Modifying Printer Interface Sources

The HPsupplied local printer interfaces are implemented in program lpout, the source files to which are provided with the LP spooler. See the instructions contained in comments in the files for help in making modifications. Some files that you may wish to modify or use as the basis of a new printer interface are:

lpout_if.ftn

Interface support routines, including those that recognize local interface

lpout_m.mac

names and call the appropriate handler routines.

lpout_rtestd.ftn

The nonPCL portions of the rtestd interface.

pcl.ftn

PCL printer support for the pcl and hpnp_pcl models. Changes

 

made to this file will be reflected in the operation of both models if both

 

the lpout and rlpout programs are reloaded.

lpout_passthru.ftn

The passthru interface.

Look for the comment •* POSSIBLE USER MODIFICATION" for suggestions on customizing.

Programming Considerations

The lpout program suspends in •operator suspend" state just after starting if the local printer name begins with the string •debug". This allows the program to be adopted with Debug/1000 before continuing.

When an activelyprinting request is either cancelled via the cancel program or aborted via the disable or lpshut programs, the printer interface program scheduled by lpsched is OF'ed. Any programs scheduled in turn by the interface program are not OF'ed. Thus, any activity performed by programs scheduled by interface programs does not halt when an active request is terminated. For this reason, the HPsupplied interface programs do not schedule other programs that are expected to be OF'ed if the interface program is OF'ed.

262 LP Spool System