-like compatability suite of programs for Windows, or an x86 flavour of Linux. The process will work for other Unix environments, but you will need to build some of the tools used in the process yourself.
If you have no experience with those environments then this guide is not for you. However, I do have a pre-built Ruby binaries for you to test on your Windows Mobile or Pocket PC device. Check them out here.

Required 'Stuff':
- The normal GNU development toolchain (gcc, make, yacc etc..)

- The CEGCC Project cross-compilation toolchain. Either Cygwin or Linux version, depending on your operating system. You do not need the mingw32 version as we will be building for Posix environment, not a Win32 CE environment.

- The Ruby source code release (this process is written for 1.8.6-p111, but should be applicable to subsequent releases).

- A working Ruby installation on your own machine. This is needed to automatically construct some of the makefiles during the build process, obviously if you're compiling Ruby for a different architecture the binary you create won't run on your computer!

- Some sort of console program to run on your Pocket PC device. Microsoft offers the Windows Mobile Powertoys for Pocket PC 2003, or you could use this version of PocketConsole which works on both Pocket PC 2003 and Windows Mobile 5+.

- Presumably, some sort of Pocket PC or Windows Mobile device powered by an ARM or Xscale processor. Either a physical device, or you can use the emulator from Microsoft.

Installing the Tools:
On my system I installed the CEGCC toolchain in the following location:
/exportATA/development/wince/cegcc

Ruby source is unpacked into:
/exportATA/development/wince/src/ruby-1.8.6-p111

All the following commands assume those locations, you will need to alter any paths to suit your environment.

Setting up the dev Environment:
I have a bunch of aliases in a file (crosscompile.config) in case the configure script doesn't detect everything quite correctly, download this and put it one level above your Ruby source directory. Do a source crosscompile.config before running configure.

You'll have to set a few LDFLAGS and CFLAGS to get Ruby to build successfully. This is the configure command that I ran:
CC=arm-wince-cegcc-gcc \
CPP=arm-wince-cegcc-cpp \
CPPFLAGS="-D_LINUX_SOURCE_COMPAT" \
LIBS="-L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib -I/exportATA/development/wince/cegcc/arm-wince-cegcc/include" \
LDFLAGS="-L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib" \
ac_cv_func_getpgrp_void=yes \
ac_cv_func_setpgrp_void=yes \
ac_cv_sizeof_long_long=8 \
ac_cv_func_memcmp_clean=yes \
ac_cv_func_memcmp_working=yes \
./configure \
--disable-ipv6 \
--target=arm-wince \
--host=arm-wince \
--with-static-linked-ext \
--disable-shared \
--prefix=/ruby \
-C

 The ac_cv lines are required, otherwise the configure script actually tries to check that the 'setpgrp' function works, which doesn't make much sense when you're building for a different architecture! The best solution I suppose, would be for someone to put a check in the configure script so that those tests are not run if it detects that we are cross compiling.
Assuming that the configure process completes ok, then we now need to edit the main Ruby makefile to use our own ruby installation - we can't continue if we don't do this as we will get errors referring to a missing ruby:
$ make
make: miniruby.exe: Command not found
make: *** [.rbconfig.time] Error 127

 Change the Makefile so that MINIRUBY is set to your actual local Ruby interpreter, e.g. MINIRUBY= /usr/local/bin/ruby

