This manual is for GNU Automake (version 1.8.2, 7 January 2004), a program which creates GNU standards-compliant Makefiles from template files.
Copyright © 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover texts being “A GNU Manual,” and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License.”(a) The FSF's Back-Cover Text is: “You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.”
--- The Detailed Node Listing ---
General ideas
Some example packages
Scanning configure.ac
Auto-generating aclocal.m4
Autoconf macros supplied with Automake
Building Programs and Libraries
Building a program
Building a Shared Library
Fortran 77 Support
Mixing Fortran 77 With C and C++
Other Derived Objects
Built sources
Other GNU Tools
Building documentation
Miscellaneous Rules
Frequently Asked Questions about Automake
Copying This Manual
Indices
Automake is a tool for automatically generating Makefile.ins from
files called Makefile.am. Each Makefile.am is basically a
series of make variable definitions1, with
rules being thrown in occasionally. The generated Makefile.ins
are compliant with the GNU Makefile standards.
The GNU Makefile Standards Document (see Makefile Conventions (The GNU Coding Standards)) is long, complicated, and subject to change. The goal of Automake is to remove the burden of Makefile maintenance from the back of the individual GNU maintainer (and put it on the back of the Automake maintainer).
The typical Automake input file is simply a series of variable definitions. Each such file is processed to create a Makefile.in. There should generally be one Makefile.am per directory of a project.
Automake does constrain a project in certain ways; for instance it assumes that the project uses Autoconf (see Introduction (The Autoconf Manual)), and enforces certain restrictions on the configure.ac contents2.
Automake requires perl in order to generate the
Makefile.ins. However, the distributions created by Automake are
fully GNU standards-compliant, and do not require perl in order
to be built.
Mail suggestions and bug reports for Automake to bug-automake@gnu.org.
The following sections cover a few basic ideas that will help you understand how Automake works.
Automake works by reading a Makefile.am and generating a Makefile.in. Certain variables and rules defined in the Makefile.am instruct Automake to generate more specialized code; for instance, a bin_PROGRAMS variable definition will cause rules for compiling and linking programs to be generated.
The variable definitions and rules in the Makefile.am are
copied verbatim into the generated file. This allows you to add
arbitrary code into the generated Makefile.in. For instance
the Automake distribution includes a non-standard rule for the
cvs-dist target, which the Automake maintainer uses to make
distributions from his source control system.
Note that most GNU make extensions are not recognized by Automake. Using such extensions in a Makefile.am will lead to errors or confusing behavior.
A special exception is that the GNU make append operator, +=, is supported. This operator appends its right hand argument to the variable specified on the left. Automake will translate the operator into an ordinary = operator; += will thus work with any make program.
Automake tries to keep comments grouped with any adjoining rules or variable definitions.
A rule defined in Makefile.am generally overrides any such
rule of a similar name that would be automatically generated by
automake. Although this is a supported feature, it is generally
best to avoid making use of it, as sometimes the generated rules are
very particular.
Similarly, a variable defined in Makefile.am or
AC_SUBST'ed from configure.ac will override any
definition of the variable that automake would ordinarily
create. This feature is more often useful than the ability to
override a rule. Be warned that many of the variables generated by
automake are considered to be for internal use only, and their
names might change in future releases.
When examining a variable definition, Automake will recursively examine
variables referenced in the definition. For example, if Automake is
looking at the content of foo_SOURCES in this snippet
xs = a.c b.c
foo_SOURCES = c.c $(xs)
it would use the files a.c, b.c, and c.c as the
contents of foo_SOURCES.
Automake also allows a form of comment which is not copied into the output; all lines beginning with ## (leading spaces allowed) are completely ignored by Automake.
It is customary to make the first line of Makefile.am read:
## Process this file with automake to produce Makefile.in
While Automake is intended to be used by maintainers of GNU packages, it does make some effort to accommodate those who wish to use it, but do not want to use all the GNU conventions.
To this end, Automake supports three levels of strictness—the strictness indicating how stringently Automake should check standards conformance.
The valid strictness levels are:
For more information on the precise implications of the strictness level, see Gnits.
Automake also has a special “cygnus” mode which is similar to strictness but handled differently. This mode is useful for packages which are put into a “Cygnus” style tree (e.g., the GCC tree). For more information on this mode, see Cygnus.
Automake variables generally follow a uniform naming scheme that
makes it easy to decide how programs (and other derived objects) are
built, and how they are installed. This scheme also supports
configure time determination of what should be built.
At make time, certain variables are used to determine which
objects are to be built. The variable names are made of several pieces
which are concatenated together.
The piece which tells automake what is being built is commonly called
the primary. For instance, the primary PROGRAMS holds a
list of programs which are to be compiled and linked.
A different set of names is used to decide where the built objects
should be installed. These names are prefixes to the primary which
indicate which standard directory should be used as the installation
directory. The standard directory names are given in the GNU standards
(see Directory Variables (The GNU Coding Standards)).
Automake extends this list with pkglibdir, pkgincludedir,
and pkgdatadir; these are the same as the non-pkg
versions, but with $(PACKAGE) appended. For instance,
pkglibdir is defined as $(libdir)/$(PACKAGE).
For each primary, there is one additional variable named by prepending
EXTRA_ to the primary name. This variable is used to list
objects which may or may not be built, depending on what
configure decides. This variable is required because Automake
must statically know the entire list of objects that may be built in
order to generate a Makefile.in that will work in all cases.
For instance, cpio decides at configure time which programs are
built. Some of the programs are installed in bindir, and some
are installed in sbindir:
EXTRA_PROGRAMS = mt rmt
bin_PROGRAMS = cpio pax
sbin_PROGRAMS = $(MORE_PROGRAMS)
Defining a primary without a prefix as a variable, e.g.,
PROGRAMS, is an error.
Note that the common dir suffix is left off when constructing the variable names; thus one writes bin_PROGRAMS and not bindir_PROGRAMS.
Not every sort of object can be installed in every directory. Automake will flag those attempts it finds in error. Automake will also diagnose obvious misspellings in directory names.
Sometimes the standard directories—even as augmented by Automake—
are not enough. In particular it is sometimes useful, for clarity, to
install objects in a subdirectory of some predefined directory. To this
end, Automake allows you to extend the list of possible installation
directories. A given prefix (e.g. zar) is valid if a variable of
the same name with dir appended is defined (e.g. zardir).
For instance, installation of HTML files is part of Automake, you could use this to install raw HTML documentation:
htmldir = $(prefix)/html
html_DATA = automake.html
The special prefix noinst indicates that the objects in question should be built but not installed at all. This is usually used for objects required to build the rest of your package, for instance static libraries (see A Library), or helper scripts.
The special prefix check indicates that the objects in question
should not be built until the make check command is run. Those
objects are not installed either.
The current primary names are PROGRAMS, LIBRARIES,
LISP, PYTHON, JAVA, SCRIPTS, DATA,
HEADERS, MANS, and TEXINFOS.
Some primaries also allow additional prefixes which control other
aspects of automake's behavior. The currently defined prefixes
are dist_, nodist_, and nobase_. These prefixes
are explained later (see Program and Library Variables).
Sometimes a Makefile variable name is derived from some text the maintainer supplies. For instance, a program name listed in _PROGRAMS is rewritten into the name of a _SOURCES variable. In cases like this, Automake canonicalizes the text, so that program names and the like do not have to follow Makefile variable naming rules. All characters in the name except for letters, numbers, the strudel (@), and the underscore are turned into underscores when making variable references.
For example, if your program is named sniff-glue, the derived
variable name would be sniff_glue_SOURCES, not
sniff-glue_SOURCES. Similarly the sources for a library named
libmumble++.a should be listed in the
libmumble___a_SOURCES variable.
The strudel is an addition, to make the use of Autoconf substitutions in variable names less obfuscating.
Some Makefile variables are reserved by the GNU Coding Standards
for the use of the “user” – the person building the package. For
instance, CFLAGS is one such variable.
Sometimes package developers are tempted to set user variables such as
CFLAGS because it appears to make their job easier. However,
the package itself should never set a user variable, particularly not
to include switches which are required for proper compilation of the
package. Since these variables are documented as being for the
package builder, that person rightfully expects to be able to override
any of these variables at build time.
To get around this problem, automake introduces an automake-specific
shadow variable for each user flag variable. (Shadow variables are not
introduced for variables like CC, where they would make no
sense.) The shadow variable is named by prepending AM_ to the
user variable's name. For instance, the shadow variable for
YFLAGS is AM_YFLAGS.
Automake sometimes requires helper programs so that the generated Makefile can do its work properly. There are a fairly large number of them, and we list them here.
ansi2knr.cansi2knr.1compileconfig.guessconfig.subdepcompelisp-compinstall-shinstall program which works on
platforms where install is unavailable or unusable.
mdate-shmissingmissing
prints an informative warning and attempts to fix things so that the
build can continue.
mkinstalldirsmkdir -p, which is not
portable. Now we use prefer to use install-sh -d when configure
finds that mkdir -p does not work, this makes one less script to
distribute.
For backward compatibility mkinstalldirs is still used and
distributed when automake finds it in a package. But it is no
longer installed automatically, and it should be safe to remove it.
py-compiletexinfo.texmake dvi, make ps
and make pdf to work when Texinfo sources are in the package.
ylwraplex and yacc and ensures that, for
instance, multiple yacc instances can be invoked in a single
directory in parallel.
Let's suppose you just finished writing zardoz, a program to make
your head float from vortex to vortex. You've been using Autoconf to
provide a portability framework, but your Makefile.ins have been
ad-hoc. You want to make them bulletproof, so you turn to Automake.
The first step is to update your configure.ac to include the
commands that automake needs. The way to do this is to add an
AM_INIT_AUTOMAKE call just after AC_INIT:
AC_INIT(zardoz, 1.0)
AM_INIT_AUTOMAKE
...
Since your program doesn't have any complicating factors (e.g., it
doesn't use gettext, it doesn't want to build a shared library),
you're done with this part. That was easy!
Now you must regenerate configure. But to do that, you'll need
to tell autoconf how to find the new macro you've used. The
easiest way to do this is to use the aclocal program to generate
your aclocal.m4 for you. But wait... maybe you already have an
aclocal.m4, because you had to write some hairy macros for your
program. The aclocal program lets you put your own macros into
acinclude.m4, so simply rename and then run:
mv aclocal.m4 acinclude.m4
aclocal
autoconf
Now it is time to write your Makefile.am for zardoz.
Since zardoz is a user program, you want to install it where the
rest of the user programs go: bindir. Additionally,
zardoz has some Texinfo documentation. Your configure.ac
script uses AC_REPLACE_FUNCS, so you need to link against
$(LIBOBJS). So here's what you'd write:
bin_PROGRAMS = zardoz
zardoz_SOURCES = main.c head.c float.c vortex9.c gun.c
zardoz_LDADD = $(LIBOBJS)
info_TEXINFOS = zardoz.texi
Now you can run automake --add-missing to generate your
Makefile.in and grab any auxiliary files you might need, and
you're done!
GNU hello is renowned for its classic simplicity and versatility. This section shows how Automake could be used with the GNU Hello package. The examples below are from the latest beta version of GNU Hello, but with all of the maintainer-only code stripped out, as well as all copyright comments.
Of course, GNU Hello is somewhat more featureful than your traditional two-liner. GNU Hello is internationalized, does option processing, and has a manual and a test suite.
Here is the configure.ac from GNU Hello.
Please note: The calls to AC_INIT and AM_INIT_AUTOMAKE
in this example use a deprecated syntax. For the current approach,
see the description of AM_INIT_AUTOMAKE in Public macros.
dnl Process this file with autoconf to produce a configure script.
AC_INIT(src/hello.c)
AM_INIT_AUTOMAKE(hello, 1.3.11)
AM_CONFIG_HEADER(config.h)
dnl Set of available languages.
ALL_LINGUAS="de fr es ko nl no pl pt sl sv"
dnl Checks for programs.
AC_PROG_CC
AC_ISC_POSIX
dnl Checks for libraries.
dnl Checks for header files.
AC_STDC_HEADERS
AC_HAVE_HEADERS(string.h fcntl.h sys/file.h sys/param.h)
dnl Checks for library functions.
AC_FUNC_ALLOCA
dnl Check for st_blksize in struct stat
AC_ST_BLKSIZE
dnl internationalization macros
AM_GNU_GETTEXT
AC_OUTPUT([Makefile doc/Makefile intl/Makefile po/Makefile.in \
src/Makefile tests/Makefile tests/hello],
[chmod +x tests/hello])
The AM_ macros are provided by Automake (or the Gettext library); the rest are standard Autoconf macros.
The top-level Makefile.am:
EXTRA_DIST = BUGS ChangeLog.O
SUBDIRS = doc intl po src tests
As you can see, all the work here is really done in subdirectories.
The po and intl directories are automatically generated
using gettextize; they will not be discussed here.
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
This is sufficient to build, install, and distribute the GNU Hello manual.
TESTS = hello
EXTRA_DIST = hello.in testdata
The script hello is generated by configure, and is the
only test case. make check will run this test.
Last we have src/Makefile.am, where all the real work is done:
bin_PROGRAMS = hello
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h
hello_LDADD = $(INTLLIBS) $(ALLOCA)
localedir = $(datadir)/locale
INCLUDES = -I../intl -DLOCALEDIR=\"$(localedir)\"
Here is another, trickier example. It shows how to generate two
programs (true and false) from the same source file
(true.c). The difficult part is that each compilation of
true.c requires different cpp flags.
bin_PROGRAMS = true false
false_SOURCES =
false_LDADD = false.o
true.o: true.c
$(COMPILE) -DEXIT_CODE=0 -c true.c
false.o: true.c
$(COMPILE) -DEXIT_CODE=1 -o false.o -c true.c
Note that there is no true_SOURCES definition. Automake will
implicitly assume that there is a source file named true.c, and
define rules to compile true.o and link true. The
true.o: true.c rule supplied by the above Makefile.am,
will override the Automake generated rule to build true.o.
false_SOURCES is defined to be empty—that way no implicit value
is substituted. Because we have not listed the source of
false, we have to tell Automake how to link the program. This is
the purpose of the false_LDADD line. A false_DEPENDENCIES
variable, holding the dependencies of the false target will be
automatically generated by Automake from the content of
false_LDADD.
The above rules won't work if your compiler doesn't accept both
-c and -o. The simplest fix for this is to introduce a
bogus dependency (to avoid problems with a parallel make):
true.o: true.c false.o
$(COMPILE) -DEXIT_CODE=0 -c true.c
false.o: true.c
$(COMPILE) -DEXIT_CODE=1 -c true.c && mv true.o false.o
Also, these explicit rules do not work if the de-ANSI-fication feature is used (see ANSI). Supporting de-ANSI-fication requires a little more work:
true._o: true._c false.o
$(COMPILE) -DEXIT_CODE=0 -c true.c
false._o: true._c
$(COMPILE) -DEXIT_CODE=1 -c true.c && mv true._o false.o
As it turns out, there is also a much easier way to do this same task.
Some of the above techniques are useful enough that we've kept the
example in the manual. However if you were to build true and
false in real life, you would probably use per-program
compilation flags, like so:
bin_PROGRAMS = false true
false_SOURCES = true.c
false_CPPFLAGS = -DEXIT_CODE=1
true_SOURCES = true.c
true_CPPFLAGS = -DEXIT_CODE=0
In this case Automake will cause true.c to be compiled twice, with different flags. De-ANSI-fication will work automatically. In this instance, the names of the object files would be chosen by automake; they would be false-true.o and true-true.o. (The name of the object files rarely matters.)
To create all the Makefile.ins for a package, run the
automake program in the top level directory, with no arguments.
automake will automatically find each appropriate
Makefile.am (by scanning configure.ac; see configure)
and generate the corresponding Makefile.in. Note that
automake has a rather simplistic view of what constitutes a
package; it assumes that a package has only one configure.ac, at
the top. If your package has multiple configure.acs, then you
must run automake in each directory holding a
configure.ac. (Alternatively, you may rely on Autoconf's
autoreconf, which is able to recurse your package tree and run
automake where appropriate.)
You can optionally give automake an argument; .am is
appended to the argument and the result is used as the name of the input
file. This feature is generally only used to automatically rebuild an
out-of-date Makefile.in. Note that automake must always
be run from the topmost directory of a project, even if being used to
regenerate the Makefile.in in some subdirectory. This is
necessary because automake must scan configure.ac, and
because automake uses the knowledge that a Makefile.in is
in a subdirectory to change its behavior in some cases.
Automake will run autoconf to scan configure.ac and its
dependencies (aclocal.m4), therefore autoconf must be in
your PATH. If there is an AUTOCONF variable in your
environment it will be used instead of autoconf, this allows you
to select a particular version of Autoconf. By the way, don't
misunderstand this paragraph: Automake runs autoconf to
scan your configure.ac, this won't build
configure and you still have to run autoconf yourself for
this purpose.
automake accepts the following options:
AC_CANONICAL_HOST. Automake is distributed with several of these
files (see Auxiliary Programs); this option will cause the missing
ones to be automatically added to the package, whenever possible. In
general if Automake tells you a file is missing, try using this option.
By default Automake tries to make a symbolic link pointing to its own
copy of the missing file; this can be changed with --copy.
Many of the potentially-missing files are common scripts whose
location may be specified via the AC_CONFIG_AUX_DIR macro.
Therefore, AC_CONFIG_AUX_DIR's setting affects whether a
file is considered missing, and where the missing file is added
(see Optional).
--add-missing, causes installed files to be
copied. The default is to make a symbolic link.
--add-missing, causes standard files to be reinstalled
even if they already exist in the source tree. This involves removing
the file from the source tree before creating the new symlink (or, with
--copy, copying the new file).
automake creates all Makefile.ins mentioned in
configure.ac. This option causes it to only update those
Makefile.ins which are out of date with respect to one of their
dependents.
A category can be turned off by prefixing its name with no-. For instance -Wno-syntax will hide the warnings about unused variables.
The categories output by default are syntax and unsupported. Additionally, gnu is enabled in --gnu and --gnits strictness.
portability warnings are currently disabled by default, but they will be enabled in --gnu and --gnits strictness in a future release.
The environment variable WARNINGS can contain a comma separated list of categories to enable. It will be taken into account before the command-line switches, this way -Wnone will also ignore any warning category enabled by WARNINGS. This variable is also used by other tools like autoconf; unknown categories are ignored for this reason.
Automake scans the package's configure.ac to determine certain
information about the package. Some autoconf macros are required
and some variables must be defined in configure.ac. Automake
will also use information from configure.ac to further tailor its
output.
Automake also supplies some Autoconf macros to make the maintenance
easier. These macros can automatically be put into your
aclocal.m4 using the aclocal program.
The one real requirement of Automake is that your configure.ac
call AM_INIT_AUTOMAKE. This macro does several things which are
required for proper Automake operation (see Macros).
Here are the other macros which Automake requires but which are not run
by AM_INIT_AUTOMAKE:
AC_CONFIG_FILESAC_OUTPUTAC_CONFIG_FILES([foo/Makefile]) will cause Automake to
generate foo/Makefile.in if foo/Makefile.am exists.
When using AC_CONFIG_FILES with multiple input files, as in
AC_CONFIG_FILES([Makefile:top.in:Makefile.in:bot.in]), Automake
will generate the first .in input file for which a .am
file exists. If no such file exists the output file is not considered
to be Automake generated.
Files created by AC_CONFIG_FILES are removed by make distclean.
Every time Automake is run it calls Autoconf to trace configure.ac. This way it can recognize the use of certain macros and tailor the generated Makefile.in appropriately. Currently recognized macros and their effects are:
AC_CONFIG_HEADERSAM_CONFIG_HEADER
(see Macros); this is no longer the case today.
AC_CONFIG_LINKSmake distclean and to distribute named source files as part of
make dist.
AC_CONFIG_AUX_DIRAC_CONFIG_AUX_DIR is not given, the scripts are looked for in
their standard locations. For mdate-sh,
texinfo.tex, and ylwrap, the standard location is the
source directory corresponding to the current Makefile.am. For
the rest, the standard location is the first one of ., ..,
or ../.. (relative to the top source directory) that provides any
one of the helper scripts. See Finding `configure' Input (The Autoconf Manual).
Required files from AC_CONFIG_AUX_DIR are automatically
distributed, even if there is no Makefile.am in this directory.
AC_CANONICAL_HOSTAC_CANONICAL_SYSTEMAC_CANONICAL_HOST, but also defines the
Makefile variables build_alias and target_alias.
See Getting the Canonical System Type (The Autoconf Manual).
AC_LIBSOURCEAC_LIBSOURCESAC_LIBOBJAC_LIBSOURCE or AC_LIBSOURCES.
Note that the AC_LIBOBJ macro calls AC_LIBSOURCE. So if
an Autoconf macro is documented to call AC_LIBOBJ([file]), then
file.c will be distributed automatically by Automake. This
encompasses many macros like AC_FUNC_ALLOCA,
AC_FUNC_MEMCMP, AC_REPLACE_FUNCS, and others.
By the way, direct assignments to LIBOBJS are no longer
supported. You should always use AC_LIBOBJ for this purpose.
See AC_LIBOBJ vs. LIBOBJS (The Autoconf Manual).
AC_PROG_RANLIBAC_PROG_CXXAC_PROG_F77AC_F77_LIBRARY_LDFLAGSAC_PROG_LIBTOOLlibtool (see Introduction (The Libtool Manual)).
AC_PROG_YACCAC_PROG_LEXAC_SUBSTIf the Autoconf manual says that a macro calls AC_SUBST for
var, or defines the output variable var then var will
be defined in each Makefile.in generated by Automake.
E.g. AC_PATH_XTRA defines X_CFLAGS and X_LIBS, so
you can use these variables in any Makefile.am if
AC_PATH_XTRA is called.
AM_C_PROTOTYPESAM_GNU_GETTEXTAM_MAINTAINER_MODEconfigure. If this is used, automake will cause
maintainer-only rules to be turned off by default in the
generated Makefile.ins. This macro defines the
MAINTAINER_MODE conditional, which you can use in your own
Makefile.am.
m4_includem4_include is seldom used by configure.ac authors, but
can appear in aclocal.m4 when aclocal detects that
some required macros come from files local to your package (as
opposed to macros installed in a system-wide directory, see
Invoking aclocal).
Automake includes a number of Autoconf macros which can be used in your package (see Macros); some of them are actually required by Automake in certain situations. These macros must be defined in your aclocal.m4; otherwise they will not be seen by autoconf.
The aclocal program will automatically generate aclocal.m4 files based on the contents of configure.ac. This provides a convenient way to get Automake-provided macros, without having to search around. The aclocal mechanism allows other packages to supply their own macros (see Extending aclocal). You can also use it to maintain your own set of custom macros (see Local Macros).
At startup, aclocal scans all the .m4 files it can find, looking for macro definitions (see Macro search path). Then it scans configure.ac. Any mention of one of the macros found in the first step causes that macro, and any macros it in turn requires, to be put into aclocal.m4.
Putting the file that contains the macro definition into aclocal.m4 is usually done by copying the entire text of this file, including unused macro definitions as well as both # and dnl comments. If you want to make a comment which will be completely ignored by aclocal, use ## as the comment leader.
When aclocal detects that the file containing the macro
definition is in a subdirectory of your package, it will use
m4_include instead of copying it; this makes the package
smaller and eases dependency tracking. This only works if the
subdirectory containing the macro was specified as a relative search
path with aclocal's -I argument. (see Local Macros for an example.) Any macro which is found in a system-wide
directory, or via an absolute search path will be copied.
The contents of acinclude.m4, if it exists, are also automatically included in aclocal.m4. We recommend against using acinclude.m4 in new packages (see Local Macros).
While computing aclocal.m4, aclocal runs autom4te
(see Using Autom4te (The Autoconf Manual)) in order to trace the macros which are really used,
and omit from aclocal.m4 all macros which are mentioned but
otherwise unexpanded (this can happen when a macro is called
conditionally). autom4te is expected to be in the PATH,
just as autoconf. Its location can be overridden using the
AUTOM4TE environment variable.
aclocal accepts the following options:
--acdir=dir--help-I dir--force--output=file--print-ac-diraclocal will search to
find third-party .m4 files. When this option is given, normal
processing is suppressed. This option can be used by a package to
determine where to install a macro file.
--verbose--versionBy default, aclocal searches for .m4 files in the following directories, in this order:
1.6.
--print-ac-dir option
(see aclocal options).
As an example, suppose that automake-1.6.2 was configured with
--prefix=/usr/local. Then, the search path would be:
As explained in (see aclocal options), there are several options that can be used to change or extend this search path.
--acdirThe most obvious option to modify the search path is
--acdir=dir, which changes default directory and
drops the APIVERSION directory. For example, if one specifies
--acdir=/opt/private/, then the search path becomes:
Note that this option, --acdir, is intended for use
by the internal automake test suite only; it is not ordinarily
needed by end-users.
-I dirAny extra directories specified using -I options
(see aclocal options) are prepended to this search list. Thus,
aclocal -I /foo -I /bar results in the following search path:
There is a third mechanism for customizing the search path. If a dirlist file exists in acdir, then that file is assumed to contain a list of directories, one per line, to be added to the search list. These directories are searched after all other directories.
For example, suppose acdir/dirlist contains the following:
/test1
/test2
and that aclocal was called with the -I /foo -I /bar options.
Then, the search path would be
If the --acdir=dir option is used, then aclocal
will search for the dirlist file in dir. In the
--acdir=/opt/private/ example above, aclocal would look
for /opt/private/dirlist. Again, however, the --acdir
option is intended for use by the internal automake test suite only;
--acdir is not ordinarily needed by end-users.
dirlist is useful in the following situation: suppose that
automake version 1.6.2 is installed with
$prefix=/usr by the system vendor. Thus, the default search
directories are
However, suppose further that many packages have been manually
installed on the system, with $prefix=/usr/local, as is typical.
In that case, many of these “extra” .m4 files are in
/usr/local/share/aclocal. The only way to force
/usr/bin/aclocal to find these “extra” .m4 files
is to always call aclocal -I /usr/local/share/aclocal.
This is inconvenient. With dirlist, one may create the file
/usr/share/aclocal/dirlist
which contains only the single line
/usr/local/share/aclocal
Now, the “default” search path on the affected system is
without the need for -I options; -I options can be reserved
for project-specific needs (my-source-dir/m4/), rather than
using it to work around local system-dependent tool installation
directories.
Similarly, dirlist can be handy if you have installed a local copy Automake on your account and want aclocal to look for macros installed at other places on the system.
Automake ships with several Autoconf macros that you can use from your
configure.ac. When you use one of them it will be included by
aclocal in aclocal.m4.
AM_CONFIG_HEADERAC_CONFIG_HEADERS
today (see Optional).
AM_ENABLE_MULTILIBAM_C_PROTOTYPESAM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTLTIOCGWINSZ requires <sys/ioctl.h>, then
define GWINSZ_IN_SYS_IOCTL. Otherwise TIOCGWINSZ can be
found in <termios.h>.
AM_INIT_AUTOMAKE([OPTIONS])AM_INIT_AUTOMAKE(PACKAGE, VERSION, [NO-DEFINE])This macro has two forms, the first of which is preferred.
In this form, AM_INIT_AUTOMAKE is called with a
single argument — a space-separated list of Automake options which should
be applied to every Makefile.am in the tree. The effect is as if
each option were listed in AUTOMAKE_OPTIONS.
The second, deprecated, form of AM_INIT_AUTOMAKE has two required
arguments: the package and the version number. This form is
obsolete because the package and version can be obtained
from Autoconf's AC_INIT macro (which itself has an old and a new
form).
If your configure.ac has:
AC_INIT(src/foo.c)
AM_INIT_AUTOMAKE(mumble, 1.5)
you can modernize it as follows:
AC_INIT(mumble, 1.5)
AC_CONFIG_SRCDIR(src/foo.c)
AM_INIT_AUTOMAKE
Note that if you're upgrading your configure.ac from an earlier
version of Automake, it is not always correct to simply move the package
and version arguments from AM_INIT_AUTOMAKE directly to
AC_INIT, as in the example above. The first argument to
AC_INIT should be the name of your package (e.g. GNU Automake),
not the tarball name (e.g. automake) that you used to pass to
AM_INIT_AUTOMAKE. Autoconf tries to derive a tarball name from
the package name, which should work for most but not all package names.
(If it doesn't work for yours, you can use the
four-argument form of AC_INIT — supported in Autoconf versions
greater than 2.52g — to provide the tarball name explicitly).
By default this macro AC_DEFINE's PACKAGE and
VERSION. This can be avoided by passing the no-define
option, as in:
AM_INIT_AUTOMAKE([gnits 1.5 no-define dist-bzip2])
or by passing a third non-empty argument to the obsolete form.
AM_PATH_LISPDIRemacs, and, if found, sets the output
variable lispdir to the full path to Emacs' site-lisp directory.
Note that this test assumes the emacs found to be a version that
supports Emacs Lisp (such as gnu Emacs or XEmacs). Other emacsen
can cause this test to hang (some, like old versions of MicroEmacs,
start up in interactive mode, requiring C-x C-c to exit, which
is hardly obvious for a non-emacs user). In most cases, however, you
should be able to use C-c to kill the test. In order to avoid
problems, you can set EMACS to “no” in the environment, or
use the --with-lispdir option to configure to
explicitly set the correct path (if you're sure you have an emacs
that supports Emacs Lisp.
AM_PROG_ASCCAS, and will also set CCASFLAGS if required.
AM_PROG_CC_C_OAC_PROG_CC_C_O, but it generates its results in the
manner required by automake. You must use this instead of
AC_PROG_CC_C_O when you need this functionality.
AM_PROG_LEXAC_PROG_LEX (see Particular Program Checks (The Autoconf Manual)), but uses the
missing script on systems that do not have lex.
HP-UX 10 is one such system.
AM_PROG_GCJgcj program or causes an error. It sets
GCJ and GCJFLAGS. gcj is the Java front-end to the
GNU Compiler Collection.
AM_SYS_POSIX_TERMIOSam_cv_sys_posix_termios to
yes. If not, set the variable to no.
AM_WITH_DMALLOCWITH_DMALLOC and add -ldmalloc to LIBS.
AM_WITH_REGEXconfigure command line. If
specified (the default), then the regex regular expression
library is used, regex.o is put into LIBOBJS, and
WITH_REGEX is defined. If --without-regex is given, then
the rx regular expression library is used, and rx.o is put
into LIBOBJS.
The following macros are private macros you should not call directly. They are called by the other public macros when appropriate. Do not rely on them, as they might be changed in a future version. Consider them as implementation details; or better, do not consider them at all: skip this section!
_AM_DEPENDENCIESAM_SET_DEPDIRAM_DEP_TRACKAM_OUTPUT_DEPENDENCY_COMMANDSAM_MAKE_INCLUDEmake handles
include statements. This macro is automatically invoked when
needed; there should be no need to invoke it manually.
AM_PROG_INSTALL_STRIPinstall which can be used to
strip a program at installation time. This macro is
automatically included when required.
AM_SANITY_CHECKAM_INIT_AUTOMAKE.
The aclocal program doesn't have any built-in knowledge of any macros, so it is easy to extend it with your own macros.
This can be used by libraries which want to supply their own Autoconf
macros for use by other programs. For instance the gettext
library supplies a macro AM_GNU_GETTEXT which should be used by
any package using gettext. When the library is installed, it
installs this macro so that aclocal will find it.
A macro file's name should end in .m4. Such files should be installed in $(datadir)/aclocal. This is as simple as writing:
aclocaldir = $(datadir)/aclocal
aclocal_DATA = mymacro.m4 myothermacro.m4
A file of macros should be a series of properly quoted
AC_DEFUN's (see Macro Definitions (The Autoconf Manual)). The aclocal programs also understands
AC_REQUIRE (see Prerequisite Macros (The Autoconf Manual)), so it is safe to put each macro in a separate file.
Each file should have no side effects but macro definitions.
Especially, any call to AC_PREREQ should be done inside the
defined macro, not at the beginning of the file.
Starting with Automake 1.8, aclocal will warn about all
underquoted calls to AC_DEFUN. We realize this will annoy a
lot of people, because aclocal was not so strict in the past
and many third party macros are underquoted; and we have to apologize
for this temporary inconvenience. The reason we have to be stricter
is that a future implementation of aclocal (see Future of aclocal) will have to temporary include all these third party
.m4 files, maybe several times, even those which are not
actually needed. Doing so should alleviate many problem of the
current implementation, however it requires a stricter style from the
macro authors. Hopefully it is easy to revise the existing macros.
For instance
# bad style
AC_PREREQ(2.57)
AC_DEFUN(AX_FOOBAR,
[AC_REQUIRE([AX_SOMETHING])dnl
AX_FOO
AX_BAR
])
should be rewritten as
AC_DEFUN([AX_FOOBAR],
[AC_PREREQ(2.57)dnl
AC_REQUIRE([AX_SOMETHING])dnl
AX_FOO
AX_BAR
])
Wrapping the AC_PREREQ call inside the macro ensures that
Autoconf 2.57 will not be required if AX_FOOBAR is not actually
used. Most importantly, quoting the first argument of AC_DEFUN
allows the macro to be redefined or included twice (otherwise this
first argument would be expansed during the second definition).
If you have been directed here by the aclocal diagnostic but are not the maintainer of the implicated macro, you will want to contact the maintainer of that macro. Please make sure you have the last version of the macro and that the problem already hasn't been reported before doing so: people tend to work faster when they aren't flooded by mails.
Another situation where aclocal is commonly used is to manage macros which are used locally by the package, Local Macros.
Feature tests offered by Autoconf do not cover all needs. People often have to supplement existing tests with their own macros, or with third-party macros.
There are two ways to organize custom macros in a package.
The first possibility (the historical practice) is to list all your macros in acinclude.m4. This file will be included in aclocal.m4 when you run aclocal, and its macro(s) will henceforth be visible to autoconf. However if it contains numerous macros, it will rapidly become difficult to maintain, and it will be almost impossible to share macros between packages.
The second possibility, which we do recommend, is to write each macro
in its own file and gather all these files in a directory. This
directory is usually called m4/. To build aclocal.m4,
one should therefore instruct aclocal to scan m4/.
From the command line, this is done with aclocal -I m4. The
top-level Makefile.am should also be updated to define
ACLOCAL_AMFLAGS = -I m4
ACLOCAL_AMFLAGS contains options to pass to aclocal
when aclocal.m4 is to be rebuilt by make. This line is
also used by autoreconf (see Using autoreconf to Update configure Scripts (The Autoconf Manual)) to run aclocal with suitable
options, or by autopoint (see Invoking the autopoint Program (GNU gettext tools))
and gettextize (see Invoking the gettextize Program (GNU gettext tools)) to locate
the place where Gettext's macros should be installed. So even if you
do not really care about the rebuild rules, you should define
ACLOCAL_AMFLAGS.
When aclocal -I m4 is run, it will build a aclocal.m4
that m4_includes any file from m4/ that defines a
required macro. Macros not found locally will still be searched in
system-wide directories, as explained in Macro search path.
Custom macros should be distributed for the same reason that
configure.ac is: so that other people have all the sources of
your package if they want to work on it. Actually, this distribution
happens automatically because all m4_included files are
distributed.
However there is no consensus on the distribution of third-party
macros that your package may use. Many libraries install their own
macro in the system-wide aclocal directory (see Extending aclocal). For instance Guile ships with a file called
guile.m4 that contains the macro GUILE_FLAGS which can
be used to define setup compiler and linker flags appropriate for
using Guile. Using GUILE_FLAGS in configure.ac will
cause aclocal to copy guile.m4 into
aclocal.m4, but as guile.m4 is not part of the project,
it will not be distributed. Technically, that means a user which
needs to rebuild aclocal.m4 will have to install Guile first.
This is probably OK, if Guile already is a requirement to build the
package. However, if Guile is only an optional feature, or if your
package might run on architectures where Guile cannot be installed,
this requirement will hinder development. An easy solution is to copy
such third-party macros in your local m4/ directory so they get
distributed.
aclocal is expected to disappear. This feature really should not be offered by Automake. Automake should focus on generating Makefiles; dealing with M4 macros really is Autoconf's job. That some people install Automake just to use aclocal, but do not use automake otherwise is an indication of how that feature is misplaced.
The new implementation will probably be done slightly differently. For instance it could enforce the m4/-style layout discussed in Local Macros, and take care of copying (or even updating) third-party macro into this directory.
