File: groff.info,  Node: Argument Units,  Next: Document Parts,  Prev: Separation,  Up: Language Concepts

6.1.1.2 Argument Units
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Some commands take integer arguments that are assumed to represent
values in a measurement unit, but the letter for the corresponding
scaling unit is not written with the output command arguments.  Most
commands assume the scaling unit 'u', the basic unit of the device, some
use 'z', the scaled point unit of the device, while others, such as the
color commands, expect plain integers.

   Single characters can have the eighth bit set, as can the names of
fonts and special characters.  The names of characters and fonts can be
of arbitrary length.  A character that is to be printed is always in the
current font.

   A string argument is always terminated by the next whitespace
character (space, tab, or newline); an embedded '#' character is
regarded as part of the argument, not as the beginning of a comment
command.  An integer argument is already terminated by the next
non-digit character, which then is regarded as the first character of
the next argument or command.