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(m4.info)Manual

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Using this manual
=================

   This manual contains a number of examples of `m4' input and output,
and a simple notation is used to distinguish input, output and error
messages from `m4'.  Examples are set out from the normal text, and
shown in a fixed width font, like this

     This is an example of an example!

   To distinguish input from output, all output from `m4' is prefixed
by the string `=>', and all error messages by the string `error-->'.
Thus

     Example of input line
     =>Output line from m4
     error-->and an error message

   As each of the predefined macros in `m4' is described, a prototype
call of the macro will be shown, giving descriptive names to the
arguments, e.g.,

     regexp(STRING, REGEXP, opt REPLACEMENT)

   All macro arguments in `m4' are strings, but some are given special
interpretation, e.g., as numbers, filenames, regular expressions, etc.

   The `opt' before the third argument shows that this argument is
optional--if it is left out, it is taken to be the empty string.  An
ellipsis (`...') last in the argument list indicates that any number of
arguments may follow.

   This document consistently writes and uses "builtin", without an
hyphen, as if it were an English word.  This is how the `builtin'
primitive is spelled within `m4'.