We have no idea when and how this will happen. This has been discussed several times in the past, but someone still has to commit itself to that non-trivial task.
From the user point of view, aclocal's removal might turn out to be painful. There is a simple precaution that you may take to make that switch more seamless: never call aclocal yourself. Keep this guy under the exclusive control of autoreconf and Automake's rebuild rules. Hopefully you won't need to worry about things breaking, when aclocal disappears, because everything will have been taken care of. If otherwise you used to call aclocal directly yourself or from some script, you will quickly notice the change.
Many packages come with a script called bootstrap.sh or autogen.sh, that will just call aclocal, libtoolize, gettextize or autopoint, autoconf, autoheader, and automake in the right order. Actually this is precisely what autoreconf can do for you. If your package has such a bootstrap.sh or autogen.sh script, consider using autoreconf. That should simplify its logic a lot (less things to maintain, yum!), it's even likely you will not need the script anymore, and more to the point you will not call aclocal directly anymore.
In packages with subdirectories, the top level Makefile.am must
tell Automake which subdirectories are to be built. This is done via
the SUBDIRS variable.
The SUBDIRS variable holds a list of subdirectories in which
building of various sorts can occur. The rules for many targets
(e.g. all) in the generated Makefile will run commands
both locally and in all specified subdirectories. Note that the
directories listed in SUBDIRS are not required to contain
Makefile.ams; only Makefiles (after configuration).
This allows inclusion of libraries from packages which do not use
Automake (such as gettext).
In packages that use subdirectories, the top-level Makefile.am is often very short. For instance, here is the Makefile.am from the GNU Hello distribution:
EXTRA_DIST = BUGS ChangeLog.O README-alpha
SUBDIRS = doc intl po src tests
When Automake invokes make in a subdirectory, it uses the value
of the MAKE variable. It passes the value of the variable
AM_MAKEFLAGS to the make invocation; this can be set in
Makefile.am if there are flags you must always pass to
make.
The directories mentioned in SUBDIRS must be direct children of
the current directory. For instance, you cannot put src/subdir
into SUBDIRS. Instead you should put SUBDIRS = subdir
into src/Makefile.am. Automake can be used to construct packages
of arbitrary depth this way.
By default, Automake generates Makefiles which work depth-first
(postfix). However, it is possible to change this ordering.
You can do this by putting . into SUBDIRS. For
instance, putting . first will cause a prefix ordering
of directories. All clean rules are run in reverse
order of build rules.
It is possible to define the SUBDIRS variable conditionally if,
like in the case of GNU Inetutils, you want to only build a
subset of the entire package.
To illustrate how this works, let's assume we have two directories
src/ and opt/. src/ should always be built, but we
want to decide in ./configure whether opt/ will be built
or not. (For this example we will assume that opt/ should be
built when the variable $want_opt was set to yes.)
Running make should thus recurse into src/ always, and
then maybe in opt/.
However make dist should always recurse into both src/ and
opt/. Because opt/ should be distributed even if it is
not needed in the current configuration. This means opt/Makefile
should be created unconditionally. 3
There are two ways to setup a project like this. You can use Automake
conditionals (see Conditionals) or use Autoconf AC_SUBST
variables (see Setting Output Variables (The Autoconf Manual)). Using Automake conditionals is the
preferred solution.
AM_CONDITIONALconfigure should output the Makefile for each directory and define a condition into which opt/ should be built.
...
AM_CONDITIONAL([COND_OPT], [test "$want_opt" = yes])
AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
...
Then SUBDIRS can be defined in the top-level Makefile.am
as follows.
if COND_OPT
MAYBE_OPT = opt
endif
SUBDIRS = src $(MAYBE_OPT)
As you can see, running make will rightly recurse into
src/ and maybe opt/.
As you can't see, running make dist will recurse into both
src/ and opt/ directories because make dist, unlike
make all, doesn't use the SUBDIRS variable. It uses the
DIST_SUBDIRS variable.
In this case Automake will define DIST_SUBDIRS = src opt
automatically because it knows that MAYBE_OPT can contain
opt in some condition.
AC_SUBSTAnother idea is to define MAYBE_OPT from ./configure using
AC_SUBST:
...
if test "$want_opt" = yes; then
MAYBE_OPT=opt
else
MAYBE_OPT=
fi
AC_SUBST([MAYBE_OPT])
AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
...
In this case the top-level Makefile.am should look as follows.
SUBDIRS = src $(MAYBE_OPT)
DIST_SUBDIRS = src opt
The drawback is that since Automake cannot guess what the possible
values of MAYBE_OPT are, it is necessary to define
DIST_SUBDIRS.
DIST_SUBDIRS is used
As shown in the above examples, DIST_SUBDIRS is used in rules
that need to recurse in all directories, even those which have been
conditionally left out of the build.
Precisely, DIST_SUBDIRS is used by make dist, make
distclean, and make maintainer-clean. All other recursive
rules use SUBDIRS.
Automake will define DIST_SUBDIRS automatically from the
possibles values of SUBDIRS in all conditions.
If SUBDIRS contains AC_SUBST variables,
DIST_SUBDIRS will not be defined correctly because Automake
doesn't know the possible values of these variables. In this case
DIST_SUBDIRS needs to be defined manually.
If you've ever read Peter Miller's excellent paper,
Recursive Make Considered Harmful, the preceding section on the use of
subdirectories will probably come as unwelcome advice. For those who
haven't read the paper, Miller's main thesis is that recursive
make invocations are both slow and error-prone.
Automake provides sufficient cross-directory support 4 to enable you to write a single Makefile.am for a complex multi-directory package.
By default an installable file specified in a subdirectory will have its directory name stripped before installation. For instance, in this example, the header file will be installed as $(includedir)/stdio.h:
include_HEADERS = inc/stdio.h
However, the nobase_ prefix can be used to circumvent this path stripping. In this example, the header file will be installed as $(includedir)/sys/types.h:
nobase_include_HEADERS = sys/types.h
nobase_ should be specified first when used in conjunction with either dist_ or nodist_ (see Dist). For instance:
nobase_dist_pkgdata_DATA = images/vortex.pgm
A large part of Automake's functionality is dedicated to making it easy to build programs and libraries.
In order to build a program, you need to tell Automake which sources are part of it, and which libraries it should be linked with.
This section also covers conditional compilation of sources or programs. Most of the comments about these also apply to libraries (see A Library) and libtool libraries (see A Shared Library).
In a directory containing source that gets built into a program (as
opposed to a library or a script), the PROGRAMS primary is used.
Programs can be installed in bindir, sbindir,
libexecdir, pkglibdir, or not at all (noinst).
They can also be built only for make check, in which case the
prefix is check.
For instance:
bin_PROGRAMS = hello
In this simple case, the resulting Makefile.in will contain code
to generate a program named hello.
Associated with each program are several assisting variables which are named after the program. These variables are all optional, and have reasonable defaults. Each variable, its use, and default is spelled out below; we use the “hello” example throughout.
The variable hello_SOURCES is used to specify which source files
get built into an executable:
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h
This causes each mentioned .c file to be compiled into the corresponding .o. Then all are linked to produce hello.
If hello_SOURCES is not specified, then it defaults to the single file hello.c (see Default _SOURCES). Multiple programs can be built in a single directory. Multiple programs can share a single source file, which must be listed in each _SOURCES definition.
Header files listed in a _SOURCES definition will be included in the distribution but otherwise ignored. In case it isn't obvious, you should not include the header file generated by configure in a _SOURCES variable; this file should not be distributed. Lex (.l) and Yacc (.y) files can also be listed; see Yacc and Lex.
If you need to link against libraries that are not found by
configure, you can use LDADD to do so. This variable is
used to specify additional objects or libraries to link with; it is
inappropriate for specifying specific linker flags, you should use
AM_LDFLAGS for this purpose.
Sometimes, multiple programs are built in one directory but do not share
the same link-time requirements. In this case, you can use the
prog_LDADD variable (where prog is the name of the
program as it appears in some _PROGRAMS variable, and usually
written in lowercase) to override the global LDADD. If this
variable exists for a given program, then that program is not linked
using LDADD.
For instance, in GNU cpio, pax, cpio and mt are
linked against the library libcpio.a. However, rmt is
built in the same directory, and has no such link requirement. Also,
mt and rmt are only built on certain architectures. Here
is what cpio's src/Makefile.am looks like (abridged):
bin_PROGRAMS = cpio pax $(MT)
libexec_PROGRAMS = $(RMT)
EXTRA_PROGRAMS = mt rmt
LDADD = ../lib/libcpio.a $(INTLLIBS)
rmt_LDADD =
cpio_SOURCES = ...
pax_SOURCES = ...
mt_SOURCES = ...
rmt_SOURCES = ...
prog_LDADD is inappropriate for passing program-specific linker flags (except for -l, -L, -dlopen and -dlpreopen). So, use the prog_LDFLAGS variable for this purpose. It is also occasionally useful to have a program depend on some other target which is not actually part of that program. This can be done using the prog_DEPENDENCIES variable. Each program depends on the contents of such a variable, but no further interpretation is done.
If prog_DEPENDENCIES is not supplied, it is computed by Automake. The automatically-assigned value is the contents of prog_LDADD, with most configure substitutions, -l, -L, -dlopen and -dlpreopen options removed. The configure substitutions that are left in are only $(LIBOBJS) and $(ALLOCA); these are left because it is known that they will not cause an invalid value for prog_DEPENDENCIES to be generated.
You can't put a configure substitution (e.g., @FOO@ or
$(FOO) where FOO is defined via AC_SUBST) into a
_SOURCES variable. The reason for this is a bit hard to
explain, but suffice to say that it simply won't work. Automake will
give an error if you try to do this.
Fortunately there are two other ways to achieve the same result. One is
to use configure substitutions in _LDADD variables, the other is
to use an Automake conditional.
_LDADD substitutions
Automake must know all the source files that could possibly go into a
program, even if not all the files are built in every circumstance. Any
files which are only conditionally built should be listed in the
appropriate EXTRA_ variable. For instance, if
hello-linux.c or hello-generic.c were conditionally included
in hello, the Makefile.am would contain:
bin_PROGRAMS = hello
hello_SOURCES = hello-common.c
EXTRA_hello_SOURCES = hello-linux.c hello-generic.c
hello_LDADD = $(HELLO_SYSTEM)
hello_DEPENDENCIES = $(HELLO_SYSTEM)
You can then setup the $(HELLO_SYSTEM) substitution from
configure.ac:
...
case $host in
*linux*) HELLO_SYSTEM='hello-linux.$(OBJEXT)' ;;
*) HELLO_SYSTEM='hello-generic.$(OBJEXT)' ;;
esac
AC_SUBST([HELLO_SYSTEM])
...
In this case, HELLO_SYSTEM should be replaced by
hello-linux.o or hello-generic.o, and added to
hello_DEPENDENCIES and hello_LDADD in order to be built
and linked in.
An often simpler way to compile source files conditionally is to use Automake conditionals. For instance, you could use this Makefile.am construct to build the same hello example:
bin_PROGRAMS = hello
if LINUX
hello_SOURCES = hello-linux.c hello-common.c
else
hello_SOURCES = hello-generic.c hello-common.c
endif
In this case, your configure.ac should setup the LINUX
conditional using AM_CONDITIONAL (see Conditionals).
When using conditionals like this you don't need to use the EXTRA_ variable, because Automake will examine the contents of each variable to construct the complete list of source files.
If your program uses a lot of files, you will probably prefer a
conditional +=.
bin_PROGRAMS = hello
hello_SOURCES = hello-common.c
if LINUX
hello_SOURCES += hello-linux.c
else
hello_SOURCES += hello-generic.c
endif
Sometimes it is useful to determine the programs that are to be built
at configure time. For instance, GNU cpio only builds
mt and rmt under special circumstances. The means to
achieve conditional compilation of programs are the same you can use
to compile source files conditionally: substitutions or conditionals.
configure substitutionsIn this case, you must notify Automake of all the programs that can
possibly be built, but at the same time cause the generated
Makefile.in to use the programs specified by configure.
This is done by having configure substitute values into each
_PROGRAMS definition, while listing all optionally built programs
in EXTRA_PROGRAMS.
bin_PROGRAMS = cpio pax $(MT)
libexec_PROGRAMS = $(RMT)
EXTRA_PROGRAMS = mt rmt
As explained in EXEEXT, Automake will rewrite
bin_PROGRAMS, libexec_PROGRAMS, and
EXTRA_PROGRAMS, appending $(EXEEXT) to each binary.
Obviously it cannot rewrite values obtained at run-time through
configure substitutions, therefore you should take care of
appending $(EXEEXT) yourself, as in AC_SUBST([MT],
['mt${EXEEXT}']).
You can also use Automake conditionals (see Conditionals) to
select programs to be built. In this case you don't have to worry
about $(EXEEXT) or EXTRA_PROGRAMS.
bin_PROGRAMS = cpio pax
if WANT_MT
bin_PROGRAMS += mt
endif
if WANT_RMT
libexec_PROGRAMS = rmt
endif
Building a library is much like building a program. In this case, the
name of the primary is LIBRARIES. Libraries can be installed in
libdir or pkglibdir.
See A Shared Library, for information on how to build shared libraries using libtool and the LTLIBRARIES primary.
Each _LIBRARIES variable is a list of the libraries to be built. For instance to create a library named libcpio.a, but not install it, you would write:
noinst_LIBRARIES = libcpio.a
The sources that go into a library are determined exactly as they are for programs, via the _SOURCES variables. Note that the library name is canonicalized (see Canonicalization), so the _SOURCES variable corresponding to liblob.a is liblob_a_SOURCES, not liblob.a_SOURCES.
Extra objects can be added to a library using the
library_LIBADD variable. This should be used for objects
determined by configure. Again from cpio:
libcpio_a_LIBADD = $(LIBOBJS) $(ALLOCA)
In addition, sources for extra objects that will not exist until
configure-time must be added to the BUILT_SOURCES variable
(see Sources).
Building a static library is done by compiling all object files, then
by invoking $(AR) $(ARFLAGS) followed by the name of the
library and the list of objects, and finally by calling
$(RANLIB) on that library. You should call
AC_PROG_RANLIB from your configure.ac to define
RANLIB (Automake will complain otherwise). AR and
ARFLAGS default to ar and cru respectively; you
can override these two variables my setting them in your
Makefile.am, by AC_SUBSTing them from your
configure.ac, or by defining a per-library maude_AR
variable (see Program and Library Variables).
Building shared libraries portably is a relatively complex matter. For this reason, GNU Libtool (see Introduction (The Libtool Manual)) was created to help build shared libraries in a platform-independent way.
Libtool abstracts shared and static libraries into a unified
concept henceforth called libtool libraries. Libtool libraries
are files using the .la suffix, and can designate a static
library, a shared library, or maybe both. Their exact nature cannot
be determined until ./configure is run: not all platforms
support all kinds of libraries, and users can explicitly select which
libraries should be built. (However the package's maintainers can
tune the default, See The AC_PROG_LIBTOOL macro (The Libtool Manual).)
Because object files for shared and static libraries must be compiled differently, libtool is also used during compilation. Object files built by libtool are called libtool objects: these are files using the .lo suffix. Libtool libraries are built from these libtool objects.
You should not assume anything about the structure of .la or .lo files and how libtool constructs them: this is libtool's concern, and the last thing one wants is to learn about libtool's guts. However the existence of these files matters, because they are used as targets and dependencies in Makefiles rules when building libtool libraries. There are situations where you may have to refer to these, for instance when expressing dependencies for building source files conditionally (see Conditional Libtool Sources).
People considering writing a plug-in system, with dynamically loaded modules, should look into libltdl: libtool's dlopening library (see Using libltdl (The Libtool Manual)). This offers a portable dlopening facility to load libtool libraries dynamically, and can also achieve static linking where unavoidable.
Before we discuss how to use libtool with Automake in details, it should be noted that the libtool manual also has a section about how to use Automake with libtool (see Using Automake with Libtool (The Libtool Manual)).
Automake uses libtool to build libraries declared with the LTLIBRARIES primary. Each _LTLIBRARIES variable is a list of libtool libraries to build. For instance, to create a libtool library named libgettext.la, and install it in libdir, write:
lib_LTLIBRARIES = libgettext.la
libgettext_la_SOURCES = gettext.c gettext.h ...
Automake predefines the variable pkglibdir, so you can use
pkglib_LTLIBRARIES to install libraries in
$(libdir)/@PACKAGE@/.
Like conditional programs (see Conditional Programs), there are
two main ways to build conditional libraries: using Automake
conditionals or using Autoconf AC_SUBSTitutions.
The important implementation detail you have to be aware of is that
the place where a library will be installed matters to libtool: it
needs to be indicated at link-time using the -rpath
option.
For libraries whose destination directory is known when Automake runs,
Automake will automatically supply the appropriate -rpath
option to libtool. This is the case for libraries listed explicitly in
some installable _LTLIBRARIES variables such as
lib_LTLIBRARIES.
However, for libraries determined at configure time (and thus
mentioned in EXTRA_LTLIBRARIES), Automake does not know the
final installation directory. For such libraries you must add the
-rpath option to the appropriate _LDFLAGS variable by
hand.
The examples below illustrate the differences between these two methods.
Here is an example where $(WANTEDLIBS) is an AC_SUBSTed
variable set at ./configure-time to either libfoo.la,
libbar.la, both, or none. Although $(WANTEDLIBS)
appears in the lib_LTLIBRARIES, Automake cannot guess it
relates to libfoo.la or libbar.la by the time it creates
the link rule for these two libraries. Therefore the -rpath
argument must be explicitly supplied.
EXTRA_LTLIBRARIES = libfoo.la libbar.la
lib_LTLIBRARIES = $(WANTEDLIBS)
libfoo_la_SOURCES = foo.c ...
libfoo_la_LDFLAGS = -rpath '$(libdir)'
libbar_la_SOURCES = bar.c ...
libbar_la_LDFLAGS = -rpath '$(libdir)'
Here is how the same Makefile.am would look using Automake
conditionals named WANT_LIBFOO and WANT_LIBBAR. Now
Automake is able to compute the -rpath setting itself, because
it's clear that both libraries will end up in $(libdir) if they
are installed.
lib_LTLIBRARIES =
if WANT_LIBFOO
lib_LTLIBRARIES += libfoo.la
endif
if WANT_LIBBAR
lib_LTLIBRARIES += libbar.la
endif
libfoo_la_SOURCES = foo.c ...
libbar_la_SOURCES = bar.c ...