Compiling Ruby - Part 1 - miniruby:
At this point if you try to build the miniruby binary you will get something like this:
$ make miniruby
rbconfig.rb updated
arm-wince-cegcc-gcc -g -O2 -DRUBY_EXPORT -I. -I. -D_LINUX_SOURCE_COMPAT -c array.c
...
...
arm-wince-cegcc-gcc -g -O2 -DRUBY_EXPORT -I. -I. -D_LINUX_SOURCE_COMPAT -c dmyext.c
arm-wince-ar rcu libruby-static.a array.o bignum.o class.o compar.o dir.o dln.o enum.o error.o eval.o file.o gc.o hash.o inits.o io.o marshal.o math.o numeric.o object.o pack.o parse.o process.o prec.o random.o range.o re.o regex.o ruby.o signal.o sprintf.o st.o string.o struct.o time.o util.o variable.o version.o crypt.o flock.o dmyext.o
arm-wince-cegcc-gcc -g -O2 -DRUBY_EXPORT -I. -I. -D_LINUX_SOURCE_COMPAT -c main.c
arm-wince-cegcc-gcc -g -O2 -DRUBY_EXPORT -L. -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib main.o libruby-static.a -lm -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib -I/exportATA/development/wince/cegcc/arm-wince-cegcc/include -o miniruby.exe
Info: resolving _CRT_MT by linking to __imp__CRT_MT (auto-import)
Info: resolving environ by linking to __imp_environ (auto-import)
Info: resolving __ctype_ptr by linking to __imp___ctype_ptr (auto-import)
libruby-static.a(io.o): In function `pipe_open':
/exportATA/development/wince/zipped/ruby-1.8.6-p111/io.c:3113: undefined reference to `fork'
libruby-static.a(process.o): In function `get_ppid':
/exportATA/development/wince/zipped/ruby-1.8.6-p111/process.c:165: undefined reference to `getppid'
libruby-static.a(process.o): In function `rb_f_fork':
/exportATA/development/wince/zipped/ruby-1.8.6-p111/process.c:1288: undefined reference to `fork'
libruby-static.a(process.o): In function `rb_proc_exec':
/exportATA/development/wince/zipped/ruby-1.8.6-p111/process.c:1063: undefined reference to `execl'
libruby-static.a(process.o): In function `rb_f_system':
/exportATA/development/wince/zipped/ruby-1.8.6-p111/process.c:1533: undefined reference to `fork'
collect2: ld returned 1 exit status
make: *** [miniruby.exe] Error 1

 The problem is that CEGCC gives us a 'mostly' Posix compatible interface, but it is missing some system calls under Windows CE, notably; 'fork', 'execl' and 'getppid'. But it does have 'vfork' and 'execv'.

Patching
You will need to patch process.c and io.c as follows:

diff patched_process.c process.c
165c165
< return INT2FIX(0);
---
> return INT2FIX(getppid());

1063c1063
< execv("/bin/sh", str);
---
> execl("/bin/sh", "sh", "-c", str, (char *)NULL);

1288c1288
< switch (pid = vfork()) {
---
> switch (pid = fork()) {

1533c1533
< pid = vfork();
---
> pid = fork();

diff patched_io.c io.c
3113c3113
< switch ((pid = vfork())) {
---
> switch ((pid = fork())) {

 That should get you a shiny miniruby binary:
$ make miniruby
arm-wince-cegcc-gcc -g -O2 -DRUBY_EXPORT -L. -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib main.o libruby-static.a -lm -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib -I/exportATA/development/wince/cegcc/arm-wince-cegcc/include -o miniruby.exe
Info: resolving _CRT_MT by linking to __imp__CRT_MT (auto-import)
Info: resolving environ by linking to __imp_environ (auto-import)
Info: resolving __ctype_ptr by linking to __imp___ctype_ptr (auto-import)
$ ls -l miniruby.exe
-rwxr-xr-x 1 megatron users 1903849 2008-02-23 14:12 miniruby.exe
$ file miniruby.exe
miniruby.exe: MS-DOS executable PE for MS Windows 32-bit

 Reducing file size
If you're happy with just a miniruby executable, you can strip the file to reduce the size:
$ arm-wince-cegcc-strip miniruby.exe
$ ls -l miniruby.exe
-rwxr-xr-x 1 megatron users 641536 2008-02-23 14:16 miniruby.exe

Compiling Ruby - Part 2 - ruby and extensions:
If you run make now, then it should start building any of the extensions you have chosen I have not investigated all of the extensions, but most appear to build without issue. However there are several that do not build:

ext/dl
make[1]: Entering directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111/ext/dl'
Generating call.func
void
char
short
long
float
double
arm-wince-cegcc-gcc -I. -I../.. -I../../. -I../.././ext/dl -DHAVE_WINDOWS_H -DHAVE_GETLASTERROR -DHAVE_FREELIBRARY -D_LINUX_SOURCE_COMPAT -I. -g -O2 -fno-defer-pop -fno-omit-frame-pointer -c sym.c
arm-wince-cegcc-gcc -I. -I../.. -I../../. -I../.././ext/dl -DHAVE_WINDOWS_H -DHAVE_GETLASTERROR -DHAVE_FREELIBRARY -D_LINUX_SOURCE_COMPAT -I. -g -O2 -fno-defer-pop -fno-omit-frame-pointer -c handle.c
handle.c: In function 'rb_dlhandle_initialize':
handle.c:66: warning: passing argument 1 of 'LoadLibraryW' from incompatible pointer type
handle.c: In function 'rb_dlhandle_sym':
handle.c:168: warning: passing argument 2 of 'GetProcAddressW' from incompatible pointer type
handle.c:182: warning: passing argument 2 of 'GetProcAddressW' from incompatible pointer type
Generating callback.func
Generating cbtable.func
arm-wince-cegcc-gcc -I. -I../.. -I../../. -I../.././ext/dl -DHAVE_WINDOWS_H -DHAVE_GETLASTERROR -DHAVE_FREELIBRARY -D_LINUX_SOURCE_COMPAT -I. -g -O2 -fno-defer-pop -fno-omit-frame-pointer -c dl.c
In file included from /exportATA/development/wince/cegcc/bin/../lib/gcc/arm-wince-cegcc/4.1.0/../../../../arm-wince-cegcc/lib/../include/w32api/windows.h:51,
from dl.h:25,
from dl.c:8:
/exportATA/development/wince/cegcc/bin/../lib/gcc/arm-wince-cegcc/4.1.0/../../../../arm-wince-cegcc/lib/../include/w32api/winbase.h:1875: error: 'OpenFile' redeclared as different kind of symbol
../../rubyio.h:31: error: previous declaration of 'OpenFile' was here
dl.c: In function 'rb_io_to_ptr':
dl.c:554: error: 'fptr' undeclared (first use in this function)
dl.c:554: error: (Each undeclared identifier is reported only once
dl.c:554: error: for each function it appears in.)
make[1]: *** [dl.o] Error 1
make[1]: Leaving directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111/ext/dl'
make: *** [all] Error 1

 The problem is the existing definition of OpenFile in the CEGCC system headers; I'm not sure what to do here, we can do a #undefine OpenFile in rubyio.h and change the function name to something else, such as new_OpenFile, but I'm unsure how much of an impact that will have on the rest of Ruby. I think that's an exercise left to a later date. For now I just removed the ext/dl directory; I don't think this is an issue unless you are using Ruby to link into libraries under Windows CE.

ext/socket
compiling socket
make[1]: Entering directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111/ext/socket'
arm-wince-cegcc-gcc -I. -I../.. -I../../. -I../.././ext/socket -DHAVE_ARPA_INET_H -DHAVE_SOCKADDR_STORAGE -DHAVE_NETINET_TCP_H -DHAVE_INET_NTOA -DHAVE_INET_ATON -DHAVE_GETSERVBYPORT -DHAVE_TYPE_SOCKLEN_T -DHAVE_SYS_UIO_H -DHAVE_SOCKET -DHAVE_GETHOSTNAME -I. -D_LINUX_SOURCE_COMPAT -g -O2 -c socket.c
In file included from socket.c:73:
addrinfo.h:162: error: conflicting types for 'gai_strerror'
/exportATA/development/wince/cegcc/bin/../lib/gcc/arm-wince-cegcc/4.1.0/../../../../arm-wince-cegcc/include/netdb.h:461: error: previous declaration of 'gai_strerror' was here
make[1]: *** [socket.o] Error 1
make[1]: Leaving directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111/ext/socket'
make: *** [all] Error 1

 Ok, so where is gai_strerror used?...

$ grep gai_strerror ext/socket/*
ext/socket/addrinfo.h:extern char *gai_strerror __P((int));
ext/socket/extconf.rb: (void)gai_strerror(gaierr);
ext/socket/getaddrinfo.c:gai_strerror(ecode)
ext/socket/socket.c: rb_raise(rb_eSocket, "getnameinfo: %s", gai_strerror(error));
...
...
ext/socket/socket.c: rb_raise(rb_eSocket, "getnameinfo: %s", gai_strerror(error));

 So lets patch that defintion of gai_strerror by undefining gai_strerror and defining it as something else. Edit ext/socket/addrinfo.h
so that:
extern char *gai_strerror __P((int));

 becomes:
#undef gai_strerror
#define gai_strerror new_gai_strerror
extern char *gai_strerror __P((int));

 Now let's run make again:
compiling socket
make[1]: Entering directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111/ext/socket'
arm-wince-cegcc-gcc -I. -I../.. -I../../. -I../.././ext/socket -DHAVE_ARPA_INET_H -DHAVE_SOCKADDR_STORAGE -DHAVE_NETINET_TCP_H -DHAVE_INET_NTOA -DHAVE_INET_ATON -DHAVE_GETSERVBYPORT -DHAVE_TYPE_SOCKLEN_T -DHAVE_SYS_UIO_H -DHAVE_SOCKET -DHAVE_GETHOSTNAME -I. -D_LINUX_SOURCE_COMPAT -g -O2 -c getaddrinfo.c
getaddrinfo.c:246: error: static declaration of 'inet_pton' follows non-static declaration
/exportATA/development/wince/cegcc/bin/../lib/gcc/arm-wince-cegcc/4.1.0/../../../../arm-wince-cegcc/include/arpa/inet.h:60: error: previous declaration of 'inet_pton' was here
make[1]: *** [getaddrinfo.o] Error 1
make[1]: Leaving directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111/ext/socket'
make: *** [all] Error 1

 Argh... more previous declerations!. Looking at getaddrinfo.c, line 246 however, shows that 'inet_pton' is only defined here if the compiler flag -DHAVE_INET_PTON is not set. Seems like we should set that flag and try again - but don't!... even though inet_pton is defined in the CEGCC headers, there are no corresponding symbols in the provided libc.a file:
/exportATA/development/wince/cegcc/arm-wince-cegcc/lib $ arm-wince-cegcc-nm libc.a | grep inet
U inet_aton
inet_aton.o:
00000000 T inet_aton
inet_lnaof.o:
00000000 T inet_lnaof
inet_mkadr.o:
00000000 T inet_makeaddr
inet_net.o:
00000000 T inet_network
inet_netof.o:
00000000 T inet_netof
inet_ntoa.o:
00000408 T __MS_inet_addr
000007e4 T __MS_inet_ntoa
00000af4 T inet_addr
00000ab4 T inet_ntoa
U inet_ntoa

 So if we just set the compiler flag we'd end up with unresolved symobls when it came to linking the Ruby binary right at the end (been there, got the t-shirt!).
We will need to redfine it locally, as we did for addrinfo.c:
So in getaddrinfo.c, change:
inet_pton(af, hostname, pton)

 ...to:
#undef inet_pton
#define inet_pton new_inet_pton inet_pton(af, hostname, pton)
 You'll need to do a similar change change the definition of inet_ntop to new_inet_ntop in getnameinfo.c:
So in getnameinfo.c, change:
static const char *
inet_ntop(af, addr, numaddr, numaddr_len)

 ...to:
#undef inet_ntop
#define inet_ntop new_inet_ntop
static const char *
inet_ntop(af, addr, numaddr, numaddr_len)

 Final make?
What happens if we run make one last time?...
LIBRUBY_SO_UPDATE=$(LIBRUBY_EXTS)
SETUP=ext/Setup
EXTOBJS=ext/extinit.o ext/bigdecimal/bigdecimal.a ext/digest/digest.a ext/digest/bubblebabble/bubblebabble.a ext/digest/md5/md5.a ext/digest/rmd160/rmd160.a ext/digest/sha1/sha1.a ext/digest/sha2/sha2.a ext/enumerator/enumerator.a ext/etc/etc.a ext/fcntl/fcntl.a ext/io/wait/wait.a ext/nkf/nkf.a ext/pty/pty.a ext/racc/cparse/cparse.a ext/sdbm/sdbm.a ext/socket/socket.a ext/stringio/stringio.a ext/strscan/strscan.a ext/syck/syck.a ext/thread/thread.a
EXTLDFLAGS=-L'.' -L. -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib
making ruby.exe
make[1]: Entering directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111'
arm-wince-cegcc-gcc -g -O2 -DRUBY_EXPORT -L. -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib -L'.' -L. -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib main.o ext/extinit.o ext/bigdecimal/bigdecimal.a ext/digest/digest.a ext/digest/bubblebabble/bubblebabble.a ext/digest/md5/md5.a ext/digest/rmd160/rmd160.a ext/digest/sha1/sha1.a ext/digest/sha2/sha2.a ext/enumerator/enumerator.a ext/etc/etc.a ext/fcntl/fcntl.a ext/io/wait/wait.a ext/nkf/nkf.a ext/pty/pty.a ext/racc/cparse/cparse.a ext/sdbm/sdbm.a ext/socket/socket.a ext/stringio/stringio.a ext/strscan/strscan.a ext/syck/syck.a ext/thread/thread.a -lruby-static -lm -L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib -I/exportATA/development/wince/cegcc/arm-wince-cegcc/include -o ruby.exe
Info: resolving _CRT_MT by linking to __imp__CRT_MT (auto-import)
Info: resolving __ctype_ptr by linking to __imp___ctype_ptr (auto-import)
Info: resolving environ by linking to __imp_environ (auto-import)
ext/socket/socket.a(getaddrinfo.o): In function `get_addr':
/exportATA/development/wince/zipped/ruby-1.8.6-p111/ext/socket/getaddrinfo.c:620: undefined reference to `__h_errno_location'
collect2: ld returned 1 exit status
make[1]: *** [ruby.exe] Error 1
make[1]: Leaving directory `/exportATA/development/wince/zipped/ruby-1.8.6-p111'
make: *** [all] Error 2

