Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!decwrl!ucbvax!agate!violet.berkeley.edu!izumi
From: izumi@violet.berkeley.edu (Izumi Ohzawa)
Newsgroups: comp.lang.postscript
Subject: Re: Debugging Postscript
Keywords: Errors, Debugging.
Message-ID: <22037@agate.BERKELEY.EDU>
Date: 25 Mar 89 08:08:20 GMT
References: <11401@pasteur.Berkeley.EDU>
Sender: usenet@agate.BERKELEY.EDU
Distribution: usa
Organization: University of California, Berkeley
Lines: 34

In article <11401@pasteur.Berkeley.EDU> gar@cory.Berkeley.EDU (Gary D. Wong) writes:
> Can anyone suggest a good method of finding errors in 
>postscript files?  It seems to me that the only way to know if an error
>exists is if the file does not print. Besides using the interactive mode,
>does PS have any type of feedback that might lead to the soruce of the error?
>

If you are running the PostScript printer via its serial port, and
can locate a spare CRT terminal,  directly connect the terminal's
serial input to the printer's 'stdout' pin.  I forgot which
pin, but it's either 2 or 3.  You also need the pin-7 for the 
ground.

With this, you can see all error and status messages that the
printer generates.  Frankly, I don't know why any of the PostScript
printer manufacturers can't put a 5 line LCD display which
show the last 5 lines of 'stdout' output right on the printer.

In any case, you can use this display for debugging purposes
more actively as if you sprinkle "printf()'s" in debugging
C programs.  This can be done by including,

 ...... your PostScript lines....
 ( Before doing AAA.\n) print flush

 ... AAA ...
 ( After doing AAA.\n) print flush

 ....

You get the idea.  I can't do without it now.

Izumi Ohzawa
izumi@violet.berkeley.edu