Specifications

4-152
Guide to Printers and Printing
This frequently removes all the printer control problems that existed, but adds one new one.
When the formatter filter operates in passthru mode, the mapping of linefeeds to carriage
returns and linefeeds is disabled. The forms still do not print correctly.
Suppose that the application does not allow the insertion of carriage returns into the data
stream, you can fix this problem with a simple filter, as follows:
#include <stdio.h>
main(int argc, char **argv)
{
int ch ;
while (EOF != (ch = fgetc(stdin)))
{
switch (ch)
{
case 10: fputc(ch,stdout) ;
fputc(0x0D,stdout) ;
break ;
default: fputc(ch,stdout) ;
break ;
}
}
}
Compile your program and name it cr_mapper. and install it in an accessible location, such
as /usr/lib/lpd. Assign it ownership of root.printq and permissions 555.
Assuming you have an ASCII queue named asc on an IBM 4029 LaserPrinter, you can use
lsvirprt to select the asc queue and then format the f1 filter attribute. You should see
something like the following:
User defined filter 1
f1 =
As the f1 attribute has a null default value, the definition is sparse.
Edit the f1 attribute so its definition appears as follows:
User defined filter 1
f1 =
’/usr/lib/lpd/cr_mapper’
When you save the new definition of f1, you can again format it with lsvirprt; you should
see something like the following:
User defined filter 1
f1 = /usr/lib/lpd/cr_mapper
’/usr/lib/lpd/cr_mapper’
The f1 filter can now be used from the command line by using commands such as:
qprt –Pasc –f1 filename
enq –Pasc –o –f –o 1 filename
If the _d attribute was not set to p, the –dp flag and argument would have to be added to the
commands.
qprt –Pasc –dp –f1 filename
enq –Pasc –o –d –o p –o –f –o 1 filename
The cr_mapper program reads characters from stdin and writes them to stdout. Whenever
it reads and writes a linefeed (a hex A, or decimal 10), it writes out a carriage return (a hex
D).