Try as I might, I just cannot figure this one out... I'm pretty sure that the socket extension is very, very close to compiling cleanly; we're missing that one symbol. So, at the moment, you'll need to remove socket.a for the list of objects. If you do, then you'll get a built Ruby binary:
$ ls -l ruby.exe
-rwxr-xr-x 1 megatron users 2805351 2008-02-23 15:40 ruby.exe

You can now do a make install and copy the three resultant folders (bin, lib and man) to your Pocket PC. Strip the binaries if you wish.
You will also need to copy the three libraries (cegcc.dll, cegccthrd.dll, libstdc++.dll) from /exportATA/development/wince/cegcc/arm-wince-cegcc/lib/device to the \windows directory of your mobile device. Don't forget this step as nothing you compile with CEGCC will work without these libraries!

Does it work?
Let's find out...


And how about 'irb'?...


Do the standard extensions work?

I guess that's a yes then! :-)

However...

Issues?
Although the main Ruby interpreter now seems to work (mostly) without issue, there are still serious problems remaining that are particular to the Windows CE environment. The most serious of these is the lack of relative directory support; this has the effect of forcing all of your 'require' statements to be fully qualified paths. This means that Rubygems won't install, severely reducing the usefulness of Ruby on these devices:
See how I have to give the full path to the setup.rb, and because 'rubygems' is not in the default location of \ruby\lib\ruby\1.8 it is therefore not found:


Going back to our earlier problems with ext/socket, we can see now that anything that depends on it is broken..



So far I have managed to get part way through the install of Rubygems, by performing the following:
copy rubygems-1.0.1/lib/* to /ruby/lib/ruby/1.8
edit rubygems-1.0.1/setup.rb to use full pathnames whereever os.chdir is called


This then seems to get most of the way through building and installing rubygems, but it fails on our old friend 'require socket'. If we could get that issue sorted, then I think we could take this quite a bit further (I'd love to see Rails and sqlite running!). As it is, it's frustratingly short of being really productive.

Gems - 24th Feb, 2008
With the latest release now having a 'working' socket extension Gems can now install and run! Yay!



More Extensions - 24th Feb, 2008
Quite a few of the Ruby extensions now build and work...


Have a play with the latest download (240308) and give it a try.
A working patch for a plain Ruby source tree is coming shortly!

Sockets are working! - 24th Feb, 2008
The functions I patched in ext/socket/ and the simple socket connection tests from ruby-doc.org actually run!


This bodes extremely well for further, more complicated developments.... watch this space!

Regression Testing - 1st March, 2008
I've been doing a bit of work during the evenings this week - first the bad news; I just can't get Gem to work at all...
The good bit about gem is that is does actually connect to rubyforge and download the compressed gem metadata (Marshal.x.y.Z) - this is confirmed by my web proxy showing the request from the PDA (both emulated and physical versions).
However the bad bit is not promising at all; on download Ruby works away for a few seconds and then blows up with a memory allocation error... I don't think there's a way around this. I'm also having trouble installing gems locally. Looks like we're going to have to rely on building from setup.rb's whenever we install a new package with Ruby on Arm-Wince-CEGCC.
I have a feeling this memory allocation issue is going to bite me again. On a related note, a colleague at work is playing around with PythonCE + Django on the same hardware as me, and despite the ready built PythonCE binary, he's also seeing very, very tight tolerances in the amount of free memory. I wish Windows CE itself didn't eat 20+Mb of the standard 64Mb :-(

