M4

Section: User Commands (1)
Updated: December 2016
Page Index

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@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.

M4