path: root/msdos/INSTALL

GNU Emacs Installation Guide for the DJGPP (a.k.a. MS-DOS) port

Copyright (C) 1992, 1994, 1996-1997, 2000-2011  Free Software Foundation, Inc.
See the end of the file for license conditions.

The DJGPP port of GNU Emacs builds and runs on plain DOS and also on
all versions of MS-Windows from version 3.X on, including Windows XP,
Vista, and Windows 7 (however, see below for issues with Windows Vista
and 7).

To build and install the DJGPP port, you need to have the DJGPP ports
of GCC (the GNU C compiler), GNU Make, rm, mv, and sed.  See the
remarks in CONFIG.BAT for more information about locations and
versions.  The Emacs FAQ (see info/efaq) includes pointers to Internet
sites where you can find the necessary utilities; search for "MS-DOS".
The configuration step (see below) will test for these utilities and
will refuse to continue if any of them isn't found.

Bootstrapping Emacs or recompiling Lisp files in the `lisp'
subdirectory using the various targets in the lisp/Makefile file
requires additional utilities: `find' (from Findutils), GNU `echo' and
`test' (from Sh-utils or Coreutils), `ls' and `chmod' (from Fileutils
or Coreutils), `grep' (from Grep), and a port of Bash.  However, you
should not normally need to run lisp/Makefile, as all the Lisp files
are distributed in byte-compiled form as well.  As for bootstrapping
itself, you will only need that if you check-out development sources
from the Emacs source repository.

If you are building the DJGPP version of Emacs on a DOS-like system
which supports long file names (e.g. Windows 9X or Windows XP), you
need to make sure that long file names are handled consistently both
when you unpack the distribution and compile it.  With DJGPP v2.0 or
later, long file names support is by default, so you need to unpack
Emacs distribution in a way that doesn't truncate the original long
filenames to the DOS 8.3 namespace; the easiest way to do this is to
use djtar program which comes with DJGPP, since it will behave
consistently with the rest of DJGPP tools.  Alternatively, you can
build Emacs with LFN=n, if some of your tools don't support long file
names: just ensure that LFN is set to `n' during both unpacking and
compiling.

(By the time you read this, you have already unpacked the Emacs
distribution, but if the explanations above imply that you should have
done it differently, it's safer to delete the directory tree created
by the unpacking program and unpack Emacs again, than to risk running
into strange problems during the build process.)

It is important to understand that the runtime support of long file
names by the Emacs binary is NOT affected by the LFN setting during
compilation; Emacs compiled with DJGPP v2.0 or later will always
support long file names on Windows no matter what was the setting
of LFN at compile time.  However, if you compiled with LFN disabled
and want to enable LFN support after Emacs was already built, you need
to make sure that the support files in the lisp, etc and info
directories are called by their original long names as found in the
distribution.  You can do this either by renaming the files manually,
or by extracting them from the original distribution archive with
djtar after you set LFN=y in the environment.

To unpack Emacs with djtar, type this command:

    djtar -x emacs.tgz

(This assumes that the Emacs distribution is called `emacs.tgz' on
your system.)

When unpacking Emacs is done, a directory called `emacs-XX.YY' will be
created, where XX.YY is the Emacs version.

On plain DOS, unpacking can complain about several directories and
files in the `nextstep' subdirectory of the `emacs-XX.YY' top-level
directory.  This is because the names of these files overflow the
67-character limit on the file-name length imposed by DOS filesystems.
When prompted by `djtar' for a different name for these files, just
press [Enter] to skip them: they are not needed for the DJGPP build.

