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 v2.01 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.

=head2 Prerequisites

=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 <dj@delorie.com> 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 djgpp@delorie.com.

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/djdev201.zip
        v2/bnu27b.zip
        v2gnu/gcc2721b.zip
        v2gnu/bsh1147b.zip
        v2gnu/mak3761b.zip
        v2gnu/fil316b.zip
        v2gnu/sed118b.zip
        v2gnu/txt122b.zip
        v2gnu/dif271b.zip
        v2gnu/grep21b.zip
        v2gnu/shl112b.zip
        v2gnu/gawk303b.zip
        v2misc/csdpmi4b.zip 

or any newer version.

=item Pthreads

If you want multithreading support in perl, you need a pthread library
that supports DJGPP. One of them can be found at:

        ftp://ftp.cs.fsu.edu/pub/PART/PTHREADS/pthreads.zip

But thread support is still in alpha, it may be unstable. For more information
see below.

=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

=over 4

=item *

Unpack the source package F<perl5.00?_??.tar.gz> with djtarx. If you want
to use long file names under w95, don't forget to use

        set LFN=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

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>.

=item *

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

        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.

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).

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 -Uuseposix -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:

        set CONFIG=

=item *

Now you can compile Perl. Type:

        make

=back

=head2 Testing

Type:

        make test

You should see "All tests successful" if you configured a database
manager, and 1 failed test script if not (F<lib/anydbm.t>). If you
configured POSIX you will see 1 additional failed subtest in F<lib/posix.t>.

=head2 Installation

Type:

        make install

This will copy the newly compiled perl and libraries into your DJGPP
directory structure. Perl.exe and the utilities go into C<($DJDIR)/bin>,
and the library goes under C<($DJDIR)/lib/perl5>. The pod documentation
goes under C<($DJDIR)/lib/perl5/pod>.

=head2 Threaded perl under dos-djgpp

Multithreading support is considered alpha, because some of the
tests in C<ext/Thread> still die with SIGSEGV (patches are welcome). But
if you want to give it a try, here are the necessary steps:

=over 4

=item

1. You will need a pthread library which supports djgpp. Go, and download
FSU's version from:

      ftp://ftp.cs.fsu.edu/pub/PART/PTHREADS/pthreads.zip

The latest version is 3.5, released in Feb 98.

=item 

2. Unzip the file, cd to C<threads\src> and run F<configur.bat>.

=item 

3. Add C<RAND_SWITCH> or C<MUTEX_SWITCH> or C<RR_SWITCH> to C<CFLAGS>
in the F<makefile>. Note that using these values, multithreading will
NOT be preemptive. This is necessary, since djgpp's libc is not thread safe.

=item 

4. Apply the following patch:

    *** include/pthread/signal.h~	Wed Feb  4 10:51:24 1998
    --- include/pthread/signal.h	Tue Feb 10 22:40:32 1998
    ***************
    *** 364,368 ****
    --- 364,370 ----
      
      #ifndef SA_ONSTACK
    + #ifdef  SV_ONSTACK
      #define SA_ONSTACK SV_ONSTACK
    + #endif
      #endif /* !SA_ONSTACK */

=item

5. run make (before you do this, you must make sure your C<SHELL> environment 
variable does NOT point to bash).

=item

6. Install the library and header files into your djgpp directory structure.

=item

7. Add C<-Dusethreads> to the commmand line of perl's F<configure.bat>.

=back

=head1 AUTHOR

Laszlo Molnar, F<laszlo.molnar@eth.ericsson.se>

=head1 SEE ALSO

perl(1).

=cut