Conditional compilation of sources in a library can be achieved in the
same way as conditional compilation of sources in a program
(see Conditional Sources). The only difference is that
_LIBADD should be used instead of _LDADD and that it
should mention libtool objects (.lo files).
So, to mimic the hello example from Conditional Sources, we could build a libhello.la library using either hello-linux.c or hello-generic.c with the following Makefile.am.
lib_LTLIBRARIES = libhello.la
libhello_la_SOURCES = hello-common.c
EXTRA_libhello_la_SOURCES = hello-linux.c hello-generic.c
libhello_la_LIBADD = $(HELLO_SYSTEM)
libhello_la_DEPENDENCIES = $(HELLO_SYSTEM)
And make sure $(HELLO_SYSTEM) is set to either
hello-linux.lo or hello-generic.lo in
./configure.
Or we could simply use an Automake conditional as follows.
lib_LTLIBRARIES = libhello.la
libhello_la_SOURCES = hello-common.c
if LINUX
libhello_la_SOURCES += hello-linux.c
else
libhello_la_SOURCES += hello-generic.c
endif
Sometimes you want to build libtool libraries which should not be installed. These are called libtool convenience libraries and are typically used to encapsulate many sublibraries, later gathered into one big installed library.
Libtool convenience libraries are declared by
noinst_LTLIBRARIES, check_LTLIBRARIES, or even
EXTRA_LTLIBRARIES. Unlike installed libtool libraries they do
not need an -rpath flag at link time (actually this is the only
difference).
Convenience libraries listed in noinst_LTLIBRARIES are always
built. Those listed in check_LTLIBRARIES are built only upon
make check. Finally, libraries listed in
EXTRA_LTLIBRARIES are never built explicitly: Automake outputs
rules to build them, but if the library does not appear as a Makefile
dependency anywhere it won't be built (this is why
EXTRA_LTLIBRARIES is used for conditional compilation).
Here is a sample setup merging libtool convenience libraries from subdirectories into one main libtop.la library.
# -- Top-level Makefile.am --
SUBDIRS = sub1 sub2 ...
lib_LTLIBRARIES = libtop.la
libtop_la_SOURCES =
libtop_la_LIBADD = \
sub1/libsub1.la \
sub2/libsub2.la \
...
# -- sub1/Makefile.am --
noinst_LTLIBRARIES = libsub1.la
libsub1_la_SOURCES = ...
# -- sub2/Makefile.am --
# showing nested convenience libraries
SUBDIRS = sub2.1 sub2.2 ...
noinst_LTLIBRARIES = libsub2.la
libsub2_la_SOURCES =
libsub2_la_LIBADD = \
sub21/libsub21.la \
sub22/libsub22.la \
...
These are libtool libraries meant to be dlopened. They are
indicated to libtool by passing -module at link-time.
pkglib_LTLIBRARIES = mymodule.la
mymodule_la_SOURCES = doit.c
mymodule_LDFLAGS = -module
Ordinarily, Automake requires that a Library's name starts with lib. However, when building a dynamically loadable module you might wish to use a "nonstandard" name.
If mymodule_la_SOURCES is not specified, then it defaults to the single file mymodule.c (see Default _SOURCES).
As shown in previous sections, the library_LIBADD variable should be used to list extra libtool objects (.lo files) or libtool libraries (.la) to add to library.
The library_LDFLAGS variable is the place to list additional libtool flags, such as -version-info, -static, and a lot more. See See Using libltdl (The Libtool Manual).
LTLIBOBJS
Where an ordinary library might include $(LIBOBJS), a libtool
library must use $(LTLIBOBJS). This is required because the
object files that libtool operates on do not necessarily end in
.o.
Nowadays, the computation of LTLIBOBJS from LIBOBJS is
performed automatically by Autoconf (see AC_LIBOBJ vs. LIBOBJS (The Autoconf Manual)).
required file `./ltmain.sh' not foundLibtool comes with a tool called libtoolize that will install libtool's supporting files into a package. Running this command will install ltmain.sh. You should execute it before aclocal and automake.
People upgrading old packages to newer autotools are likely to face this issue because older Automake versions used to call libtoolize. Therefore old build scripts do not call libtoolize.
Since Automake 1.6, it has been decided that running libtoolize was none of Automake's business. Instead, that functionality has been moved into the autoreconf command (see Using autoreconf (The Autoconf Manual)). If you do not want to remember what to run and when, just learn the autoreconf command. Hopefully, replacing existing bootstrap.sh or autogen.sh scripts by a call to autoreconf should also free you from any similar incompatible change in the future.
created with both libtool and withoutSometimes, the same source file is used both to build a libtool library and to build another non-libtool target (be it a program or another library).
Let's consider the following Makefile.am.
bin_PROGRAMS = prog
prog_SOURCES = prog.c foo.c ...
lib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = foo.c ...
(In this trivial case the issue could be avoided by linking
libfoo.la with prog instead of listing foo.c in
prog_SOURCES. But let's assume we really want to keep
prog and libfoo.la separate.)
Technically, it means that we should build foo.$(OBJEXT) for prog, and foo.lo for libfoo.la. The problem is that in the course of creating foo.lo, libtool may erase (or replace) foo.$(OBJEXT) – and this cannot be avoided.
Therefore, when Automake detects this situation it will complain with a message such as
object `foo.$(OBJEXT)' created both with libtool and without
A workaround for this issue is to ensure that these two objects get different basenames. As explained in renamed objects, this happens automatically when per-targets flags are used.
bin_PROGRAMS = prog
prog_SOURCES = prog.c foo.c ...
prog_CFLAGS = $(AM_CFLAGS)
lib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = foo.c ...
Adding prog_CFLAGS = $(AM_CFLAGS) is almost a no-op, because
when the prog_CFLAGS is defined, it is used instead of
AM_CFLAGS. However as a side effect it will cause
prog.c and foo.c to be compiled as
prog-prog.$(OBJEXT) and prog-foo.$(OBJEXT) which solves
the issue.
Associated with each program are a collection of variables which can be used to modify how that program is built. There is a similar list of such variables for each library. The canonical name of the program (or library) is used as a base for naming these variables.
In the list below, we use the name “maude” to refer to the program or library. In your Makefile.am you would replace this with the canonical name of your program. This list also refers to “maude” as a program, but in general the same rules apply for both static and dynamic libraries; the documentation below notes situations where programs and libraries differ.
The prefixes dist_ and nodist_ can be used to control whether files listed in a _SOURCES variable are distributed. dist_ is redundant, as sources are distributed by default, but it can be specified for clarity if desired.
It is possible to have both dist_ and nodist_ variants of a given _SOURCES variable at once; this lets you easily distribute some files and not others, for instance:
nodist_maude_SOURCES = nodist.c
dist_maude_SOURCES = dist-me.c
By default the output file (on Unix systems, the .o file) will be
put into the current build directory. However, if the option
subdir-objects is in effect in the current directory then the
.o file will be put into the subdirectory named after the source
file. For instance, with subdir-objects enabled,
sub/dir/file.c will be compiled to sub/dir/file.o. Some
people prefer this mode of operation. You can specify
subdir-objects in AUTOMAKE_OPTIONS (see Options).
This variable also supports dist_ and nodist_ prefixes,
e.g., nodist_EXTRA_maude_SOURCES.
$(AR)
$(ARFLAGS) followed by the name of the library and then the objects
being put into the library. You can override this by setting the
_AR variable. This is usually used with C++; some C++
compilers require a special invocation in order to instantiate all the
templates which should go into a library. For instance, the SGI C++
compiler likes this variable set like so:
libmaude_a_AR = $(CXX) -ar -o
configure (see A Library).
configure (see Linking).
_LDADD and _LIBADD are inappropriate for passing program-specific linker flags (except for -l, -L, -dlopen and -dlpreopen). Use the _LDFLAGS variable for this purpose.
For instance, if your configure.ac uses AC_PATH_XTRA, you
could link your program against the X libraries like so:
maude_LDADD = $(X_PRE_LIBS) $(X_LIBS) $(X_EXTRA_LIBS)
If _DEPENDENCIES is not supplied, it is computed by Automake.
The automatically-assigned value is the contents of _LDADD or
_LIBADD, with most configure substitutions, -l, -L,
-dlopen and -dlpreopen options removed. The configure
substitutions that are left in are only $(LIBOBJS) and
$(ALLOCA); these are left because it is known that they will not
cause an invalid value for _DEPENDENCIES to be generated.
maude_LINK = $(CCLD) -magic -o $@
When using a per-target compilation flag, Automake will choose a different name for the intermediate object files. Ordinarily a file like sample.c will be compiled to produce sample.o. However, if the program's _CFLAGS variable is set, then the object file will be named, for instance, maude-sample.o. (See also renamed objects.)
In compilations with per-target flags, the ordinary AM_ form of the flags variable is not automatically included in the compilation (however, the user form of the variable is included). So for instance, if you want the hypothetical maude compilations to also use the value of AM_CFLAGS, you would need to write:
maude_CFLAGS = ... your flags ... $(AM_CFLAGS)
bin_PROGRAMS = maude
maude_CPPFLAGS = -DSOMEFLAG
maude_SHORTNAME = m
maude_SOURCES = sample.c ...
the object file would be named m-sample.o rather than maude-sample.o.
This facility is rarely needed in practice, and we recommend avoiding it until you find it is required.
_SOURCES
_SOURCES variables are used to specify source files of programs
(see A Program), libraries (see A Library), and Libtool
libraries (see A Shared Library).
When no such variable is specified for a target, Automake will define one itself. The default is to compile a single C file whose base name is the name of the target itself, with any extension replaced by .c. (Defaulting to C is terrible but we are stuck with it for historical reasons.)
For example if you have the following somewhere in your Makefile.am with no corresponding libfoo_a_SOURCES:
lib_LIBRARIES = libfoo.a sub/libc++.a
libfoo.a will be built using a default source file named libfoo.c, and sub/libc++.a will be built from sub/libc++.c. (In older versions sub/libc++.a would be built from sub_libc___a.c, i.e., the default source was the canonized name of the target, with .c appended. Be believe the new behavior is more sensible, but for backward compatibility automake will use the old name if a file or a rule with that name exist.)
Default sources are mainly useful in test suites, when building many tests programs each from a single source. For instance in
check_PROGRAMS = test1 test2 test3
test1, test2, and test3 will be built from test1.c, test2.c, and test3.c.
Another case where is this convenient is building many Libtool modules (moduleN.la), each defined in its own file (moduleN.c).
AM_LDFLAGS = -module
lib_LTLIBRARIES = module1.la module2.la module3.la
Finally, there is one situation where this default source computation
needs to be avoided: when a target should not be built from sources.
We already saw such an example in true; this happens when all
the constituents of a target have already been compiled and need just
to be combined using a _LDADD variable. Then it is necessary
to define an empty _SOURCES variable, so that automake does not
compute a default.
bin_PROGRAMS = target
target_SOURCES =
target_LDADD = libmain.a libmisc.a
Automake explicitly recognizes the use of $(LIBOBJS) and
$(ALLOCA), and uses this information, plus the list of
LIBOBJS files derived from configure.ac to automatically
include the appropriate source files in the distribution (see Dist).
These source files are also automatically handled in the
dependency-tracking scheme; see See Dependencies.
$(LIBOBJS) and $(ALLOCA) are specially recognized in any
_LDADD or _LIBADD variable.
Occasionally it is useful to know which Makefile variables Automake uses for compilations; for instance you might need to do your own compilation in some special cases.
Some variables are inherited from Autoconf; these are CC,
CFLAGS, CPPFLAGS, DEFS, LDFLAGS, and
LIBS.
There are some additional variables which Automake itself defines:
AM_CPPFLAGSAutomake already provides some -I options automatically. In
particular it generates -I$(srcdir), -I., and a -I
pointing to the directory holding config.h (if you've used
AC_CONFIG_HEADERS or AM_CONFIG_HEADER). You can disable
the default -I options using the nostdinc option.
AM_CPPFLAGS is ignored in preference to a per-executable (or
per-library) _CPPFLAGS variable if it is defined.
INCLUDESAM_CFLAGS_CFLAGS.
COMPILEAM_LDFLAGS_LDFLAGS.
LINKCFLAGS); it takes as “arguments” the names of the object files
and libraries to link in.
Automake has somewhat idiosyncratic support for Yacc and Lex.
Automake assumes that the .c file generated by yacc (or
lex) should be named using the basename of the input file. That
is, for a yacc source file foo.y, Automake will cause the
intermediate file to be named foo.c (as opposed to
y.tab.c, which is more traditional).
The extension of a yacc source file is used to determine the extension of the resulting C or C++ file. Files with the extension .y will be turned into .c files; likewise, .yy will become .cc; .y++, c++; and .yxx, .cxx.
Likewise, lex source files can be used to generate C or C++; the extensions .l, .ll, .l++, and .lxx are recognized.
You should never explicitly mention the intermediate (C or C++) file in any SOURCES variable; only list the source file.
The intermediate files generated by yacc (or lex) will be
included in any distribution that is made. That way the user doesn't
need to have yacc or lex.
If a yacc source file is seen, then your configure.ac must
define the variable YACC. This is most easily done by invoking
the macro AC_PROG_YACC (see Particular Program Checks (The Autoconf Manual)).
When yacc is invoked, it is passed YFLAGS and
AM_YFLAGS. The former is a user variable and the latter is
intended for the Makefile.am author.
AM_YFLAGS is usually used to pass the -d option to
yacc. Automake knows what this means and will automatically
adjust its rules to update and distribute the header file built by
yacc -d. What Automake cannot guess, though, is where this
header will be used: it is up to you to ensure the header gets built
before it is first used. Typically this is necessary in order for
dependency tracking to work when the header is included by another
file. The common solution is listing the header file in
BUILT_SOURCES (see Sources) as follows.
BUILT_SOURCES = parser.h
AM_YFLAGS = -d
bin_PROGRAMS = foo
foo_SOURCES = ... parser.y ...
If a lex source file is seen, then your configure.ac
must define the variable LEX. You can use AC_PROG_LEX
to do this (see Particular Program Checks (The Autoconf Manual)), but using AM_PROG_LEX macro
(see Macros) is recommended.
When lex is invoked, it is passed LFLAGS and
AM_LFLAGS. The former is a user variable and the latter is
intended for the Makefile.am author.
Automake makes it possible to include multiple yacc (or
lex) source files in a single program. When there is more than
one distinct yacc (or lex) source file in a directory,
Automake uses a small program called ylwrap to run yacc
(or lex) in a subdirectory. This is necessary because yacc's
output filename is fixed, and a parallel make could conceivably invoke
more than one instance of yacc simultaneously. The ylwrap
program is distributed with Automake. It should appear in the directory
specified by AC_CONFIG_AUX_DIR (see Finding `configure' Input (The Autoconf Manual)), or the current
directory if that macro is not used in configure.ac.
For yacc, simply managing locking is insufficient. The output of
yacc always uses the same symbol names internally, so it isn't
possible to link two yacc parsers into the same executable.
We recommend using the following renaming hack used in gdb:
#define yymaxdepth c_maxdepth
#define yyparse c_parse
#define yylex c_lex
#define yyerror c_error
#define yylval c_lval
#define yychar c_char
#define yydebug c_debug
#define yypact c_pact
#define yyr1 c_r1
#define yyr2 c_r2
#define yydef c_def
#define yychk c_chk
#define yypgo c_pgo
#define yyact c_act
#define yyexca c_exca
#define yyerrflag c_errflag
#define yynerrs c_nerrs
#define yyps c_ps
#define yypv c_pv
#define yys c_s
#define yy_yys c_yys
#define yystate c_state
#define yytmp c_tmp
#define yyv c_v
#define yy_yyv c_yyv
#define yyval c_val
#define yylloc c_lloc
#define yyreds c_reds
#define yytoks c_toks
#define yylhs c_yylhs
#define yylen c_yylen
#define yydefred c_yydefred
#define yydgoto c_yydgoto
#define yysindex c_yysindex
#define yyrindex c_yyrindex
#define yygindex c_yygindex
#define yytable c_yytable
#define yycheck c_yycheck
#define yyname c_yyname
#define yyrule c_yyrule
For each define, replace the c_ prefix with whatever you like.
These defines work for bison, byacc, and traditional
yaccs. If you find a parser generator that uses a symbol not
covered here, please report the new name so it can be added to the list.
Automake includes full support for C++.
Any package including C++ code must define the output variable
CXX in configure.ac; the simplest way to do this is to use
the AC_PROG_CXX macro (see Particular Program Checks (The Autoconf Manual)).
A few additional variables are defined when a C++ source file is seen:
CXXCXXFLAGSAM_CXXFLAGSCXXFLAGS.
CXXCOMPILECXXLINKAutomake includes some support for assembly code.
The variable CCAS holds the name of the compiler used to build
assembly code. This compiler must work a bit like a C compiler; in
particular it must accept -c and -o. The value of
CCASFLAGS is passed to the compilation.
You are required to set CCAS and CCASFLAGS via
configure.ac. The autoconf macro AM_PROG_AS will do this
for you. Unless they are already set, it simply sets CCAS to the
C compiler and CCASFLAGS to the C compiler flags.
Only the suffixes .s and .S are recognized by
automake as being files containing assembly code.
Automake includes full support for Fortran 77.
Any package including Fortran 77 code must define the output variable
F77 in configure.ac; the simplest way to do this is to use
the AC_PROG_F77 macro (see Particular Program Checks (The Autoconf Manual)).
A few additional variables are defined when a Fortran 77 source file is seen:
F77FFLAGSAM_FFLAGSFFLAGS.
RFLAGSAM_RFLAGSRFLAGS.
F77COMPILEFLINKAutomake can handle preprocessing Fortran 77 and Ratfor source files in addition to compiling them6. Automake also contains some support for creating programs and shared libraries that are a mixture of Fortran 77 and other languages (see Mixing Fortran 77 With C and C++).
These issues are covered in the following sections.
