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8.2.1 Invoking `autom4te'
The command line arguments are modeled after M4's:
autom4te OPTIONS FILES
where the FILES are directly passed to `m4'. By default, GNU M4 is
found during configuration, but the environment variable `M4' can be
set to tell `autom4te' where to look. In addition to the regular
expansion, it handles the replacement of the quadrigraphs (*note
Quadrigraphs::), and of `__oline__', the current line in the output.
It supports an extended syntax for the FILES:
This file is an M4 frozen file. Note that _all the previous files
are ignored_. See the option `--melt' for the rationale.
If found in the library path, the FILE is included for expansion,
otherwise it is ignored instead of triggering a failure.
Of course, it supports the Autoconf common subset of options:
Print a summary of the command line options and exit.
Print the version number of Autoconf and exit.
Report processing steps.
Don't remove the temporary files and be even more verbose.
Also look for input files in DIR. Multiple invocations accumulate.
Save output (script or trace) to FILE. The file `-' stands for
the standard output.
As an extension of `m4', it includes the following options:
Report the warnings related to CATEGORY (which can actually be a
comma separated list). Note: Reporting Messages, macro
`AC_DIAGNOSE', for a comprehensive list of categories. Special
report all the warnings
treats warnings as errors
disable warnings falling into CATEGORY
Warnings about `syntax' are enabled by default, and the environment
variable `WARNINGS', a comma separated list of categories, is
honored. `autom4te -W CATEGORY' actually behaves as if you had
For example, if you want to disable defaults and `WARNINGS' of
`autom4te', but enable the warnings about obsolete constructs, you
would use `-W none,obsolete'.
`autom4te' displays a back trace for errors, but not for warnings;
if you want them, just pass `-W error'.
Do not use frozen files. Any argument `FILE.m4f' is replaced by
`FILE.m4'. This helps tracing the macros which are executed only
when the files are frozen, typically `m4_define'. For instance,
autom4te --melt 1.m4 2.m4f 3.m4 4.m4f input.m4
is roughly equivalent to running:
m4 1.m4 2.m4 3.m4 4.m4 input.m4
autom4te 1.m4 2.m4f 3.m4 4.m4f input.m4
is equivalent to:
m4 --reload-state=4.m4f input.m4
Produce a frozen state file. `autom4te' freezing is stricter than
M4's: it must produce no warnings, and no output other than empty
lines (a line with white space is _not_ empty) and comments
(starting with `#'). Unlike `m4''s similarly-named option, this
option takes no argument:
autom4te 1.m4 2.m4 3.m4 --freeze --output=3.m4f
m4 1.m4 2.m4 3.m4 --freeze-state=3.m4f
Set the mode of the non-traces output to OCTAL-MODE; by default
As another additional feature over `m4', `autom4te' caches its
results. GNU M4 is able to produce a regular output and traces at the
same time. Traces are heavily used in the GNU Build System:
`autoheader' uses them to build `config.h.in', `autoreconf' to
determine what GNU Build System components are used, `automake' to
"parse" `configure.ac' etc. To avoid recomputation, traces are cached
while performing regular expansion, and conversely. This cache is
(actually, the caches are) stored in the directory `autom4te.cache'.
_It can safely be removed_ at any moment (especially if for some reason
`autom4te' considers it trashed).
Specify the name of the directory where the result should be
cached. Passing an empty value disables caching. Be sure to pass
a relative file name, as for the time being, global caches are not
Don't cache the results.
If a cache is used, consider it obsolete (but update it anyway).
Because traces are so important to the GNU Build System, `autom4te'
provides high level tracing features as compared to M4, and helps
exploiting the cache:
Trace the invocations of MACRO according to the FORMAT. Multiple
`--trace' arguments can be used to list several macros. Multiple
`--trace' arguments for a single macro are not cumulative;
instead, you should just make FORMAT as long as needed.
The FORMAT is a regular string, with newlines if desired, and
several special escape codes. It defaults to `$f:$l:$n:$%'. It
can use the following special escapes:
The character `$'.
The file name from which MACRO is called.
The line number from which MACRO is called.
The depth of the MACRO call. This is an M4 technical detail
that you probably don't want to know about.
The name of the MACRO.
The NUMth argument of the call to MACRO.
All the arguments passed to MACRO, separated by the character
SEP or the string SEPARATOR (`,' by default). Each argument
is quoted, i.e., enclosed in a pair of square brackets.
As above, but the arguments are not quoted.
As above, but the arguments are not quoted, all new line
characters in the arguments are smashed, and the default
separator is `:'.
The escape `$%' produces single-line trace outputs (unless
you put newlines in the `separator'), while `$@' and `$*' do
Note: autoconf Invocation, for examples of trace uses.
Cache the traces of MACRO, but do not enable traces. This is
especially important to save CPU cycles in the future. For
instance, when invoked, `autoconf' preselects all the macros that
`autoheader', `automake', `autoreconf', etc., trace, so that
running `m4' is not needed to trace them: the cache suffices.
This results in a huge speed-up.
Finally, `autom4te' introduces the concept of "Autom4te libraries".
They consists in a powerful yet extremely simple feature: sets of
combined command line arguments:
Use the LANGUAGE Autom4te library. Current languages include:
create M4sugar output.
create M4sh executable shell scripts.
create Autotest executable test suites.
create Autoconf executable configure scripts without reading
create Autoconf executable configure scripts. This language
inherits all the characteristics of
`Autoconf-without-aclocal-m4' and additionally reads
Prepend directory DIR to the search path. This is used to include
the language-specific files before any third-party macros.
As an example, if Autoconf is installed in its default location,
`/usr/local', the command `autom4te -l m4sugar foo.m4' is strictly
equivalent to the command:
autom4te --prepend-include /usr/local/share/autoconf \
m4sugar/m4sugar.m4f --warnings syntax foo.m4
Recursive expansion applies here: the command `autom4te -l m4sh foo.m4'
is the same as `autom4te --language M4sugar m4sugar/m4sh.m4f foo.m4',
autom4te --prepend-include /usr/local/share/autoconf \
m4sugar/m4sugar.m4f m4sugar/m4sh.m4f --mode 777 foo.m4
The definition of the languages is stored in `autom4te.cfg'.
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