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5.30 Postprocessor Access

There are two escapes which give information directly to the postprocessor. This is particularly useful for embedding PostScript into the final document.

— Request: .device xxx
— Escape: \X'xxx'

Embeds its argument into the gtroff output preceded with ‘x X.

The escapes \&, \), \%, and \: are ignored within \X, ‘ and \~ are converted to single space characters. All other escapes (except \\ which produces a backslash) cause an error.

Contrary to \X, the device request simply processes its argument in copy mode (see Copy-in Mode).

If the ‘use_charnames_in_special’ keyword is set in the DESC file, special characters no longer cause an error; they are simply output verbatim. Additionally, the backslash is represented as \\.

use_charnames_in_special’ is currently used by grohtml only.

— Request: .devicem xx
— Escape: \Yn
— Escape: \Y(nm
— Escape: \Y[name]

This is approximately equivalent to ‘\X'\*[name]'’ (one-character name n, two-character name nm). However, the contents of the string or macro name are not interpreted; also it is permitted for name to have been defined as a macro and thus contain newlines (it is not permitted for the argument to \X to contain newlines). The inclusion of newlines requires an extension to the UNIX troff output format, and confuses drivers that do not know about this extension (see Device Control Commands).

See Output Devices.