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NAME

m4 − macro processor

SYNOPSIS

m4 [OPTION]... [FILE]...

DESCRIPTION

Process macros in FILEs. If no FILE or if FILE is ’−’, standard input is read.

Mandatory or optional arguments to long options are mandatory or optional for short options too.

Operation modes:

−−help

display this help and exit

−−version

output version information and exit

−E, −−fatal−warnings

once: warnings become errors, twice: stop execution at first error

−i, −−interactive

unbuffer output, ignore interrupts

−P, −−prefix−builtins

force a ’m4_’ prefix to all builtins

−Q, −−quiet, −−silent

suppress some warnings for builtins

−−warn−macro−sequence[=REGEXP]

warn if macro definition matches REGEXP,

default \$\({[^}]*}\|[0−9][0−9]+\)

−W, −−word−regexp=REGEXP

use REGEXP for macro name syntax

Preprocessor features:
−D
, −−define=NAME[=VALUE]

define NAME as having VALUE, or empty

−I, −−include=DIRECTORY

append DIRECTORY to include path

−s, −−synclines

generate ’#line NUM "FILE"’ lines

−U, −−undefine=NAME

undefine NAME

Limits control:
−g
, −−gnu

override −G to re−enable GNU extensions

−G, −−traditional

suppress all GNU extensions

−H, −−hashsize=PRIME

set symbol lookup hash table size [509]

−L, −−nesting−limit=NUMBER

change nesting limit, 0 for unlimited [0]

Frozen state files:
−F
, −−freeze−state=FILE

produce a frozen state on FILE at end

−R, −−reload−state=FILE

reload a frozen state from FILE at start

Debugging:
−d
, −−debug[=FLAGS]

set debug level (no FLAGS implies ’aeq’)

−−debugfile[=FILE]

redirect debug and trace output to FILE (default stderr, discard if empty string)

−l, −−arglength=NUM

restrict macro tracing size

−t, −−trace=NAME

trace NAME when it is defined

FLAGS is any of:

a

show actual arguments

c

show before collect, after collect and after call

e

show expansion

f

say current input file name

i

show changes in input files

l

say current input line number

p

show results of path searches

q

quote values as necessary, with a or e flag

t

trace for all macro calls, not only traceon’ed

x

add a unique macro call id, useful with c flag

V

shorthand for all of the above flags

If defined, the environment variable ’M4PATH’ is a colon−separated list of directories included after any specified by ’−I’.

Exit status is 0 for success, 1 for failure, 63 for frozen file version mismatch, or whatever value was passed to the m4exit macro.

AUTHOR

Written by Rene’ Seindal.

REPORTING BUGS

Report bugs to: bug−m4 [AT] gnu.org
GNU M4 home page: <http://www.gnu.org/software/m4/>;
General help using GNU software: <http://www.gnu.org/gethelp/>;

COPYRIGHT

Copyright © 2016 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>;.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

SEE ALSO

The full documentation for m4 is maintained as a Texinfo manual. If the info and m4 programs are properly installed at your site, the command

info m4

should give you access to the complete manual.

COMMENTS