This section describes the commands for describing functions and similar entities with simple arguments:
@deffn category name arguments… ¶The @deffn command is the general definition command for
functions, interactive commands, and similar entities that may take
simple arguments. You must choose a term to describe the category of entity
being defined; for example, “Function” could be used if the entity is
a function. The @deffn command is written at the beginning of a
line and is followed on the same line by the category of entity being
described, the name of this particular entity, and its arguments, if
any. Terminate the definition with @end deffn on a line of its
own.
For example, here is a definition:
@deffn Command forward-char nchars
Move point forward @var{nchars} characters.
@end deffn
This shows a rather terse definition for a “command” named
forward-char with one argument, nchars.
Where the output format allows, @deffn uses a typewriter font
for name, and a slanted font for the rest of the arguments,
as would be produced by @var.
Within the text of the description, write an argument name
explicitly with @var to refer to the value of the argument.
In the example above, we used ‘@var{nchars}’ in this way.
In the extremely unusual case when an argument name contains
‘--’, or another character sequence which is treated specially
(see General Syntactic Conventions), use @code around the special
characters. This avoids the conversion to typographic en-dashes and
em-dashes.
@defun name arguments… ¶The @defun command is the definition command for functions
with simple arguments. @defun is equivalent to
‘@deffn Function …’. Terminate the definition with
@end defun on a line of its own.
@defmac name arguments… ¶The @defmac command is the definition command for macros.
@defmac is equivalent to ‘@deffn Macro …’ and
works like @defun.
@defspec name arguments… ¶The @defspec command is the definition command for special
forms. (In Lisp, a special form is an entity much like a function;
see Special Forms in GNU Emacs Lisp Reference Manual.)
@defspec is equivalent to ‘@deffn {Special Form}
…’ and works like @defun.
All these commands create entries in the index of functions.