troff, C/A/T and dvi ?

[Doug Gwyn]

In article <STEF.90Jul12181552 at zweig.sun> stef at zweig.sun (Stephane Payrard) writes:
>Where I can find a complete definition of the C/A/T format?

Presumably you would have to get the C/A/T programmer's manual from Wang.
Somebody (possibly Henry Spencer) once posted a UNIX manual entry that
described the format sufficiently for use in designing otroff postprocessors.

>What is the relationship between the C/A/T format and the dvi format.

There isn't any.  There do exist programs that translate from one to the
other.

>Do every possible troff (ATT troff, Berkeley troff...) called by "troff
>-t ..." line command emit always C/A/T format (if yes, read instead
>"always the same C/A/T format")?

No, in fact modern troff produces a device-independent text format that
requires postprocessing for whatever device you happen to want the image
displayed on.  Old versions of troff, known as otroff to those using
modern troff, either directly open /dev/cat or else, with the -t option,
send C/A/T codes to the standard output.  New troff (sometimes known as
ditroff to those using old troff) always sends to standard output; -t is
not needed.

If you need to adapt troff to some new device, I highly recommend starting
with modern troff as found in the Documenter's WorkBench package (also
sold with enhancements by various third-party VARs).