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gtroff
OutputThis section describes the intermediate output format of GNU
troff
. This output is produced by a run of gtroff
before
it is fed into a device postprocessor program.
As groff
is a wrapper program around gtroff
that
automatically calls a postprocessor, this output does not show up
normally. This is why it is called intermediate. groff
provides the option -Z to inhibit postprocessing, such that the
produced intermediate output is sent to standard output just like
calling gtroff
manually.
Here, the term troff output describes what is output by
gtroff
, while intermediate output refers to the language
that is accepted by the parser that prepares this output for the
postprocessors. This parser is smarter on whitespace and implements
obsolete elements for compatibility, otherwise both formats are the
same.29
The main purpose of the intermediate output concept is to facilitate the
development of postprocessors by providing a common programming
interface for all devices. It has a language of its own that is
completely different from the gtroff
language. While the
gtroff
language is a high-level programming language for text
processing, the intermediate output language is a kind of low-level
assembler language by specifying all positions on the page for writing
and drawing.
The intermediate output produced by gtroff
is fairly readable,
while output from AT&T troff
is rather hard to
understand because of strange habits that are still supported, but not
used any longer by gtroff
.
• Language Concepts: | ||
• Command Reference: | ||
• Intermediate Output Examples: | ||
• Output Language Compatibility: |
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