User`s guide

4-2
Guide to Printers and Printing
Printer Backend Overview for Programming
The AIX printer backend receives and processes print requests from a spooler, usually the
qdaemon command. The printer backend is a standard feature of the AIX system. It is
implemented by the piobe command and functions as depicted in the Printing with AIX
Operating System figure.
AIX
device
driver
Xstation
interface
LAN
Attach
interface
Socket to
server
qdaemonQueue
lp
lpr enq
qprt
Redirection
rembak
(Local)
Socket
from client
(Remote)
piobe
lpd
Printing with AIX Operating System
The printer backend supports all of the printers installed in the Object Data Manager (ODM)
Predefined database. You can customize the printer backend to assist in the administration
of the printing subsystem. For more information, see ”Printer Overview”, on page 0 . You
can also modify the printer backend to add unsupported printers and National Language
Support (NLS) code page translation tables.
Adding a printer to the printer backend involves adding a printer colon file for that printer. In
many cases, the printer colon file of a similar printer can be duplicated with little
modification. If modification of an existing printer colon file is not sufficient, you can write a
print formatter. If the modifications exceed the scope of the print formatter, you may need to
write a new printer backend.
Refer to the following sections for more information:
• ”Adding a Printer Using the Printer Colon File”, on page 4-57 provides a procedure for
duplicating a printer colon file.
• ”Printer Colon File Escape Sequences”, on page 4-14 provides information useful in
modifying a printer colon file.
• ”Understanding Backend Routines in libqb”, on page 4-33 and ”Understanding the
Interaction between qdaemon and the Backend”, on page 4-28 can assist you in writing a
new printer backend.
The procedure for translating NLS code points in the print file to code points for the printers
varies depending upon whether the code sets are single–byte or multibyte. For more
information, see:
• ”Printer Code Page Translation Tables”, on page 4-35
• ”Print Code Page Translation for Multibyte Code Sets”, on page 4-36 .
Third–party vendors may want to customize the printer backend for special purposes.