Conference hydra::amiga_v1

4528.0. "Any printer driver authors out there?" by AISG::LANDINGHAM (Guy M., DLB5-3/E5, 291-9268) Wed Feb 20 1991 15:07

I am experimenting with writing a printer driver and was wondering if anyone
else who has done so can answer a couple of questions...

Question 1:
In data.c, each printer control sequence is specified as a constant string.  For
instance, if my printer uses, say, ESC@ to do a reset, then in data.c:

	"\027@",	/* aRIS (or whatever) */

My question is: how does this work if the control sequence takes one or more
parameters?  As an example, say the printer in question uses the following
sequence to set the left margin: ESCnK, where 0 < n < 81.  How is this supposed
to be specified in data.c?  Would I use "\027nK" letting the "n" serve as a
placeholder?  How is the parameters position in the sequence specified?  Or is
it just left out?


Question 2:
This sort of relates to question 1.  I've looked at several dospecial.c's and
they all seem to implement different printer control sequences.  Does the
printer.device use data.c for some sequences and dospecial.c for others?  What
determines which sequences need to be implemented in dospecial.c?


Thanks for any light shed on this dim subject...

I'm posting this in case anyone else is interested.

The answer is that any printer control sequence that takes parameters should be
implemented in DoSpecial.c.  Specifying "\377" as the value of a sequence in
Data.c tells the printer device that this function is either not available or
implemented in DoSpecial.c.