N.f is made automatically from N.F or N.r. This rule runs just the preprocessor to convert a preprocessable Fortran 77 or Ratfor source file into a strict Fortran 77 source file. The precise command used is as follows:
$(F77) -F $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_FFLAGS) $(FFLAGS)
$(F77) -F $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)
N.o is made automatically from N.f, N.F or N.r by running the Fortran 77 compiler. The precise command used is as follows:
$(F77) -c $(AM_FFLAGS) $(FFLAGS)
$(F77) -c $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_FFLAGS) $(FFLAGS)
$(F77) -c $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)
Automake currently provides limited support for creating programs and shared libraries that are a mixture of Fortran 77 and C and/or C++. However, there are many other issues related to mixing Fortran 77 with other languages that are not (currently) handled by Automake, but that are handled by other packages7.
Automake can help in two ways:
These extra Fortran 77 linker flags are supplied in the output variable
FLIBS by the AC_F77_LIBRARY_LDFLAGS Autoconf macro
supplied with newer versions of Autoconf (Autoconf version 2.13 and
later). See Fortran 77 Compiler Characteristics (The Autoconf).
If Automake detects that a program or shared library (as mentioned in
some _PROGRAMS or _LTLIBRARIES primary) contains source
code that is a mixture of Fortran 77 and C and/or C++, then it requires
that the macro AC_F77_LIBRARY_LDFLAGS be called in
configure.ac, and that either $(FLIBS)
appear in the appropriate _LDADD (for programs) or _LIBADD
(for shared libraries) variables. It is the responsibility of the
person writing the Makefile.am to make sure that $(FLIBS)
appears in the appropriate _LDADD or
_LIBADD variable.
For example, consider the following Makefile.am:
bin_PROGRAMS = foo
foo_SOURCES = main.cc foo.f
foo_LDADD = libfoo.la $(FLIBS)
pkglib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES = bar.f baz.c zardoz.cc
libfoo_la_LIBADD = $(FLIBS)
In this case, Automake will insist that AC_F77_LIBRARY_LDFLAGS
is mentioned in configure.ac. Also, if $(FLIBS) hadn't
been mentioned in foo_LDADD and libfoo_la_LIBADD, then
Automake would have issued a warning.
The following diagram demonstrates under what conditions a particular linker is chosen by Automake.
For example, if Fortran 77, C and C++ source code were to be compiled
into a program, then the C++ linker will be used. In this case, if the
C or Fortran 77 linkers required any special libraries that weren't
included by the C++ linker, then they must be manually added to an
_LDADD or _LIBADD variable by the user writing the
Makefile.am.
\ Linker
source \
code \ C C++ Fortran
----------------- +---------+---------+---------+
| | | |
C | x | | |
| | | |
+---------+---------+---------+
| | | |
C++ | | x | |
| | | |
+---------+---------+---------+
| | | |
Fortran | | | x |
| | | |
+---------+---------+---------+
| | | |
C + C++ | | x | |
| | | |
+---------+---------+---------+
| | | |
C + Fortran | | | x |
| | | |
+---------+---------+---------+
| | | |
C++ + Fortran | | x | |
| | | |
+---------+---------+---------+
| | | |
C + C++ + Fortran | | x | |
| | | |
+---------+---------+---------+
Automake includes support for compiled Java, using gcj, the Java
front end to the GNU Compiler Collection.
Any package including Java code to be compiled must define the output
variable GCJ in configure.ac; the variable GCJFLAGS
must also be defined somehow (either in configure.ac or
Makefile.am). The simplest way to do this is to use the
AM_PROG_GCJ macro.
By default, programs including Java source files are linked with
gcj.
As always, the contents of AM_GCJFLAGS are passed to every
compilation invoking gcj (in its role as an ahead-of-time
compiler – when invoking it to create .class files,
AM_JAVACFLAGS is used instead). If it is necessary to pass
options to gcj from Makefile.am, this variable, and not
the user variable GCJFLAGS, should be used.
gcj can be used to compile .java, .class,
.zip, or .jar files.
When linking, gcj requires that the main class be specified
using the --main= option. The easiest way to do this is to use
the _LDFLAGS variable for the program.
Automake currently only includes full support for C, C++ (see C++ Support), Fortran 77 (see Fortran 77 Support), and Java (see Java Support). There is only rudimentary support for other languages, support for which will be improved based on user demand.
Some limited support for adding your own languages is available via the suffix rule handling; see Suffixes.
Although the GNU standards allow the use of ANSI C, this can have the effect of limiting portability of a package to some older compilers (notably the SunOS C compiler).
Automake allows you to work around this problem on such machines by de-ANSI-fying each source file before the actual compilation takes place.
If the Makefile.am variable AUTOMAKE_OPTIONS
(see Options) contains the option ansi2knr then code to
handle de-ANSI-fication is inserted into the generated
Makefile.in.
This causes each C source file in the directory to be treated as ANSI C.
If an ANSI C compiler is available, it is used. If no ANSI C compiler
is available, the ansi2knr program is used to convert the source
files into K&R C, which is then compiled.
The ansi2knr program is simple-minded. It assumes the source
code will be formatted in a particular way; see the ansi2knr man
page for details.
Support for de-ANSI-fication requires the source files ansi2knr.c
and ansi2knr.1 to be in the same package as the ANSI C source;
these files are distributed with Automake. Also, the package
configure.ac must call the macro AM_C_PROTOTYPES
(see Macros).
Automake also handles finding the ansi2knr support files in some
other directory in the current package. This is done by prepending the
relative path to the appropriate directory to the ansi2knr
option. For instance, suppose the package has ANSI C code in the
src and lib subdirectories. The files ansi2knr.c and
ansi2knr.1 appear in lib. Then this could appear in
src/Makefile.am:
AUTOMAKE_OPTIONS = ../lib/ansi2knr
If no directory prefix is given, the files are assumed to be in the current directory.
Note that automatic de-ANSI-fication will not work when the package is
being built for a different host architecture. That is because automake
currently has no way to build ansi2knr for the build machine.
Using LIBOBJS with source de-ANSI-fication used to require
hand-crafted code in configure to append $U to basenames
in LIBOBJS. This is no longer true today. Starting with version
2.54, Autoconf takes care of rewriting LIBOBJS and
LTLIBOBJS. (see AC_LIBOBJ vs. LIBOBJS (The Autoconf Manual))
As a developer it is often painful to continually update the Makefile.in whenever the include-file dependencies change in a project. Automake supplies a way to automatically track dependency changes.
Automake always uses complete dependencies for a compilation, including
system headers. Automake's model is that dependency computation should
be a side effect of the build. To this end, dependencies are computed
by running all compilations through a special wrapper program called
depcomp. depcomp understands how to coax many different C
and C++ compilers into generating dependency information in the format
it requires. automake -a will install depcomp into your
source tree for you. If depcomp can't figure out how to properly
invoke your compiler, dependency tracking will simply be disabled for
your build.
Experience with earlier versions of Automake 8 taught us that it is not reliable to generate dependencies only on the maintainer's system, as configurations vary too much. So instead Automake implements dependency tracking at build time.
Automatic dependency tracking can be suppressed by putting
no-dependencies in the variable AUTOMAKE_OPTIONS, or
passing no-dependencies as an argument to AM_INIT_AUTOMAKE
(this should be the preferred way). Or, you can invoke automake
with the -i option. Dependency tracking is enabled by default.
The person building your package also can choose to disable dependency
tracking by configuring with --disable-dependency-tracking.
On some platforms, such as Windows, executables are expected to have an extension such as .exe. On these platforms, some compilers (GCC among them) will automatically generate foo.exe when asked to generate foo.
Automake provides mostly-transparent support for this. Unfortunately mostly doesn't yet mean fully. Until the English dictionary is revised, you will have to assist Automake if your package must support those platforms.
One thing you must be aware of is that, internally, Automake rewrites something like this:
bin_PROGRAMS = liver
to this:
bin_PROGRAMS = liver$(EXEEXT)
The targets Automake generates are likewise given the $(EXEEXT)
extension. EXEEXT
However, Automake cannot apply this rewriting to configure
substitutions. This means that if you are conditionally building a
program using such a substitution, then your configure.ac must
take care to add $(EXEEXT) when constructing the output variable.
With Autoconf 2.13 and earlier, you must explicitly use AC_EXEEXT
to get this support. With Autoconf 2.50, AC_EXEEXT is run
automatically if you configure a compiler (say, through
AC_PROG_CC).
Sometimes maintainers like to write an explicit link rule for their program. Without executable extension support, this is easy—you simply write a rule whose target is the name of the program. However, when executable extension support is enabled, you must instead add the $(EXEEXT) suffix.
Unfortunately, due to the change in Autoconf 2.50, this means you must
always add this extension. However, this is a problem for maintainers
who know their package will never run on a platform that has
executable extensions. For those maintainers, the no-exeext
option (see Options) will disable this feature. This works in a
fairly ugly way; if no-exeext is seen, then the presence of a
rule for a target named foo in Makefile.am will override
an automake-generated rule for foo$(EXEEXT). Without
the no-exeext option, this use will give a diagnostic.
Automake can handle derived objects which are not C programs. Sometimes the support for actually building such objects must be explicitly supplied, but Automake will still automatically handle installation and distribution.
It is possible to define and install programs which are scripts. Such programs are listed using the SCRIPTS primary name. Automake doesn't define any dependencies for scripts; the Makefile.am should include the appropriate rules. Automake does not assume that scripts are derived objects; such objects must be deleted by hand (see Clean).
The automake program itself is a Perl script that is generated
from automake.in. Here is how this is handled:
bin_SCRIPTS = automake
CLEANFILES = $(bin_SCRIPTS)
do_subst = sed -e 's,[@]datadir[@],$(datadir),g' \
-e 's,[@]PERL[@],$(PERL),g' \
-e 's,[@]PACKAGE[@],$(PACKAGE),g' \
-e 's,[@]VERSION[@],$(VERSION),g' \
...
automake: automake.in Makefile
$(do_subst) < $(srcdir)/automake.in > automake
chmod +x automake
Because—as we have just seen—scripts can be built, they are not
distributed by default. Scripts that should be distributed can be
specified using a dist_ prefix as in other primaries. For
instance the following Makefile.am declares that
my_script should be distributed and installed in
$(sbindir).
dist_sbin_SCRIPTS = my_script
Script objects can be installed in bindir, sbindir,
libexecdir, or pkgdatadir.
Scripts that need not being installed can be listed in
noinst_SCRIPTS, and among them, those which are needed only by
make check should go in check_SCRIPTS.
Header files are specified by the HEADERS family of variables.
Generally header files are not installed, so the noinst_HEADERS
variable will be the most used. 9
All header files must be listed somewhere; missing ones will not appear
in the distribution. Often it is clearest to list uninstalled headers
with the rest of the sources for a program. See A Program. Headers
listed in a _SOURCES variable need not be listed in any
_HEADERS variable.
Headers can be installed in includedir, oldincludedir, or
pkgincludedir.
Automake supports the installation of miscellaneous data files using the
DATA family of variables.
Such data can be installed in the directories datadir,
sysconfdir, sharedstatedir, localstatedir, or
pkgdatadir.
By default, data files are not included in a distribution. Of course, you can use the dist_ prefix to change this on a per-variable basis.
Here is how Automake declares its auxiliary data files:
dist_pkgdata_DATA = clean-kr.am clean.am ...
Because Automake's automatic dependency tracking works as a side-effect of compilation (see Dependencies) there is a bootstrap issue: a target should not be compiled before its dependencies are made, but these dependencies are unknown until the target is first compiled.
Ordinarily this is not a problem, because dependencies are distributed
sources: they preexist and do not need to be built. Suppose that
foo.c includes foo.h. When it first compiles
foo.o, make only knows that foo.o depends on
foo.c. As a side-effect of this compilation depcomp
records the foo.h dependency so that following invocations of
make will honor it. In these conditions, it's clear there is
no problem: either foo.o doesn't exist and has to be built
(regardless of the dependencies), either accurate dependencies exist and
they can be used to decide whether foo.o should be rebuilt.
It's a different story if foo.h doesn't exist by the first make run. For instance there might be a rule to build foo.h. This time file.o's build will fail because the compiler can't find foo.h. make failed to trigger the rule to build foo.h first by lack of dependency information.
The BUILT_SOURCES variable is a workaround for this problem. A
source file listed in BUILT_SOURCES is made on make all
or make check (or even make install) before other
targets are processed. However, such a source file is not
compiled unless explicitly requested by mentioning it in some
other _SOURCES variable.
So, to conclude our introductory example, we could use
BUILT_SOURCES = foo.h to ensure foo.h gets built before
any other target (including foo.o) during make all or
make check.
BUILT_SOURCES is actually a bit of a misnomer, as any file which
must be created early in the build process can be listed in this
variable. Moreover, all built sources do not necessarily have to be
listed in BUILT_SOURCES. For instance a generated .c file
doesn't need to appear in BUILT_SOURCES (unless it is included by
another source), because it's a known dependency of the associated
object.
It might be important to emphasize that BUILT_SOURCES is
honored only by make all, make check and make
install. This means you cannot build a specific target (e.g.,
make foo) in a clean tree if it depends on a built source.
However it will succeed if you have run make all earlier,
because accurate dependencies are already available.
The next section illustrates and discusses the handling of built sources on a toy example.
Suppose that foo.c includes bindir.h, which is
installation-dependent and not distributed: it needs to be built. Here
bindir.h defines the preprocessor macro bindir to the
value of the make variable bindir (inherited from
configure).
We suggest several implementations below. It's not meant to be an exhaustive listing of all ways to handle built sources, but it will give you a few ideas if you encounter this issue.
This first implementation will illustrate the bootstrap issue mentioned in the previous section (see Sources).
Here is a tentative Makefile.am.
# This won't work.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
nodist_foo_SOURCES = bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo '#define bindir "$(bindir)"' >$@
This setup doesn't work, because Automake doesn't know that foo.c includes bindir.h. Remember, automatic dependency tracking works as a side-effect of compilation, so the dependencies of foo.o will be known only after foo.o has been compiled (see Dependencies). The symptom is as follows.
% make
source='foo.c' object='foo.o' libtool=no \
depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
foo.c:2: bindir.h: No such file or directory
make: *** [foo.o] Error 1
BUILT_SOURCESA solution is to require bindir.h to be built before anything
else. This is what BUILT_SOURCES is meant for (see Sources).
bin_PROGRAMS = foo
foo_SOURCES = foo.c
BUILT_SOURCES = bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo '#define bindir "$(bindir)"' >$@
See how bindir.h get built first:
% make
echo '#define bindir "/usr/local/bin"' >bindir.h
make all-am
make[1]: Entering directory `/home/adl/tmp'
source='foo.c' object='foo.o' libtool=no \
depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
gcc -g -O2 -o foo foo.o
make[1]: Leaving directory `/home/adl/tmp'
However, as said earlier, BUILT_SOURCES applies only to the
all, check, and install targets. It still fails
if you try to run make foo explicitly:
% make clean
test -z "bindir.h" || rm -f bindir.h
test -z "foo" || rm -f foo
rm -f *.o
% : > .deps/foo.Po # Suppress previously recorded dependencies
% make foo
source='foo.c' object='foo.o' libtool=no \
depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
depmode=gcc /bin/sh ./depcomp \
gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
foo.c:2: bindir.h: No such file or directory
make: *** [foo.o] Error 1
Usually people are happy enough with BUILT_SOURCES because they
never build targets such as make foo before make all, as
in the previous example. However if this matters to you, you can
avoid BUILT_SOURCES and record such dependencies explicitly in
the Makefile.am.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
foo.$(OBJEXT): bindir.h
CLEANFILES = bindir.h
bindir.h: Makefile
echo '#define bindir "$(bindir)"' >$@
You don't have to list all the dependencies of foo.o
explicitly, only those which might need to be built. If a dependency
already exists, it will not hinder the first compilation and will be
recorded by the normal dependency tracking code. (Note that after this
first compilation the dependency tracking code will also have recorded
the dependency between foo.o and bindir.h; so our explicit
dependency is really useful to the first build only.)
Adding explicit dependencies like this can be a bit dangerous if you are
not careful enough. This is due to the way Automake tries not to
overwrite your rules (it assumes you know better than it).
foo.$(OBJEXT): bindir.h supersedes any rule Automake may want to
output to build foo.$(OBJEXT). It happens to work in this case
because Automake doesn't have to output any foo.$(OBJEXT):
target: it relies on a suffix rule instead (i.e., .c.$(OBJEXT):).
Always check the generated Makefile.in if you do this.
It's possible to define this preprocessor macro from configure,
either in config.h (see Defining Directories (The Autoconf Manual)), or by processing a
bindir.h.in file using AC_CONFIG_FILES
(see Configuration Actions (The Autoconf Manual)).
At this point it should be clear that building bindir.h from configure work well for this example. bindir.h will exist before you build any target, hence will not cause any dependency issue.
The Makefile can be shrunk as follows. We do not even have to mention bindir.h.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
However, it's not always possible to build sources from configure, especially when these sources are generated by a tool that needs to be built first...
Another attractive idea is to define bindir as a variable or
function exported from bindir.o, and build bindir.c
instead of bindir.h.
noinst_PROGRAMS = foo
foo_SOURCES = foo.c bindir.h
nodist_foo_SOURCES = bindir.c
CLEANFILES = bindir.c
bindir.c: Makefile
echo 'const char bindir[] = "$(bindir)";' >$
bindir.h contains just the variable's declaration and doesn't need to be built, so it won't cause any trouble. bindir.o is always dependent on bindir.c, so bindir.c will get built first.
There is no panacea, of course. Each solution has its merits and drawbacks.
You cannot use BUILT_SOURCES if the ability to run make
foo on a clean tree is important to you.
You won't add explicit dependencies if you are leery of overriding an Automake rule by mistake.
Building files from ./configure is not always possible, neither is converting .h files into .c files.
Since Automake is primarily intended to generate Makefile.ins for use in GNU programs, it tries hard to interoperate with other GNU tools.
Automake provides some support for Emacs Lisp. The LISP primary
is used to hold a list of .el files. Possible prefixes for this
primary are lisp_ and noinst_. Note that if
lisp_LISP is defined, then configure.ac must run
AM_PATH_LISPDIR (see Macros).
Automake will byte-compile all Emacs Lisp source files using the Emacs
found by AM_PATH_LISPDIR, if any was found.
Byte-compiled Emacs Lisp files are not portable among all versions of Emacs, so it makes sense to turn this off if you expect sites to have more than one version of Emacs installed. Furthermore, many packages don't actually benefit from byte-compilation. Still, we recommend that you byte-compile your Emacs Lisp sources. It is probably better for sites with strange setups to cope for themselves than to make the installation less nice for everybody else.