If you want to print international characters, install the intlfonts
distribution.  For this, create a directory called `fonts' under the
`emacs-XX.YY' top-level directory created by unpacking emacs.tgz,
chdir into the directory `emacs-XX.YY/fonts', and type this:

    djtar -x intlfonts.tgz

To build and install Emacs, chdir to the `emacs-XX.YY' directory and
type these commands:

    config msdos
    make install

Running "config msdos" checks for several programs that are required
to configure and build Emacs; if one of those programs is not found,
CONFIG.BAT stops and prints an error message.  If you have DJGPP
version 2.0 or 2.01, it will complain about a program called
DJECHO.EXE.  These old versions of DJGPP shipped that program under
the name ECHO.EXE, so you can simply copy ECHO.EXE to DJECHO.EXE and
rerun CONFIG.BAT.  If you have neither ECHO.EXE nor DJECHO.EXE, you
should be able to find them in your djdevNNN.zip archive (where NNN is
the DJGPP version number).

On Windows NT and Windows 2000/XP/Vista/7, running "config msdos"
might print an error message like "VDM has been already loaded".  This
is because those systems have a program called `redir.exe' which is
incompatible with a program by the same name supplied with DJGPP,
which is used by config.bat.  To resolve this, move the DJGPP's `bin'
subdirectory to the front of your PATH environment variable.

Windows Vista/7 has several bugs in its DPMI server related to memory
allocation: it fails DPMI resize memory block function, and it
arbitrarily limits the default amount of DPMI memory to 32MB.  To work
around these bugs, first configure Emacs to use the `malloc' function
from the DJGPP library.  To this end, run CONFIG.BAT with the
"--with-system-malloc" option:

    config --with-system-malloc msdos
    make install

In addition, for Windows Vista you'll need to install Service Pack 1
(SP1) or later and enlarge its DPMI memory limit by setting the value
of this Registry key:

  HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Wow\DpmiLimit

Create this key if it does not exist.  The value is a DWORD; setting
it to 536870912 should let Emacs use up to 512MB of memory.

If you have other problems, either building Emacs or running the
produced binary, look in the file etc/PROBLEMS for some known problems
related to the DJGPP port (search for "MS-DOS").

To install the international fonts, chdir to the intlfonts-X.Y
directory created when you unpacked the intlfonts distribution (X.Y is
the version number of the fonts' distribution), and type the following
command:

    make bdf INSTALLDIR=..

After Make finishes, you may remove the directory intlfonts-X.Y; the
fonts are installed into the fonts/bdf subdirectory of the top-level
Emacs directory, and that is where Emacs will look for them by
default.

Building Emacs creates executable files in the src and lib-src
directories.  Installing the DJGPP port of Emacs moves these
executables to a sibling directory called bin.  For example, if you
build in directory C:/emacs, installing moves the executables from
C:/emacs/src and C:/emacs/lib-src to the directory C:/emacs/bin, so
you can then delete the subdirectories C:/emacs/src and
C:/emacs/lib-src if you wish.  The only subdirectories you need to
keep are bin, lisp, etc and info.  (If you installed intlfonts, keep
the fonts directory and all its subdirectories as well.)  The bin
subdirectory should be added to your PATH.  The msdos subdirectory
includes a PIF and an icon file for Emacs which you might find useful
if you run Emacs under MS Windows.

Emacs on MSDOS finds the lisp, etc and info directories by looking in
../lisp, ../etc and ../info, starting from the directory where the
Emacs executable was run from.  You can override this by setting the
environment variables EMACSDATA (for the location of `etc' directory),
EMACSLOADPATH (for the location of `lisp' directory) and INFOPATH (for
the location of the `info' directory).

Emacs features which require asynchronous subprocesses that depend on
multitasking do not work in the DJGPP port.  Synchronous subprocesses
do work, so features such as compilation, grep, and Ispell run
synchronously, unlike on other platforms.

Version 2.0 of djgpp has two bugs that affect Emacs.  We've included
corrected versions of two files from djgpp in the msdos subdirectory:
is_exec.c and sigaction.c.  To work around the bugs, compile these
files and link them into temacs.  Djgpp versions 2.01 and later have
these bugs fixed, so upgrade if you can before building Emacs.


This file is part of GNU Emacs.

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