I almost got a working Rails installation up and running - it only needs a few relative path changes to work from a storage card location (I'm working on the assumption that the ~10mb Ruby base installation would go in the built-in flash of a PDA, but a Rails instance, being larger at ~20-30mb would likely sit on a CF or SD card).
These changes are relatively minor, and I'll post a patch in the files section for anyone who wants to try it - there are errors preventing me from going any further at the moment. So I've decided to go back and see if I can get the whole regression test suite from the Ruby source code working.. when cross compiling those tests can't be run - so we need to run them from Windows CE instead.. again the relative path problem strikes!
It's not looking too bad in terms of overall compatability for the Ruby Arm-Wince-CEGCC platform; a lot of the tests run without error. But I think some of those that do error out could well be causing the Gem and Rails problems I'm seeing. I'll be creating an 'overlay' archive that you can unzip over your Windows CE Ruby install and run the regression tests.

I'm also looking at building a shared libary version of Ruby in order to reduce memory use; the binary is a bit fat right now. So far I've managed to build a .dll version of zlib, and I have made some progress with OpenSSL.. that should help. I'll also listen to any suggestions for which extensions to build and which to leave out - socket, thread, stringio, zlib and openssl are looking like the main ones to retain for now.

Shared Libraries & Ext modules - 2nd March, 2008
I haven't been able to get the Ruby configure or makefiles to do it automatically for me, but it does look like it is possible to build the extensions and even libruby as dynamic DLL's, so the only whatever is 'require'-ed will be loaded. This should help greatly in reduced memory use.
Anyway, if you configure the source code as below:

CC=arm-wince-cegcc-gcc \
CPP=arm-wince-cegcc-cpp \
CFLAGS="-Os -g" \
LIBS="-lcegcc.dll" \
LDFLAGS="-L/exportATA/development/wince/cegcc/arm-wince-cegcc/lib" \
./configure \
--disable-ipv6 \
--host=arm-wince-cegcc \
--enable-shared \
--prefix=/ruby \
-C

 .. and also edit your ext/Setup to choose which modules you want, run make as normal.
Now, you'll have to edit each ext/MODULE/Makefile to remove the -fPIC flag and change the LDSHARED value from:
LDSHARED = "ld"

 to:
LDSHARED = arm-wince-cegcc-gcc --shared

This will cause the arm-wince-cegcc-gcc compiler to enable several additional macros and produce a Windows CE compatible DLL. You will need to do this for each ext module you are using - sorry I haven't figured out how to get configure to produce valid ext Makefiles by itself yet.
You can check you've got a valid dll by changing to your main Ruby source direct and then to ".ext/arm-cegcc/", run "file *.so" and you'll see something like:
/ruby-1.8.6-p111/.ext/arm-cegcc $ file *.so
bigdecimal.so: MS-DOS executable PE for MS Windows (DLL) 32-bit
digest.so: MS-DOS executable PE for MS Windows (DLL) 32-bit
enumerator.so: MS-DOS executable PE for MS Windows 32-bit
fcntl.so: MS-DOS executable PE for MS Windows 32-bit
nkf.so: MS-DOS executable PE for MS Windows 32-bit
sdbm.so: MS-DOS executable PE for MS Windows 32-bit
syck.so: MS-DOS executable PE for MS Windows 32-bit
thread.so: MS-DOS executable PE for MS Windows (DLL) 32-bit

 You can see in the above example the difference between a normal shared object and the DLL version.

Links
http://www.cygwin.com - Cygwin, Unix-like environment and tools for Windows.
http://cegcc.sourceforge.net - CEGCC Project, ARM+WinCE cross development toolchain.
http://www.ruby-lang.org - Homepage and downloads for the Ruby programming language.
http://www.ruby-forum.org - Discussion and news forums for Ruby.

Download Shell script which unpacks a clean Ruby 1.8.6 source tree and applies my WinCE/ARM patch
Download My last patch against a clean Ruby 1.8.6-p114 source tree.
Download Script to remove any references to -fPIC after configuring the Ruby 1.8.6-p114 source.
Download Attempt to build shared binaries from the patched Ruby 1.8.6-p114 source.
Download Attempt to build static binaries from the patched Ruby 1.8.6-p114 source.
Cross compilation command aliases
24th Feb 2008 - Ruby 1.8.6-p111 for WinCE/ARM -O3 Optimised binaries for Windows CE/ARM - includes complete working Gem install.
PocketConsole, DLL, Registry tool and instructions for setting up a console on Windows CE
Rubygems-1.0.1 initial setup.rb file - for those who want to try to get it working.