There are two ways to avoid byte-compiling. Historically, we have recommended the following construct.
lisp_LISP = file1.el file2.el
ELCFILES =
ELCFILES is an internal Automake variables that normally lists
all .elc files that must be byte-compiled. Automake defines
ELCFILES automatically from lisp_LISP. Emptying this
variables explicitly prevents byte-compilation to occur.
Since Automake 1.8, we now recommend using lisp_DATA instead. As
in
lisp_DATA = file1.el file2.el
Note that these two constructs are not equivalent. _LISP will
not install a file if Emacs is not installed, while _DATA will
always install its files.
If AM_GNU_GETTEXT is seen in configure.ac, then Automake
turns on support for GNU gettext, a message catalog system for
internationalization
(see GNU Gettext (GNU gettext utilities)).
The gettext support in Automake requires the addition of two
subdirectories to the package, intl and po. Automake
insures that these directories exist and are mentioned in
SUBDIRS.
Lisp sources are not distributed by default. You can prefix the
LISP primary with dist_, as in dist_lisp_LISP or
dist_noinst_LISP, to indicate that these files should be
distributed.
Automake provides support for GNU Libtool (see Introduction (The Libtool Manual)) with the LTLIBRARIES primary. See A Shared Library.
Automake provides some minimal support for Java compilation with the JAVA primary.
Any .java files listed in a _JAVA variable will be
compiled with JAVAC at build time. By default, .class
files are not included in the distribution.
Currently Automake enforces the restriction that only one _JAVA primary can be used in a given Makefile.am. The reason for this restriction is that, in general, it isn't possible to know which .class files were generated from which .java files – so it would be impossible to know which files to install where. For instance, a .java file can define multiple classes; the resulting .class file names cannot be predicted without parsing the .java file.
There are a few variables which are used when compiling Java sources:
JAVACJAVACFLAGSAM_JAVACFLAGSJAVACFLAGS, should be used when it is necessary to put Java
compiler flags into Makefile.am.
JAVAROOTjavac. It defaults to $(top_builddir).
CLASSPATH_ENVsh expression which is used to set the
CLASSPATH environment variable on the javac command line.
(In the future we will probably handle class path setting differently.)
Automake provides support for Python compilation with the PYTHON primary.
Any files listed in a _PYTHON variable will be byte-compiled with
py-compile at install time. py-compile actually creates
both standard (.pyc) and byte-compiled (.pyo) versions of
the source files. Note that because byte-compilation occurs at install
time, any files listed in noinst_PYTHON will not be compiled.
Python source files are included in the distribution by default.
Automake ships with an Autoconf macro called AM_PATH_PYTHON which
will determine some Python-related directory variables (see below). If
you have called AM_PATH_PYTHON from configure.ac, then you
may use the following variables to list you Python source files in your
variables: python_PYTHON, pkgpython_PYTHON,
pyexecdir_PYTHON, pkgpyexecdir_PYTHON, depending where you
want your files installed.
AM_PATH_PYTHON([VERSION], [ACTION-IF-FOUND],
[ACTION-IF-NOT-FOUND]) takes three optional arguments. It will
search a Python interpreter on the system. The first argument, if
present, is the minimum version of Python required for this package:
AM_PATH_PYTHON will skip any Python interpreter which is older
than VERSION. If an interpreter is found and satisfies
VERSION, then ACTION-IF-FOUND is run. Otherwise,
ACTION-IF-NOT-FOUND is run.
If ACTION-IF-NOT-FOUND is not specified, the default is to abort
configure. This is fine when Python is an absolute requirement for the
package. Therefore if Python >= 2.2 is only optional to the
package, AM_PATH_PYTHON could be called as follows.
AM_PATH_PYTHON(2.2,, :)
AM_PATH_PYTHON creates several output variables based on the
Python installation found during configuration.
PYTHON: if no suitable
interpreter could be found.
Assuming ACTION-IF-NOT-FOUND is used (otherwise ./configure
will abort if Python is absent), the value of PYTHON can be used
to setup a conditional in order to disable the relevant part of a build
as follows.
AM_PATH_PYTHON(,, :)
AM_CONDITIONAL([HAVE_PYTHON], [test "$PYTHON" != :])
If the ACTION-IF-NOT-FOUND
is specified
PYTHON_VERSIONsys.version[:3].
PYTHON_PREFIX${prefix}. This term may be used in future work
which needs the contents of Python's sys.prefix, but general
consensus is to always use the value from configure.
PYTHON_EXEC_PREFIX${exec_prefix}. This term may be used in future work
which needs the contents of Python's sys.exec_prefix, but general
consensus is to always use the value from configure.
PYTHON_PLATFORMsys.platform. This value is sometimes needed when
building Python extensions.
pythondirpkgpythondirpythondir which is named after the
package. That is, it is $(pythondir)/$(PACKAGE). It is provided
as a convenience.
pyexecdirpkgpyexecdirAll these directory variables have values that start with either
${prefix} or ${exec_prefix} unexpanded. This works
fine in Makefiles, but it makes these variables hard to use in
configure. This is mandated by the GNU coding standards, so
that the user can run make prefix=/foo install. The Autoconf
manual has a section with more details on this topic
(see Installation Directory Variables (The Autoconf Manual)).
Currently Automake provides support for Texinfo and man pages.
If the current directory contains Texinfo source, you must declare it
with the TEXINFOS primary. Generally Texinfo files are converted
into info, and thus the info_TEXINFOS variable is most commonly used
here. Any Texinfo source file must end in the .texi,
.txi, or .texinfo extension. We recommend .texi
for new manuals.
Automake generates rules to build .info, .dvi, .ps,
.pdf and .html files from your Texinfo sources.
The .info files are built by make all and installed
by make install (unless you use no-installinfo, see below).
The other files can be built on request by make dvi, make ps,
make pdf and make html.
If the .texi file @includes version.texi, then
that file will be automatically generated. The file version.texi
defines four Texinfo flag you can reference using
@value{EDITION}, @value{VERSION},
@value{UPDATED}, and @value{UPDATED-MONTH}.
EDITIONVERSIONUPDATEDUPDATED-MONTHThe version.texi support requires the mdate-sh program;
this program is supplied with Automake and automatically included when
automake is invoked with the --add-missing option.
If you have multiple Texinfo files, and you want to use the version.texi feature, then you have to have a separate version file for each Texinfo file. Automake will treat any include in a Texinfo file that matches vers*.texi just as an automatically generated version file.
Sometimes an info file actually depends on more than one .texi
file. For instance, in GNU Hello, hello.texi includes the file
gpl.texi. You can tell Automake about these dependencies using
the texi_TEXINFOS variable. Here is how GNU Hello does it:
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
By default, Automake requires the file texinfo.tex to appear in
the same directory as the Texinfo source (this can be changed using the
TEXINFO_TEX variable, see below). However, if you used
AC_CONFIG_AUX_DIR in configure.ac (see Finding `configure' Input (The Autoconf Manual)), then
texinfo.tex is looked for there. Automake supplies
texinfo.tex if --add-missing is given.
The option no-texinfo.tex can be used to eliminate the
requirement for texinfo.tex. Use of the variable
TEXINFO_TEX is preferable, however, because that allows the
dvi, ps, and pdf targets to still work.
Automake generates an install-info rule; some people apparently
use this. By default, info pages are installed by make install.
This can be prevented via the no-installinfo option.
The following variables are used by the Texinfo build rules.
MAKEINFOmakeinfo program is
found on the system then it will be used by default; otherwise
missing will be used instead.
MAKEINFOHTML$(MAKEINFO) --html.
MAKEINFOFLAGS$(MAKEINFO) and
$(MAKEINFOHTML). This user variable (see User Variables) is
not expected to be defined in any Makefile; it can be used by
users to pass extra flags to suit their needs.
AM_MAKEINFOFLAGSAM_MAKEINFOHTMLFLAGSmakeinfo invocation. These
are maintainer variables that can be overridden in Makefile.am.
$(AM_MAKEINFOFLAGS) is passed to makeinfo when building
.info files; and $(AM_MAKEINFOHTMLFLAGS) is used when
building .html files.
For instance the following setting can be used to obtain one single .html file per manual, without node separators.
AM_MAKEINFOHTMLFLAGS = --no-headers --no-split
By default, $(AM_MAKEINFOHTMLFLAGS) is set to
$(AM_MAKEINFOFLAGS). This means that defining
$(AM_MAKEINFOFLAGS) without defining
$(AM_MAKEINFOHTMLFLAGS) will impact builds of both .info
and .html files.
TEXI2DVItexi2dvi, a script that ships
with the Texinfo package.
TEXI2PDF$(TEXI2DVI) --pdf --batch.
DVIPSdvips.
TEXINFO_TEXTEXINFO_TEX to tell Automake where to find the canonical
texinfo.tex for your package. The value of this variable should
be the relative path from the current Makefile.am to
texinfo.tex:
TEXINFO_TEX = ../doc/texinfo.tex
A package can also include man pages (but see the GNU standards on this
matter, Man Pages (The GNU Coding Standards).) Man
pages are declared using the MANS primary. Generally the
man_MANS variable is used. Man pages are automatically installed in
the correct subdirectory of mandir, based on the file extension.
File extensions such as .1c are handled by looking for the valid
part of the extension and using that to determine the correct
subdirectory of mandir. Valid section names are the digits
0 through 9, and the letters l and n.
Sometimes developers prefer to name a man page something like foo.man in the source, and then rename it to have the correct suffix, e.g. foo.1, when installing the file. Automake also supports this mode. For a valid section named SECTION, there is a corresponding directory named manSECTIONdir, and a corresponding _MANS variable. Files listed in such a variable are installed in the indicated section. If the file already has a valid suffix, then it is installed as-is; otherwise the file suffix is changed to match the section.
For instance, consider this example:
man1_MANS = rename.man thesame.1 alsothesame.1c
In this case, rename.man will be renamed to rename.1 when installed, but the other files will keep their names.
By default, man pages are installed by make install. However,
since the GNU project does not require man pages, many maintainers do
not expend effort to keep the man pages up to date. In these cases, the
no-installman option will prevent the man pages from being
installed by default. The user can still explicitly install them via
make install-man.
Here is how the man pages are handled in GNU cpio (which includes
both Texinfo documentation and man pages):
man_MANS = cpio.1 mt.1
EXTRA_DIST = $(man_MANS)
Man pages are not currently considered to be source, because it is not uncommon for man pages to be automatically generated. Therefore they are not automatically included in the distribution. However, this can be changed by use of the dist_ prefix.
The nobase_ prefix is meaningless for man pages and is disallowed.
Naturally, Automake handles the details of actually installing your
program once it has been built. All files named by the various
primaries are automatically installed in the appropriate places when the
user runs make install.
A file named in a primary is installed by copying the built file into the appropriate directory. The base name of the file is used when installing.
bin_PROGRAMS = hello subdir/goodbye
In this example, both hello and goodbye will be installed
in $(bindir).
Sometimes it is useful to avoid the basename step at install time. For instance, you might have a number of header files in subdirectories of the source tree which are laid out precisely how you want to install them. In this situation you can use the nobase_ prefix to suppress the base name step. For example:
nobase_include_HEADERS = stdio.h sys/types.h
Will install stdio.h in $(includedir) and types.h
in $(includedir)/sys.
Automake generates separate install-data and install-exec
rules, in case the installer is installing on multiple machines which
share directory structure—these targets allow the machine-independent
parts to be installed only once. install-exec installs
platform-dependent files, and install-data installs
platform-independent files. The install target depends on both
of these targets. While Automake tries to automatically segregate
objects into the correct category, the Makefile.am author is, in
the end, responsible for making sure this is done correctly.
Variables using the standard directory prefixes data,
info, man, include, oldinclude,
pkgdata, or pkginclude (e.g. data_DATA) are
installed by install-data.
Variables using the standard directory prefixes bin, sbin, libexec, sysconf, localstate, lib, or pkglib (e.g. bin_PROGRAMS) are installed by install-exec.
Any variable using a user-defined directory prefix with exec in the name (e.g. myexecbin_PROGRAMS is installed by install-exec. All other user-defined prefixes are installed by install-data.
It is possible to extend this mechanism by defining an
install-exec-local or install-data-local rule. If these
rules exist, they will be run at make install time. These
rules can do almost anything; care is required.
Automake also supports two install hooks, install-exec-hook and
install-data-hook. These hooks are run after all other install
rules of the appropriate type, exec or data, have completed. So, for
instance, it is possible to perform post-installation modifications
using an install hook.
Automake generates support for the DESTDIR variable in all install rules. DESTDIR is used during the make install step to relocate install objects into a staging area. Each object and path is prefixed with the value of DESTDIR before being copied into the install area. Here is an example of typical DESTDIR usage:
make DESTDIR=/tmp/staging install
This places install objects in a directory tree built under /tmp/staging. If /gnu/bin/foo and /gnu/share/aclocal/foo.m4 are to be installed, the above command would install /tmp/staging/gnu/bin/foo and /tmp/staging/gnu/share/aclocal/foo.m4.
This feature is commonly used to build install images and packages. For more information, see Makefile Conventions (The GNU Coding Standards).
Support for DESTDIR is implemented by coding it directly into the
install rules. If your Makefile.am uses a local install rule
(e.g., install-exec-local) or an install hook, then you must
write that code to respect DESTDIR.
Automake also generates rules for targets uninstall,
installdirs, and install-strip.
Automake supports uninstall-local and uninstall-hook.
There is no notion of separate uninstalls for “exec” and “data”, as
these features would not provide additional functionality.
Note that uninstall is not meant as a replacement for a real
packaging tool.
The GNU Makefile Standards specify a number of different clean rules. See See Standard Targets for Users (The GNU Coding Standards).
Generally the files that can be cleaned are determined automatically by
Automake. Of course, Automake also recognizes some variables that can
be defined to specify additional files to clean. These variables are
MOSTLYCLEANFILES, CLEANFILES, DISTCLEANFILES, and
MAINTAINERCLEANFILES.
As the GNU Standards aren't always explicit as to which files should be
removed by which rule, we've adopted a heuristic which we believe was
first formulated by François Pinard:
make built it, and it is commonly something that one would
want to rebuild (for instance, a .o file), then
mostlyclean should delete it.
make built it, then clean should delete it.
configure built it, then distclean should delete it.
maintainer-clean should delete it. However
maintainer-clean should not delete anything that needs to exist
in order to run ./configure && make.
We recommend that you follow this same set of heuristics in your Makefile.am.
The dist rule in the generated Makefile.in can be used
to generate a gzip'd tar file and other flavors of archive for
distribution. The files is named based on the PACKAGE and
VERSION variables defined by AM_INIT_AUTOMAKE
(see Macros); more precisely the gzip'd tar file is named
package-version.tar.gz.
You can use the make variable GZIP_ENV to control how gzip
is run. The default setting is --best.
For the most part, the files to distribute are automatically found by
Automake: all source files are automatically included in a distribution,
as are all Makefile.ams and Makefile.ins. Automake also
has a built-in list of commonly used files which are automatically
included if they are found in the current directory (either physically,
or as the target of a Makefile.am rule). This list is printed by
automake --help. Also, files which are read by configure
(i.e. the source files corresponding to the files specified in various
Autoconf macros such as AC_CONFIG_FILES and siblings) are
automatically distributed. Files included in Makefile.ams (using
include) or in configure.ac (using m4_include), and
helper scripts installed with automake --add-missing are also
distributed.
Still, sometimes there are files which must be distributed, but which
are not covered in the automatic rules. These files should be listed in
the EXTRA_DIST variable. You can mention files from
subdirectories in EXTRA_DIST.
You can also mention a directory in EXTRA_DIST; in this case the
entire directory will be recursively copied into the distribution.
Please note that this will also copy everything in the directory,
including CVS/RCS version control files. We recommend against using
this feature.
If you define SUBDIRS, Automake will recursively include the
subdirectories in the distribution. If SUBDIRS is defined
conditionally (see Conditionals), Automake will normally include all
directories that could possibly appear in SUBDIRS in the
distribution. If you need to specify the set of directories
conditionally, you can set the variable DIST_SUBDIRS to the exact
list of subdirectories to include in the distribution (see Top level).
Sometimes you need tighter control over what does not go into the distribution; for instance you might have source files which are generated and which you do not want to distribute. In this case Automake gives fine-grained control using the dist and nodist prefixes. Any primary or _SOURCES variable can be prefixed with dist_ to add the listed files to the distribution. Similarly, nodist_ can be used to omit the files from the distribution. As an example, here is how you would cause some data to be distributed while leaving some source code out of the distribution:
dist_data_DATA = distribute-this
bin_PROGRAMS = foo
nodist_foo_SOURCES = do-not-distribute.c
Occasionally it is useful to be able to change the distribution before
it is packaged up. If the dist-hook rule exists, it is run
after the distribution directory is filled, but before the actual tar
(or shar) file is created. One way to use this is for distributing
files in subdirectories for which a new Makefile.am is overkill:
dist-hook:
mkdir $(distdir)/random
cp -p $(srcdir)/random/a1 $(srcdir)/random/a2 $(distdir)/random
Another way to to use this is for removing unnecessary files that get recursively included by specifying a directory in EXTRA_DIST:
EXTRA_DIST = doc
dist-hook:
rm -rf `find $(distdir)/doc -name CVS`
Two variables that come handy when writing dist-hook rules are
$(distdir) and $(top_distdir).
$(distdir) points to the directory where the dist rule
will copy files from the current directory before creating the
tarball. If you are at the top-level directory, then distdir =
$(PACKAGE)-$(VERSION). When used from subdirectory named
foo/, then distdir = ../$(PACKAGE)-$(VERSION)/foo.
$(top_distdir) always points to the root directory of the
distributed tree. At the top-level it's equal to $(distdir).
In the foo/ subdirectory
top_distdir = ../$(PACKAGE)-$(VERSION).
Note that when packages are nested using AC_CONFIG_SUBDIRS
(see AC_CONFIG_SUBDIRS (The Autoconf Manual)), then
$(distdir) and $(top_distdir) are relative to the
package where make dist was run, not to any sub-packages
involved.
Automake also generates a distcheck rule which can be of help
to ensure that a given distribution will actually work.
distcheck makes a distribution, then tries to do a VPATH
build, run the test suite, and finally make another tarfile to ensure the
distribution is self-contained.
