Table of Contents
The function
is a simplified version of the data base used to describe line printers.
The spooling system accesses the file every time it is used, allowing
dynamic addition and deletion of printers. Each entry in the data base
is used to describe one printer. This data base may not be substituted
for, as is possible for because it may allow accounting to be bypassed.
The default printer is normally though the environment variable may
be used to override this. Each spooling utility supports an option, to
allow explicit naming of a destination printer. Refer to the for a complete
discussion on how to setup the database for a given printer.
Refer
to for a description of the file layout. call) format) format
blocks), zero = unlimited style text files
If the local line printer driver supports indentation, the daemon
must understand how to invoke it.
The daemon creates a pipeline
of to process files for various printer types. The filters selected depend
on the flags passed to The pipeline set up is: p pr | if regular text +
pr(1)
none if regular text c cf cifplot d df DVI (tex) g gf plot(3)
n nf ditroff
f rf Fortran t tf troff v vf raster image The filter is invoked with arguments:
The flag is passed only if the flag (pass control characters
literally) is specified to The function and specify the page width and
length (from and respectively) in characters. The and parameters specify
the login name and host name of the owner of the job respectively. The
function is passed from the entry. If no is specified, is used instead,
with the distinction that is opened only once, while is opened for every
individual job. Thus, is better suited to performing accounting. The is
only given the and flags. All other filters are called as: where
and are represented in pixels, specified by the and entries respectively.
All filters take as the file, as the printer, may log either to or
using and must not ignore
Error messages generated by the line
printer programs themselves (that is, the programs) are logged by using
the facility. Messages printed on of one of the filters are sent to the
corresponding file. The filters may, of course, use themselves. Error
messages sent to the console have a carriage return and a line feed appended
to them, rather than just a line feed.
The file
format appeared in
Table of Contents