Special fonts are those that gtroff searches when it cannot find
the requested glyph in the current font. The Symbol font is usually a
special font.
gtroff provides the following two requests to add more special
fonts. See Using Symbols, for a detailed description of the glyph
searching mechanism in gtroff.
Usually, only non-TTY devices have special fonts.
Use the
specialrequest to define special fonts. Initially, this list is empty.Use the
fspecialrequest to designate special fonts only when font f is active. Initially, this list is empty.Previous calls to
specialorfspecialare overwritten; without arguments, the particular list of special fonts is set to empty. Special fonts are searched in the order they appear as arguments.All fonts which appear in a call to
specialorfspecialare loaded.See Using Symbols, for the exact search order of glyphs.