Building the package involves running ./configure. If you need
to supply additional flags to configure, define them in the
DISTCHECK_CONFIGURE_FLAGS variable, either in your top-level
Makefile.am, or on the command line when invoking make.
If the distcheck-hook rule is defined in your
Makefile.am, then it will be invoked by distcheck after
the new distribution has been unpacked, but before the unpacked copy
is configured and built. Your distcheck-hook can do almost
anything, though as always caution is advised. Generally this hook is
used to check for potential distribution errors not caught by the
standard mechanism.
Speaking about potential distribution errors, distcheck will also
ensure that the distclean rule actually removes all built
files. This is done by running make distcleancheck at the end of
the VPATH build. By default, distcleancheck will run
distclean and then make sure the build tree has been emptied by
running $(distcleancheck_listfiles). Usually this check will
find generated files that you forgot to add to the DISTCLEANFILES
variable (see Clean).
The distcleancheck behavior should be OK for most packages,
otherwise you have the possibility to override the definition of
either the distcleancheck rule, or the
$(distcleancheck_listfiles) variable. For instance to disable
distcleancheck completely, add the following rule to your
top-level Makefile.am:
distcleancheck:
@:
If you want distcleancheck to ignore built files which have not
been cleaned because they are also part of the distribution, add the
following definition instead:
distcleancheck_listfiles = \
find -type f -exec sh -c 'test -f $(srcdir)/{} || echo {}' ';'
The above definition is not the default because it's usually an error if
your Makefiles cause some distributed files to be rebuilt when the user
build the package. (Think about the user missing the tool required to
build the file; or if the required tool is built by your package,
consider the cross-compilation case where it can't be run.) There is
a FAQ entry about this (see distcleancheck), make sure you read it
before playing with distcleancheck_listfiles.
distcheck also checks that the uninstall rule works
properly, both for ordinary and DESTDIR builds. It does this
by invoking make uninstall, and then it checks the install tree
to see if any files are left over. This check will make sure that you
correctly coded your uninstall-related rules.
By default, the checking is done by the distuninstallcheck rule,
and the list of files in the install tree is generated by
$(distuninstallcheck_listfiles) (this is a variable whose value is
a shell command to run that prints the list of files to stdout).
Either of these can be overridden to modify the behavior of
distcheck. For instance, to disable this check completely, you
would write:
distuninstallcheck:
@:
Automake generates rules to provide archives of the project for distributions in various formats. Their targets are:
dist-bzip2dist-gzipdist-shardist-zipdist-tarZThe rule dist (and its historical synonym dist-all) will
create archives in all the enabled formats, Options. By
default, only the dist-gzip target is hooked to dist.
Automake supports two forms of test suites.
If the variable TESTS is defined, its value is taken to be a list
of programs to run in order to do the testing. The programs can either
be derived objects or source objects; the generated rule will look both
in srcdir and .. Programs needing data files should look
for them in srcdir (which is both an environment variable and a
make variable) so they work when building in a separate directory
(see Build Directories (The Autoconf Manual)), and in particular for the distcheck rule
(see Dist).
The number of failures will be printed at the end of the run. If a given test program exits with a status of 77, then its result is ignored in the final count. This feature allows non-portable tests to be ignored in environments where they don't make sense.
The variable TESTS_ENVIRONMENT can be used to set environment
variables for the test run; the environment variable srcdir is
set in the rule. If all your test programs are scripts, you can also
set TESTS_ENVIRONMENT to an invocation of the shell (e.g.
$(SHELL) -x); this can be useful for debugging the tests.
You may define the variable XFAIL_TESTS to a list of tests
(usually a subset of TESTS) that are expected to fail. This will
reverse the result of those tests.
Automake ensures that each program listed in TESTS is built
before any tests are run; you can list both source and derived programs
in TESTS. For instance, you might want to run a C program as a
test. To do this you would list its name in TESTS and also in
check_PROGRAMS, and then specify it as you would any other
program.
If dejagnu appears in
AUTOMAKE_OPTIONS, then a dejagnu-based test suite is
assumed. The variable DEJATOOL is a list of names which are
passed, one at a time, as the --tool argument to runtest
invocations; it defaults to the name of the package.
The variable RUNTESTDEFAULTFLAGS holds the --tool and
--srcdir flags that are passed to dejagnu by default; this can be
overridden if necessary.
The variables EXPECT and RUNTEST can
also be overridden to provide project-specific values. For instance,
you will need to do this if you are testing a compiler toolchain,
because the default values do not take into account host and target
names.
The contents of the variable RUNTESTFLAGS are passed to the
runtest invocation. This is considered a “user variable”
(see User Variables). If you need to set runtest flags in
Makefile.am, you can use AM_RUNTESTFLAGS instead.
Automake will generate rules to create a local site.exp file,
defining various variables detected by ./configure. This file
is automatically read by DejaGnu. It is OK for the user of a package
to edit this file in order to tune the test suite. However this is
not the place where the test suite author should define new variables:
this should be done elsewhere in the real test suite code.
Especially, site.exp should not be distributed.
For more information regarding DejaGnu test suites, see See Top (The DejaGnu Manual).
In either case, the testing is done via make check.
The installcheck target is available to the user as a way to
run any tests after the package has been installed. You can add tests
to this by writing an installcheck-local rule.
Automake generates rules to automatically rebuild Makefiles, configure, and other derived files like Makefile.in.
If you are using AM_MAINTAINER_MODE in configure.ac, then
these automatic rebuilding rules are only enabled in maintainer mode.
Sometimes you need to run aclocal with an argument like -I
to tell it where to find .m4 files. Since sometimes make
will automatically run aclocal, you need a way to specify these
arguments. You can do this by defining ACLOCAL_AMFLAGS; this
holds arguments which are passed verbatim to aclocal. This variable
is only useful in the top-level Makefile.am.
Sometimes it is convenient to supplement the rebuild rules for
configure or config.status with additional dependencies.
The variables CONFIGURE_DEPENDENCIES and
CONFIG_STATUS_DEPENDENCIES can be used to list these extra
dependencies. These variable should be defined in all
Makefiles of the tree (because these two rebuild rules are
output in all them), so it is safer and easier to AC_SUBST them
from configure.ac. For instance the following statement will
cause configure to be rerun each time version.sh is
changed.
AC_SUBST([CONFIG_STATUS_DEPENDENCIES], ['$(top_srcdir)/version.sh'])
Note the $(top_srcdir)/ in the filename. Since this variable
is to be used in all Makefiles, its value must be sensible at
any level in the build hierarchy.
Beware not to mistake CONFIGURE_DEPENDENCIES for
CONFIG_STATUS_DEPENDENCIES.
CONFIGURE_DEPENDENCIES adds dependencies to the
configure rule, whose effect is to run autoconf. This
variable should be seldom used, because automake already tracks
m4_included files. However it can be useful when playing
tricky games with m4_esyscmd or similar non-recommendable
macros with side effects.
CONFIG_STATUS_DEPENDENCIES adds dependencies to the
config.status rule, whose effect is to run configure.
This variable should therefore carry any non-standard source that may
be read as a side effect of running configure, like version.sh
in the example above.
Speaking of version.sh scripts, we recommend against them today. They are mainly used when the version of a package is updated automatically by a script (e.g., in daily builds). Here is what some old-style configure.acs may look like:
AC_INIT
. $srcdir/version.sh
AM_INIT_AUTOMAKE([name], $VERSION_NUMBER)
...
Here, version.sh is a shell fragment that sets
VERSION_NUMBER. The problem with this example is that
automake cannot track dependencies (listing version.sh
in CONFIG_STATUS_DEPENDENCIES, and distributing this file is up
to the user), and that it uses the obsolete form of AC_INIT and
AM_INIT_AUTOMAKE. Upgrading to the new syntax is not
straightforward, because shell variables are not allowed in
AC_INIT's arguments. We recommend that version.sh be
replaced by an M4 file that is included by configure.ac:
m4_include([version.m4])
AC_INIT([name], VERSION_NUMBER)
AM_INIT_AUTOMAKE
...
Here version.m4 could contain something like
m4_define([VERSION_NUMBER], [1.2]). The advantage of this
second form is that automake will take care of the dependencies
when defining the rebuild rule, and will also distribute the file
automatically. An inconvenience is that autoconf will now be
rerun each time the version number is bumped, when only
configure had to be rerun in the previous setup.
Various features of Automake can be controlled by options in the
Makefile.am. Such options are applied on a per-Makefile
basis when listed in a special Makefile variable named
AUTOMAKE_OPTIONS. They are applied globally to all processed
Makefiles when listed in the first argument of
AM_INIT_AUTOMAKE in configure.ac. Currently understood
options are:
gnitsgnuforeigncygnusgnits option also implies
readme-alpha and check-news.
ansi2knr/ansi2knrcheck-newsmake dist to fail unless the current version number appears
in the first few lines of the NEWS file.
dejagnudejagnu-specific rules to be generated. See Tests.
dist-bzip2dist-bzip2 to dist.
dist-shardist-shar to dist.
dist-zipdist-zip to dist.
dist-tarZdist-tarZ to dist.
no-defineAM_INIT_AUTOMAKE. It will prevent the PACKAGE and
VERSION variables to be AC_DEFINEd.
no-dependenciesno-distdist target. This is useful
when a package has its own method for making distributions.
no-dist-gzipdist-gzip to dist.
no-exeextEXEEXT is found to be empty. However, by
default automake will generate an error for this use. The
no-exeext option will disable this error. This is intended for
use only where it is known in advance that the package will not be
ported to Windows, or any other operating system using extensions on
executables.
no-installinfoinfo and install-info
targets will still be available. This option is disallowed at
GNU strictness and above.
no-installmaninstall-man target will still
be available for optional installation. This option is disallowed at
GNU strictness and above.
nostdincno-texinfo.texreadme-alphastd-optionsinstallcheck rule check that installed scripts and
programs support the --help and --version options.
This also provides a basic check that the program's
run-time dependencies are satisfied after installation.
In a few situations, programs (or scripts) have to be exempted from this
test. For instance false (from GNU sh-utils) is never
successful, even for --help or --version. You can list
such programs in the variable AM_INSTALLCHECK_STD_OPTIONS_EXEMPT.
Programs (not scripts) listed in this variable should be suffixed by
$(EXEEXT) for the sake of Win32 or OS/2. For instance suppose we
build false as a program but true.sh as a script, and that
neither of them support --help or --version:
AUTOMAKE_OPTIONS = std-options
bin_PROGRAMS = false ...
bin_SCRIPTS = true.sh ...
AM_INSTALLCHECK_STD_OPTIONS_EXEMPT = false$(EXEEXT) true.sh
subdir-objects-Wcategory or --warnings=categoryAM_INIT_AUTOMAKE([-Wall])
in your configure.ac.
Unrecognized options are diagnosed by automake.
If you want an option to apply to all the files in the tree, you can use
the AM_INIT_AUTOMAKE macro in configure.ac.
See Macros.
There are a few rules and variables that didn't fit anywhere else.
etagsAutomake will generate rules to generate TAGS files for use with GNU Emacs under some circumstances.
If any C, C++ or Fortran 77 source code or headers are present, then
tags and TAGS rules will be generated for the directory.
At the topmost directory of a multi-directory package, a tags
rule will be output which, when run, will generate a TAGS file
that includes by reference all TAGS files from subdirectories.
The tags rule will also be generated if the variable
ETAGS_ARGS is defined. This variable is intended for use in
directories which contain taggable source that etags does not
understand. The user can use the ETAGSFLAGS to pass additional
flags to etags; AM_ETAGSFLAGS is also available for use
in Makefile.am.
Here is how Automake generates tags for its source, and for nodes in its
Texinfo file:
ETAGS_ARGS = automake.in --lang=none \
--regex='/^@node[ \t]+\([^,]+\)/\1/' automake.texi
If you add filenames to ETAGS_ARGS, you will probably also
want to set TAGS_DEPENDENCIES. The contents of this variable
are added directly to the dependencies for the tags rule.
Automake also generates a ctags rule which can be used to
build vi-style tags files. The variable CTAGS
is the name of the program to invoke (by default ctags);
CTAGSFLAGS can be used by the user to pass additional flags,
and AM_CTAGSFLAGS can be used by the Makefile.am.
Automake will also generate an ID rule which will run
mkid on the source. This is only supported on a
directory-by-directory basis.
Automake also supports the GNU Global Tags program. The GTAGS rule runs Global Tags
automatically and puts the result in the top build directory. The
variable GTAGS_ARGS holds arguments which are passed to
gtags.
It is sometimes useful to introduce a new implicit rule to handle a file type that Automake does not know about.
For instance, suppose you had a compiler which could compile .foo files to .o files. You would simply define an suffix rule for your language:
.foo.o:
foocc -c -o $@ $<
Then you could directly use a .foo file in a _SOURCES variable and expect the correct results:
bin_PROGRAMS = doit
doit_SOURCES = doit.foo
This was the simpler and more common case. In other cases, you will
have to help Automake to figure which extensions you are defining your
suffix rule for. This usually happens when your extensions does not
start with a dot. Then, all you have to do is to put a list of new
suffixes in the SUFFIXES variable before you define your
implicit rule.
For instance the following definition prevents Automake to misinterpret .idlC.cpp: as an attempt to transform .idlC into .cpp.
SUFFIXES = .idl C.cpp
.idlC.cpp:
# whatever
As you may have noted, the SUFFIXES variable behaves like the
.SUFFIXES special target of make. You should not touch
.SUFFIXES yourself, but use SUFFIXES instead and let
Automake generate the suffix list for .SUFFIXES. Any given
SUFFIXES go at the start of the generated suffixes list, followed
by Automake generated suffixes not already in the list.
Automake has support for an obscure feature called multilibs. A multilib is a library which is built for multiple different ABIs at a single time; each time the library is built with a different target flag combination. This is only useful when the library is intended to be cross-compiled, and it is almost exclusively used for compiler support libraries.
The multilib support is still experimental. Only use it if you are familiar with multilibs and can debug problems you might encounter.
Automake supports an include directive which can be used to
include other Makefile fragments when automake is run.
Note that these fragments are read and interpreted by automake,
not by make. As with conditionals, make has no idea that
include is in use.
There are two forms of include:
include $(srcdir)/fileinclude $(top_srcdir)/fileNote that if a fragment is included inside a conditional, then the condition applies to the entire contents of that fragment.
Makefile fragments included this way are always distributed because there are needed to rebuild Makefile.in.
Automake supports a simple type of conditionals.
Before using a conditional, you must define it by using
AM_CONDITIONAL in the configure.ac file (see Macros).
The conditional name, conditional, should be a simple string starting with a letter and containing only letters, digits, and underscores. It must be different from TRUE and FALSE which are reserved by Automake.
The shell condition (suitable for use in a shell
ifstatement) is evaluated whenconfigureis run. Note that you must arrange for everyAM_CONDITIONALto be invoked every timeconfigureis run – ifAM_CONDITIONALis run conditionally (e.g., in a shellifstatement), then the result will confuse automake.
Conditionals typically depend upon options which the user provides to
the configure script. Here is an example of how to write a
conditional which is true if the user uses the --enable-debug
option.
AC_ARG_ENABLE(debug,
[ --enable-debug Turn on debugging],
[case "${enableval}" in
yes) debug=true ;;
no) debug=false ;;
*) AC_MSG_ERROR(bad value ${enableval} for --enable-debug) ;;
esac],[debug=false])
AM_CONDITIONAL(DEBUG, test x$debug = xtrue)
Here is an example of how to use that conditional in Makefile.am:
if DEBUG
DBG = debug
else
DBG =
endif
noinst_PROGRAMS = $(DBG)
This trivial example could also be handled using EXTRA_PROGRAMS (see Conditional Programs).
You may only test a single variable in an if statement, possibly
negated using !. The else statement may be omitted.
Conditionals may be nested to any depth. You may specify an argument to
else in which case it must be the negation of the condition used
for the current if. Similarly you may specify the condition
which is closed by an end:
if DEBUG
DBG = debug
else !DEBUG
DBG =
endif !DEBUG
Unbalanced conditions are errors.
Note that conditionals in Automake are not the same as conditionals in
GNU Make. Automake conditionals are checked at configure time by the
configure script, and affect the translation from
Makefile.in to Makefile. They are based on options passed
to configure and on results that configure has discovered
about the host system. GNU Make conditionals are checked at make
time, and are based on variables passed to the make program or defined
in the Makefile.
Automake conditionals will work with any make program.
--gnu and --gnits
The --gnu option (or gnu in the AUTOMAKE_OPTIONS
variable) causes automake to check the following:
Note that this option will be extended in the future to do even more
checking; it is advisable to be familiar with the precise requirements
of the GNU standards. Also, --gnu can require certain
non-standard GNU programs to exist for use by various maintainer-only
rules; for instance in the future pathchk might be required for
make dist.
The --gnits option does everything that --gnu does, and checks the following as well:
--help
and --version really print a usage message and a version string,
respectively. This is the std-options option (see Options).
--cygnusSome packages, notably GNU GCC and GNU gdb, have a build environment originally written at Cygnus Support (subsequently renamed Cygnus Solutions, and then later purchased by Red Hat). Packages with this ancestry are sometimes referred to as “Cygnus” trees.
A Cygnus tree has slightly different rules for how a Makefile.in
is to be constructed. Passing --cygnus to automake will
cause any generated Makefile.in to comply with Cygnus rules.
Here are the precise effects of --cygnus:
runtest, expect,
makeinfo and texi2dvi.
--foreign is implied.
check target doesn't depend on all.
GNU maintainers are advised to use gnu strictness in preference to the special Cygnus mode. Some day, perhaps, the differences between Cygnus trees and GNU trees will disappear (for instance, as GCC is made more standards compliant). At that time the special Cygnus mode will be removed.
With some minor exceptions (like _PROGRAMS variables being
rewritten to append $(EXEEXT)), the contents of a
Makefile.am is copied to Makefile.in verbatim.
These copying semantics means that many problems can be worked around
by simply adding some make variables and rules to
Makefile.am. Automake will ignore these additions.
Since a Makefile.in is built from data gathered from three
different places (Makefile.am, configure.ac, and
automake itself), it is possible to have conflicting
definitions of rules or variables. When building Makefile.in
the following priorities are respected by automake to ensure
the user always have the last word. User defined variables in
Makefile.am have priority over variables AC_SUBSTed from
configure.ac, and AC_SUBSTed variables have priority
over automake-defined variables. As far rules are
concerned, a user-defined rule overrides any
automake-defined rule for the same target.
These overriding semantics make it possible to fine tune some default
settings of Automake, or replace some of its rules. Overriding
Automake rules is often inadvisable, particularly in the topmost
directory of a package with subdirectories. The -Woverride
option (see Invoking Automake) comes handy to catch overridden
definitions.
Note that Automake does not make any difference between rules with
commands and rules that only specify dependencies. So it is not
possible to append new dependencies to an automake-defined
target without redefining the entire rule.
However, various useful targets have a -local version you can specify in your Makefile.in. Automake will supplement the standard target with these user-supplied targets.
The targets that support a local version are all, info,
dvi, ps, pdf, html, check,
install-data, install-exec, uninstall,
installdirs, installcheck and the various clean targets
(mostlyclean, clean, distclean, and
maintainer-clean). Note that there are no
uninstall-exec-local or uninstall-data-local targets; just
use uninstall-local. It doesn't make sense to uninstall just
data or just executables.
For instance, here is one way to install a file in /etc:
install-data-local:
$(INSTALL_DATA) $(srcdir)/afile $(DESTDIR)/etc/afile
Some rule also have a way to run another rule, called a hook,
after their work is done. The hook is named after the principal target,
with -hook appended. The targets allowing hooks are
install-data, install-exec, uninstall, dist,
and distcheck.
For instance, here is how to create a hard link to an installed program:
install-exec-hook:
ln $(DESTDIR)$(bindir)/program$(EXEEXT) \
$(DESTDIR)$(bindir)/proglink$(EXEEXT)
Although cheaper and more portable than symbolic links, hard links
will not work everywhere (for instance OS/2 does not have
ln). Ideally you should fall back to cp -p when
ln does not work. An easy way, if symbolic links are
acceptable to you, is to add AC_PROG_LN_S to
configure.ac (see Particular Program Checks (The Autoconf Manual)) and use $(LN_S) in
Makefile.am.
For instance, here is how you could install a versioned copy of a
program using $(LN_S):
install-exec-hook:
cd $(DESTDIR)$(bindir) && \
mv -f prog$(EXEEXT) prog-$(VERSION)$(EXEEXT) && \
$(LN_S) prog-$(VERSION)$(EXEEXT) prog$(EXEEXT)
Note that we rename the program so that a new version will erase the
symbolic link, not the real binary. Also we cd into the
destination directory in order to create relative links.
Automake places no restrictions on the distribution of the resulting Makefile.ins. We still encourage software authors to distribute their work under terms like those of the GPL, but doing so is not required to use Automake.
Some of the files that can be automatically installed via the
--add-missing switch do fall under the GPL. However, these also
have a special exception allowing you to distribute them with your
package, regardless of the licensing you choose.
New Automake releases usually include bug fixes and new features. Unfortunately they may also introduce new bugs and incompatibilities. This makes four reasons why a package may require a particular Automake version.
Things get worse when maintaining a large tree of packages, each one requiring a different version of Automake. In the past, this meant that any developer (and sometime users) had to install several versions of Automake in different places, and switch $PATH appropriately for each package.
Starting with version 1.6, Automake installs versioned binaries. This means you can install several versions of Automake in the same $prefix, and can select an arbitrary Automake version by running automake-1.6 or automake-1.7 without juggling with $PATH. Furthermore, Makefile's generated by Automake 1.6 will use automake-1.6 explicitly in their rebuild rules.
Note that 1.6 in automake-1.6 is Automake's API version, not Automake's version. If a bug fix release is made, for instance Automake 1.6.1, the API version will remain 1.6. This means that a package which work with Automake 1.6 should also work with 1.6.1; after all, this is what people expect from bug fix releases.
Note that if your package relies on a feature or a bug fix introduced in a release, you can pass this version as an option to Automake to ensure older releases will not be used. For instance, use this in your configure.ac:
AM_INIT_AUTOMAKE(1.6.1) dnl Require Automake 1.6.1 or better.
or, in a particular Makefile.am:
AUTOMAKE_OPTIONS = 1.6.1 # Require Automake 1.6.1 or better.
Automake will print an error message if its version is older than the requested version.
Automake's programming interface is not easy to define. Basically it should include at least all documented variables and targets that a Makefile.am author can use, any behavior associated with them (e.g. the places where -hook's are run), the command line interface of automake and aclocal, ...
Every undocumented variable, target, or command line option, is not part of the API. You should avoid using them, as they could change from one version to the other (even in bug fix releases, if this helps to fix a bug).
If it turns out you need to use such a undocumented feature, contact automake@gnu.org and try to get it documented and exercised by the test-suite.
This chapter covers some questions that often come up on the mailing lists.
Packages made with Autoconf and Automake ship with some generated files like configure or Makefile.in. These files were generated on the developer's host and are distributed so that end-users do not have to install the maintainer tools required to rebuild them. Other generated files like Lex scanners, Yacc parsers, or Info documentation, are usually distributed on similar grounds.
Automake outputs rules in Makefiles to rebuild these files. For instance make will run autoconf to rebuild configure whenever configure.ac is changed. This makes development safer by ensuring a configure is never out-of-date with respect to configure.ac.
As generated files shipped in packages are up-to-date, and because tar preserves times-tamps, these rebuild rules are not triggered when a user unpacks and builds a package.
Unless you use CVS keywords (in which case files must be updated at
commit time), CVS preserves timestamp during cvs commit and
cvs import -d operations.
When you check out a file using cvs checkout its timestamp is
set to that of the revision which is being checked out.
However, during cvs update, files will have the date of the update, not the original timestamp of this revision. This is meant to make sure that make notices sources files have been updated.
This times tamp shift is troublesome when both sources and generated
files are kept under CVS. Because CVS processes files in alphabetical
order, configure.ac will appear older than configure
after a cvs update that updates both files, even if
configure was newer than configure.ac when it was
checked in. Calling make will then trigger a spurious rebuild
of configure.
There are basically two clans amongst maintainers: those who keep all distributed files under CVS, including generated files, and those who keep generated files out of CVS.
Actually, calls to such tools are all wrapped into a call to the missing script discussed later (see maintainer-mode). missing will take care of fixing the timestamps when these tools are not installed, so that the build can continue.
AM_MAINTAINER_MODE, which will
disable all these rebuild rules by default. This is further discussed
in maintainer-mode.
For instance, suppose a developer has modified Makefile.am and rebuilt Makefile.in, and then decide to do a last-minute change to Makefile.am right before checking in both files (without rebuilding Makefile.in to account for the change).
This last change to Makefile.am make the copy of
Makefile.in out-of-date. Since CVS processes files
alphabetically, when another developer cvs update his or her
tree, Makefile.in will happen to be newer than
Makefile.am. This other developer will not see
Makefile.in is out-of-date.
One way to get CVS and make working peacefully is to never
store generated files in CVS, i.e., do not CVS-control files which
are Makefile targets (also called derived files).
This way developers are not annoyed by changes to generated files. It does not matter if they all have different versions (assuming they are compatible, of course). And finally, timestamps are not lost, changes to sources files can't be missed as in the Makefile.am/Makefile.in example discussed earlier.
The drawback is that the CVS repository is not an exact copy of what is distributed and that users now need to install various development tools (maybe even specific versions) before they can build a checkout. But, after all, CVS's job is versioning, not distribution.
Allowing developers to use different versions of their tools can also hide bugs during distributed development. Indeed, developers will be using (hence testing) their own generated files, instead of the generated files that will be released actually. The developer who prepares the tarball might be using a version of the tool that produces bogus output (for instance a non-portable C file), something other developers could have noticed if they weren't using their own versions of this tool.
Another class of files not discussed here (because they do not cause timestamp issues) are files which are shipped with a package, but maintained elsewhere. For instance tools like gettextize and autopoint (from Gettext) or libtoolize (from Libtool), will install or update files in your package.
These files, whether they are kept under CVS or not, raise similar concerns about version mismatch between developers' tools. The Gettext manual has a section about this, see CVS Issues (GNU gettext tools).
AM_MAINTAINER_MODEThe missing script is a wrapper around several maintainer tools, designed to warn users if a maintainer tool is required but missing. Typical maintainer tools are autoconf, automake, bison, etc. Because file generated by these tools are shipped with the other sources of a package, these tools shouldn't be required during a user build and they are not checked for in configure.
However, if for some reason a rebuild rule is triggered and involves a
missing tool, missing will notice it and warn the user.
Besides the warning, when a tool is missing, missing will
attempt to fix timestamps in a way which allow the build to continue.
For instance missing will touch configure if
autoconf is not installed. When all distributed files are
kept under CVS, this feature of missing allows user
with no maintainer tools to build a package off CVS, bypassing
any timestamp inconsistency implied by cvs update.
If the required tool is installed, missing will run it and
won't attempt to continue after failures. This is correct during
development: developers love fixing failures. However, users with
wrong versions of maintainer tools may get an error when the rebuild
rule is spuriously triggered, halting the build. This failure to let
the build continue is one of the arguments of the
AM_MAINTAINER_MODE advocates.
AM_MAINTAINER_MODE
AM_MAINTAINER_MODE disables the so called "rebuild rules" by
default. If you have AM_MAINTAINER_MODE in
configure.ac, and run ./configure && make, then
make will *never* attempt to rebuilt configure,
Makefile.ins, Lex or Yacc outputs, etc. I.e., this disables
build rules for files which are usually distributed and that users
should normally not have to update.
If you run ./configure --enable-maintainer-mode, then these
rebuild rules will be active.
People use AM_MAINTAINER_MODE either because they do want their
users (or themselves) annoyed by timestamps lossage (see CVS), or
because they simply can't stand the rebuild rules and prefer running
maintainer tools explicitly.
AM_MAINTAINER_MODE also allows you to disable some custom build
rules conditionally. Some developers use this feature to disable
rules that need exotic tools that users may not have available.
Several years ago François Pinard pointed out several arguments
against AM_MAINTAINER_MODE. Most of them relate to insecurity.
By removing dependencies you get non-dependable builds: change to
sources files can have no effect on generated files and this can be
very confusing when unnoticed. He adds that security shouldn't be
reserved to maintainers (what --enable-maintainer-mode
suggests), on the contrary. If one user has to modify a
Makefile.am, then either Makefile.in should be updated
or a warning should be output (this is what Automake uses
missing for) but the last thing you want is that nothing
happens and the user doesn't notice it (this is what happens when
rebuild rules are disabled by AM_MAINTAINER_MODE).
Jim Meyering, the inventor of the AM_MAINTAINER_MODE macro was
swayed by François's arguments, and got rid of
AM_MAINTAINER_MODE in all of his packages.
Still many people continue to use AM_MAINTAINER_MODE, because
it helps them working on projects where all files are kept under CVS,
and because missing isn't enough if you have the wrong
version of the tools.
Developers are lazy. They often would like to use wildcards in Makefile.ams, so they don't need to remember they have to update Makefile.ams every time they add, delete, or rename a file.
There are several objections to this:
cvs add or cvs rm anyway. Updating
Makefile.am accordingly quickly becomes a reflex.
Conversely, if your application doesn't compile
because you forgot to add a file in Makefile.am, it will help
you remember to cvs add it.
make dist will complain. Besides, you don't distribute
more than what you listed.
Still, these are philosophical objections, and as such you may disagree, or find enough value in wildcards to dismiss all of them. Before you start writing a patch against Automake to teach it about wildcards, let's see the main technical issue: portability.
Although $(wildcard ...) works with GNU make, it is
not portable to other make implementations.
The only way Automake could support $(wildcard ...) is by
expending $(wildcard ...) when automake is run.
Resulting Makefile.ins would be portable since they would
list all files and not use $(wildcard ...). However that
means developers need to remember they must run automake each
time they add, delete, or rename files.
Compared to editing Makefile.am, this is really little win. Sure,
it's easier and faster to type automake; make than to type
emacs Makefile.am; make. But nobody bothered enough to write a
patch add support for this syntax. Some people use scripts to
generated file lists in Makefile.am or in separate
Makefile fragments.
Even if you don't care about portability, and are tempted to use
$(wildcard ...) anyway because you target only GNU Make, you
should know there are many places where Automake need to know exactly
which files should be processed. As Automake doesn't know how to
expand $(wildcard ...), you cannot use it in these places.
$(wildcard ...) is a black box comparable to AC_SUBSTed
variables as far Automake is concerned.
You can get warnings about $(wildcard ...) constructs using the
-Wportability flag.
This is a diagnostic you might encounter while running make
distcheck.
As explained in Dist, make distcheck attempts to build
and check your package for errors like this one.
make distcheck will perform a VPATH build of your
package, and then call make distclean. Files left in the build
directory after make distclean has run are listed after this
error.
This diagnostic really covers two kinds of errors:
The former left-over files are not distributed, so the fix is to mark them for cleaning (see Clean), this is obvious and doesn't deserve more explanations.
The latter bug is not always easy to understand and fix, so let's
proceed with an example. Suppose our package contains a program for
which we want to build a man page using help2man. GNU
help2man produces simple manual pages from the --help
and --version output of other commands (see Overview (The Help2man Manual)). Because we don't to force want our
users to install help2man, we decide to distribute the
generated man page using the following setup.
# This Makefile.am is bogus.
bin_PROGRAMS = foo
foo_SOURCES = foo.c
dist_man_MANS = foo.1
foo.1: foo$(EXEEXT)
help2man --output=foo.1 ./foo$(EXEEXT)
This will effectively distribute the man page. However,
make distcheck will fail with:
ERROR: files left in build directory after distclean:
./foo.1
Why was foo.1 rebuilt? Because although distributed, foo.1 depends on a non-distributed built file: foo$(EXEEXT). foo$(EXEEXT) is built by the user, so it will always appear to be newer than the distributed foo.1.
make distcheck caught an inconsistency in our package. Our
intent was to distribute foo.1 so users do not need installing
help2man, however since this our rule causes this file to be
always rebuilt, users do need help2man. Either we
should ensure that foo.1 is not rebuilt by users, or there is
no point in distributing foo.1.
More generally, the rule is that distributed files should never depend on non-distributed built files. If you distribute something generated, distribute its sources.
One way to fix the above example, while still distributing foo.1 is to not depend on foo$(EXEEXT). For instance, assuming foo --version and foo --help do not change unless foo.c or configure.ac change, we could write the following Makefile.am:
bin_PROGRAMS = foo
foo_SOURCES = foo.c
dist_man_MANS = foo.1
foo.1: foo.c $(top_srcdir)/configure.ac
$(MAKE) $(AM_MAKEFLAGS) foo$(EXEEXT)
help2man --output=foo.1 ./foo$(EXEEXT)
This way, foo.1 will not get rebuilt every time
foo$(EXEEXT) changes. The make call makes sure
foo$(EXEEXT) is up-to-date before help2man. Another
way to ensure this would be to use separate directories for binaries
and man pages, and set SUBDIRS so that binaries are built
before man pages.
We could also decide not to distribute foo.1. In this case it's fine to have foo.1 dependent upon foo$(EXEEXT), since both will have to be rebuilt. However it would be impossible to build the package in a cross-compilation, because building foo.1 involves an execution of foo$(EXEEXT).
Another context where such errors are common is when distributed files are built by tools which are built by the package. The pattern is similar:
distributed-file: built-tools distributed-sources
build-command
should be changed to
distributed-file: distributed-sources
$(MAKE) $(AM_MAKEFLAGS) built-tools
build-command
or you could choose not to distribute distributed-file, if cross-compilation does not matter.
The points made through these examples are worth a summary:
|
For desperate cases, it's always possible to disable this check by
setting distcleancheck_listfiles as documented in Dist.
Make sure you do understand the reason why make distcheck
complains before you do this. distcleancheck_listfiles is a
way to hide errors, not to fix them. You can always do better.
This happens when per-target compilation flags are used. Object files need to be renamed just in case they would clash with object files compiled from the same sources, but with different flags. Consider the following example.
bin_PROGRAMS = true false
true_SOURCES = generic.c
true_CPPFLAGS = -DEXIT_CODE=0
false_SOURCES = generic.c
false_CPPFLAGS = -DEXIT_CODE=1
Obviously the two programs are built from the same source, but it
would be bad if they shared the same object, because generic.o
cannot be built with both -DEXIT_CODE=0 *and*
-DEXIT_CODE=1. Therefore automake outputs rules to
build two different objects: true-generic.o and
false-generic.o.
automake doesn't actually look whether sources files are shared to decide if it must rename objects. It will just rename all objects of a target as soon as it sees per-target compilation flags are used.
It's OK to share object files when per-target compilation flags are not used. For instance true and false will both use version.o in the following example.
AM_CPPFLAGS = -DVERSION=1.0
bin_PROGRAMS = true false
true_SOURCES = true.c version.c
false_SOURCES = false.c version.c
Note that the renaming of objects is also affected by the
_SHORTNAME variable (see Program and Library Variables).
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If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this:
with the Invariant Sections being list their titles, with
the Front-Cover Texts being list, and with the Back-Cover Texts
being list.
If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.
If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.
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--gnu and --gnits
--cygnus
[1] These variables are also called make macros in Make terminology, however in this manual we reserve the term macro for Autoconf's macros.
[2] Older Autoconf versions used configure.in. Autoconf 2.50 and greater promotes configure.ac over configure.in. The rest of this documentation will refer to configure.ac, but Automake also supports configure.in for backward compatibility.
[3] Don't try seeking a solution where opt/Makefile is created conditionally, this is a lot trickier than the solutions presented here.
[4] We believe. This work is new and there are probably warts. See Introduction, for information on reporting bugs.
[5] There are other, more obscure reasons reasons for this limitation as well.
[6] Much, if not most, of the information in the following sections pertaining to preprocessing Fortran 77 programs was taken almost verbatim from Catalogue of Rules (The GNU Make Manual).
[7] For example,
the cfortran package
addresses all of these inter-language issues, and runs under nearly all
Fortran 77, C and C++ compilers on nearly all platforms. However,
cfortran is not yet Free Software, but it will be in the next
major release.
[8] See http://sources.redhat.com/automake/dependencies.html for more information on the history and experiences with automatic dependency tracking in Automake
[9] However, for the case of a
non-installed header file that is actually used by a particular program,
we recommend listing it in the program's _SOURCES variable
instead of in noinst_HEADERS. We believe this is more clear.