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(emacs)MS-DOS Printing

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Printing and MS-DOS
===================

   Printing commands, such as `lpr-buffer' (Note: Hardcopy) and
`ps-print-buffer' (Note: PostScript) can work in MS-DOS and
MS-Windows by sending the output to one of the printer ports, if a
Posix-style `lpr' program is unavailable.  The same Emacs variables
control printing on all systems (Note: Hardcopy), but in some cases
they have different default values on MS-DOS and MS-Windows.

   If you want to use your local printer, printing on it in the usual
DOS manner, then set the Lisp variable `lpr-command' to `""' (its
default value) and `printer-name' to the name of the printer port--for
example, `"PRN"', the usual local printer port (that's the default), or
`"LPT2"', or `"COM1"' for a serial printer.  You can also set
`printer-name' to a file name, in which case "printed" output is
actually appended to that file.  If you set `printer-name' to `"NUL"',
printed output is silently discarded (sent to the system null device).

   On MS-Windows, when the Windows network software is installed, you
can also use a printer shared by another machine by setting
`printer-name' to the UNC share name for that printer-for example,
`"//joes_pc/hp4si"'.  (It doesn't matter whether you use forward
slashes or backslashes here.)  To find out the names of shared printers,
run the command `net view' at a DOS command prompt to obtain a list of
servers, and `net view SERVER-NAME' to see the names of printers (and
directories) shared by that server.  Alternatively, click the `Network
Neighborhood' icon on your desktop, and look for machines which share
their printers via the network.

   If the printer doesn't appear in the output of `net view', or if
setting `printer-name' to the UNC share name doesn't produce a hardcopy
on that printer, you can use the `net use' command to connect a local
print port such as `"LPT2"' to the networked printer.  For example,
typing `net use LPT2: \\joes_pc\hp4si'(1) causes Windows to "capture"
the LPT2 port and redirect the printed material to the printer
connected to the machine `joes_pc'.  After this command, setting
`printer-name' to `"LPT2"' should produce the hardcopy on the networked
printer.

   With some varieties of Windows network software, you can instruct
Windows to capture a specific printer port such as `"LPT2"', and
redirect it to a networked printer via the `Control Panel->Printers'
applet instead of `net use'.

   Some printers expect DOS codepage encoding of non-ASCII text, even
though they are connected to a Windows machine which uses a different
encoding for the same locale.  For example, in the Latin-1 locale, DOS
uses codepage 850 whereas Windows uses codepage 1252.  Note: MS-DOS and
MULE.  When you print to such printers from Windows, you can use the
`C-x RET c' (`universal-coding-system-argument') command before `M-x
lpr-buffer'; Emacs will then convert the text to the DOS codepage that
you specify.  For example, `C-x RET c cp850-dos RET M-x lpr-region RET'
will print the region while converting it to the codepage 850 encoding.
You may need to create the `cpNNN' coding system with `M-x
codepage-setup'.

   If you set `printer-name' to a file name, it's best to use an
absolute file name.  Emacs changes the working directory according to
the default directory of the current buffer, so if the file name in
`printer-name' is relative, you will end up with several such files,
each one in the directory of the buffer from which the printing was
done.

   The commands `print-buffer' and `print-region' call the `pr'
program, or use special switches to the `lpr' program, to produce
headers on each printed page.  MS-DOS and MS-Windows don't normally
have these programs, so by default, the variable `lpr-headers-switches'
is set so that the requests to print page headers are silently ignored.
Thus, `print-buffer' and `print-region' produce the same output as
`lpr-buffer' and `lpr-region', respectively.  If you do have a suitable
`pr' program (for example, from GNU Textutils), set
`lpr-headers-switches' to `nil'; Emacs will then call `pr' to produce
the page headers, and print the resulting output as specified by
`printer-name'.

   Finally, if you do have an `lpr' work-alike, you can set the
variable `lpr-command' to `"lpr"'.  Then Emacs will use `lpr' for
printing, as on other systems.  (If the name of the program isn't
`lpr', set `lpr-command' to specify where to find it.)  The variable
`lpr-switches' has its standard meaning when `lpr-command' is not `""'.
If the variable `printer-name' has a string value, it is used as the
value for the `-P' option to `lpr', as on Unix.

   A parallel set of variables, `ps-lpr-command', `ps-lpr-switches',
and `ps-printer-name' (Note: PostScript Variables), defines how
PostScript files should be printed.  These variables are used in the
same way as the corresponding variables described above for
non-PostScript printing.  Thus, the value of `ps-printer-name' is used
as the name of the device (or file) to which PostScript output is sent,
just as `printer-name' is used for non-PostScript printing.  (There are
two distinct sets of variables in case you have two printers attached
to two different ports, and only one of them is a PostScript printer.)

   The default value of the variable `ps-lpr-command' is `""', which
causes PostScript output to be sent to the printer port specified by
`ps-printer-name', but `ps-lpr-command' can also be set to the name of
a program which will accept PostScript files.  Thus, if you have a
non-PostScript printer, you can set this variable to the name of a
PostScript interpreter program (such as Ghostscript).  Any switches
that need to be passed to the interpreter program are specified using
`ps-lpr-switches'.  (If the value of `ps-printer-name' is a string, it
will be added to the list of switches as the value for the `-P' option.
This is probably only useful if you are using `lpr', so when using an
interpreter typically you would set `ps-printer-name' to something
other than a string so it is ignored.)

   For example, to use Ghostscript for printing on an Epson printer
connected to the `LPT2' port, put this in your `_emacs' file:

     (setq ps-printer-name t)  ; Ghostscript doesn't understand -P
     (setq ps-lpr-command "c:/gs/gs386")
     (setq ps-lpr-switches '("-q" "-dNOPAUSE"
     			"-sDEVICE=epson"
     			"-r240x72"
     			"-sOutputFile=LPT2"
     			"-Ic:/gs"))

(This assumes that Ghostscript is installed in the `"c:/gs"' directory.)

   For backwards compatibility, the value of `dos-printer'
(`dos-ps-printer'), if it has a value, overrides the value of
`printer-name' (`ps-printer-name'), on MS-DOS and MS-Windows only.

   ---------- Footnotes ----------

   (1) Note that the `net use' command requires the UNC share name to be
typed with the Windows-style backslashes, while the value of
`printer-name' can be set with either forward- or backslashes.