Very Computer

Howdy,

I've an HP LaserJet 5MP (Postscript) attached to my linux
box's parallel port --- sometimes I can print multiple files,
other times I cannot.  For example

lpr tst.ps
lpr a.c

will _not_ print "a.c" even though it gets spooled ok.
If, however, I wait until "tst.ps" has printed, then I
can print a.c _no problem_.  I suspect that it has
something to do with the way the printer's internal
memory is caching things (2MB internal).  Possibly I
need to send some printer control codes at the end of
each job, perhaps using an output filter?

any suggestions would be greatly appreciated,
thanks,

        Eric Welton

    #define RESET       "\033E"


    #define CTRLD       "\004"
    #define END_PJL     "\033%-12345X"
    ...
    void PrintPostScriptFile()
    {
        /* Choose language */
        fprintf(stdout,"%s%s%s",RESET,START_PJL,POSTSCRIPT);
        /* Transmit file transparently */
        putc(c0,stdout);
        for (bytes = 1; c != EOF; bytes++) { putc(c,stdout); c = getc(stdin); }
        /* Add newline, Ctrl-D, ... */
        fprintf(stdout,"\n%s",CTRLD);
        /* ... and reset printer at end */
        fprintf(stdout,"%s%s",END_PJL,RESET);
        /* Log results */
        syslog(LOG_DEBUG,"%s, PostScript file, %ld bytes",userinfo,bytes);
    }

I think just the control-D may be sufficient to terminate the printer's
PostScript interpreter and allow it to go back to auto-detecting the
text file.  Without it I suspect there's a time-out in the printer after
a PostScript file before text will be properly printed.
--

Quote:>Howdy,
>I've an HP LaserJet 5MP (Postscript) attached to my linux
>box's parallel port --- sometimes I can print multiple files,
>other times I cannot.  For example
>lpr tst.ps
>lpr a.c
>will _not_ print "a.c" even though it gets spooled ok.
>If, however, I wait until "tst.ps" has printed, then I
>can print a.c _no problem_.  I suspect that it has
>something to do with the way the printer's internal
>memory is caching things (2MB internal).  Possibly I
>need to send some printer control codes at the end of
>each job, perhaps using an output filter?

Rob
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