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GNU `m4'
********

   GNU `m4' is an implementation of the traditional UNIX macro
processor.  It is mostly SVR4 compatible, although it has some
extensions (for example, handling more than 9 positional parameters to
macros).  `m4' also has builtin functions for including files, running
shell commands, doing arithmetic, etc.  Autoconf needs GNU `m4' for
generating `configure' scripts, but not for running them.

   GNU `m4' was originally written by Rene' Seindal, with subsequent
changes by Franc,ois Pinard and other volunteers on the Internet.  All
names and email addresses can be found in the file `THANKS' from the
GNU `m4' distribution.

   This is release 1.4.  It is now to be considered stable, future
releases are only meant to fix bugs, increase speed, or improve
documentation.  However...

   An experimental feature, which would improve `m4' usefulness, allows
for changing the syntax for what is a "word" in `m4'.  You should use:
     ./configure --enable-changeword

if you want this feature compiled in.  The current implementation slows
down `m4' considerably and is hardly acceptable.  So, it might go away,
do not count on it yet.

Preliminaries: Introduction and preliminaries
Syntax: Lexical and syntactic conventions
Macros: How to invoke macros
Definitions: How to define new macros
Conditionals: Conditionals and loops
Debugging: How to debug macros and input
Input Control: Input control
File Inclusion: File inclusion
Diversions: Diverting and undiverting output
Text handling: Macros for text handling
Arithmetic: Macros for doing arithmetic
UNIX commands: Macros for running UNIX commands
Miscellaneous: Miscellaneous builtin macros
Frozen files: Fast loading of frozen states
Compatibility: Compatibility with other versions of m4
Concept index: Index for many concepts
Macro index: Index for all m4 macros

--- The Detailed Node Listing --- Introduction and preliminaries

Intro: Introduction to `m4'
History: Historical references
Invoking m4: Invoking `m4'
Bugs: Problems and bugs
Manual: Using this manual

Lexical and syntactic conventions

Names: Macro names
Quoted strings: Quoting input to m4
Other tokens: Other kinds of input tokens
Comments: Comments in m4 input

How to invoke macros

Invocation: Macro invocation
Inhibiting Invocation: Preventing macro invocation
Macro Arguments: Macro arguments
Quoting Arguments: On Quoting Arguments to macros
Macro expansion: Expanding macros

How to define new macros

Define: Defining a new macro
Arguments: Arguments to macros
Pseudo Arguments: Pseudo arguments to macros
Undefine: Deleting a macro
Defn: Renaming macros
Pushdef: Temporarily redefining macros
Indir: Indirect call of macros
Builtin: Indirect call of builtins

Conditionals, loops and recursion

Ifdef: Testing if a macro is defined
Ifelse: If-else construct, or multibranch
Loops: Loops and recursion in m4

How to debug macros and input

Dumpdef: Displaying macro definitions
Trace: Tracing macro calls
Debug Levels: Controlling debugging output
Debug Output: Saving debugging output

Input control

Dnl: Deleting whitespace in input
Changequote: Changing the quote characters
Changecom: Changing the comment delimiters
Changeword: Changing the lexical structure of words
M4wrap: Saving input until end of input

File inclusion

Include: Including named files
Search Path: Searching for include files

Diverting and undiverting output

Divert: Diverting output
Undivert: Undiverting output
Divnum: Diversion numbers
Cleardiv: Discarding diverted text

Macros for text handling

Len: Calculating length of strings
Index: Searching for substrings
Regexp: Searching for regular expressions
Substr: Extracting substrings
Translit: Translating characters
Patsubst: Substituting text by regular expression
Format: Formatting strings (printf-like)

Macros for doing arithmetic

Incr: Decrement and increment operators
Eval: Evaluating integer expressions

Running UNIX commands

Syscmd: Executing simple commands
Esyscmd: Reading the output of commands
Sysval: Exit codes
Maketemp: Making names for temporary files

Miscellaneous builtin macros

Errprint: Printing error messages
M4exit: Exiting from m4

Compatibility with other versions of `m4'

Extensions: Extensions in GNU m4
Incompatibilities: Facilities in System V m4 not in GNU m4
Other Incompat: Other incompatibilities

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