source: vendor/perl/5.8.8/README.dos@ 3210

If you read this file _as_is_, just ignore the funny characters you
see. It is written in the POD format (see perlpod manpage) which is
specially designed to be readable as is.

=head1 NAME

perldos - Perl under DOS, W31, W95.

=head1 SYNOPSIS

These are instructions for building Perl under DOS (or w??), using
DJGPP v2.03 or later.  Under w95 long filenames are supported.

=head1 DESCRIPTION

Before you start, you should glance through the README file
found in the top-level directory where the Perl distribution
was extracted.  Make sure you read and understand the terms under
which this software is being distributed.

This port currently supports MakeMaker (the set of modules that
is used to build extensions to perl).  Therefore, you should be
able to build and install most extensions found in the CPAN sites.

Detailed instructions on how to build and install perl extension
modules, including XS-type modules, is included.  See 'BUILDING AND
INSTALLING MODULES'.

=head2 Prerequisites for Compiling Perl on DOS

=over 4

=item DJGPP

DJGPP is a port of GNU C/C++ compiler and development tools to 32-bit,
protected-mode environment on Intel 32-bit CPUs running MS-DOS and compatible
operating systems, by DJ Delorie <[email protected]> and friends.

For more details (FAQ), check out the home of DJGPP at:

        http://www.delorie.com/djgpp/

If you have questions about DJGPP, try posting to the DJGPP newsgroup:
comp.os.msdos.djgpp, or use the email gateway [email protected].

You can find the full DJGPP distribution on any SimTel.Net mirror all over
the world. Like:

        ftp://ftp.simtel.net/pub/simtelnet/gnu/djgpp/v2*

You need the following files to build perl (or add new modules):

        v2/djdev203.zip
        v2gnu/bnu2112b.zip
        v2gnu/gcc2953b.zip
        v2gnu/bsh204b.zip
        v2gnu/mak3791b.zip
        v2gnu/fil40b.zip
        v2gnu/sed3028b.zip
        v2gnu/txt20b.zip
        v2gnu/dif272b.zip
        v2gnu/grep24b.zip
        v2gnu/shl20jb.zip
        v2gnu/gwk306b.zip
        v2misc/csdpmi5b.zip

or possibly any newer version.

=item Pthreads

Thread support is not tested in this version of the djgpp perl.

=back

=head2 Shortcomings of Perl under DOS

Perl under DOS lacks some features of perl under UNIX because of
deficiencies in the UNIX-emulation, most notably:

=over 4

=item *

fork() and pipe()

=item *

some features of the UNIX filesystem regarding link count and file dates

=item *

in-place operation is a little bit broken with short filenames

=item *

sockets

=back

=head2 Building Perl on DOS

=over 4

=item *

Unpack the source package F<perl5.8*.tar.gz> with djtarx. If you want
to use long file names under w95 and also to get Perl to pass all its
tests, don't forget to use

        set LFN=y
        set FNCASE=y

before unpacking the archive.

=item *

Create a "symlink" or copy your bash.exe to sh.exe in your C<($DJDIR)/bin>
directory.

        ln -s bash.exe sh.exe

[If you have the recommended version of bash for DJGPP, this is already
done for you.]

And make the C<SHELL> environment variable point to this F<sh.exe>:

        set SHELL=c:/djgpp/bin/sh.exe (use full path name!)

You can do this in F<djgpp.env> too. Add this line BEFORE any section
definition:

        +SHELL=%DJDIR%/bin/sh.exe

=item *

If you have F<split.exe> and F<gsplit.exe> in your path, then rename 
F<split.exe> to F<djsplit.exe>, and F<gsplit.exe> to F<split.exe>.
Copy or link F<gecho.exe> to F<echo.exe> if you don't have F<echo.exe>.
Copy or link F<gawk.exe> to F<awk.exe> if you don't have F<awk.exe>.

[If you have the recommended versions of djdev, shell utilities and
gawk, all these are already done for you, and you will not need to do
anything.]

=item *

Chdir to the djgpp subdirectory of perl toplevel and type the following
commands:

        set FNCASE=y
        configure.bat

This will do some preprocessing then run the Configure script for you.
The Configure script is interactive, but in most cases you just need to
press ENTER.  The "set" command ensures that DJGPP preserves the letter
case of file names when reading directories.  If you already issued this
set command when unpacking the archive, and you are in the same DOS
session as when you unpacked the archive, you don't have to issue the
set command again.  This command is necessary *before* you start to 
(re)configure or (re)build perl in order to ensure both that perl builds 
correctly and that building XS-type modules can succeed.  See the DJGPP 
info entry for "_preserve_fncase" for more information:

        info libc alphabetical _preserve_fncase

If the script says that your package is incomplete, and asks whether
to continue, just answer with Y (this can only happen if you don't use
long filenames or forget to issue "set FNCASE=y" first).

When Configure asks about the extensions, I suggest IO and Fcntl,
and if you want database handling then SDBM_File or GDBM_File
(you need to install gdbm for this one). If you want to use the
POSIX extension (this is the default), make sure that the stack
size of your F<cc1.exe> is at least 512kbyte (you can check this
with: C<stubedit cc1.exe>).

You can use the Configure script in non-interactive mode too.
When I built my F<perl.exe>, I used something like this:

        configure.bat -des

You can find more info about Configure's command line switches in
the F<INSTALL> file.

When the script ends, and you want to change some values in the
generated F<config.sh> file, then run

        sh Configure -S

after you made your modifications.

IMPORTANT: if you use this C<-S> switch, be sure to delete the CONFIG
environment variable before running the script: