--gnu and --gnits
--cygnus
Automake is a tool for automatically generating `Makefile.in's from
files called `Makefile.am'. Each `Makefile.am' is basically a
series of make macro definitions (with rules being thrown in
occasionally). The generated `Makefile.in's are compliant with the
GNU Makefile standards.
The GNU Makefile Standards Document (see section `Makefile Conventions' in 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 macro 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 section `Introduction' in The Autoconf Manual), and enforces certain restrictions on the `configure.in' contents(1).
Automake requires perl in order to generate the
`Makefile.in's. 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 macros and targets defined in the `Makefile.am' instruct Automake to generate more specialized code; for instance, a `bin_PROGRAMS' macro definition will cause targets for compiling and linking programs to be generated.
The macro definitions and targets 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 cvs-dist target, which the
Automake maintainer uses to make distributions from his source control
system.
Note that GNU make extensions are not recognized by Automake. Using such extensions in a `Makefile.am' will lead to errors or confusing behavior.
Automake tries to group comments with adjoining targets and macro definitions in an intelligent way.
A target defined in `Makefile.am' generally overrides any such
target 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 macro defined in `Makefile.am' will override any
definition of the macro that automake would ordinarily create.
This feature is more often useful than the ability to override a target
definition. Be warned that many of the macros generated by
automake are considered to be for internal use only, and their
names might change in future releases.
When examining a macro definition, Automake will recursively examine
macros 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 section The effect of --gnu and --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 section The effect of --cygnus.
Automake macros (from here on referred to as 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 section `Directory Variables' in 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, until HTML support 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 not be installed at all.
The special prefix `check' indicates that the objects in question
should not be built until the make check command is run.
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.
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 macro naming rules. All characters in the name except for letters, numbers, the strudel (@), and the underscore are turned into underscores when making macro references.
For example, if your program is named sniff-glue, the derived
variable name would be sniff_glue_SOURCES, not
sniff-glue_SOURCES.
The strudel is an addition, to make the use of Autoconf substitutions in macro 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 -- they don't
have to introduce a second variable into every target.
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.c
ansi2knr.1
compile
config.guess
config.sub
depcomp
elisp-comp
install-sh
install program which works on
platforms where install is unavailable or unusable.
mdate-sh
missing
missing
prints an informative warning and attempts to fix things so that the
build can continue.
mkinstalldirs
mkdir -p is not portable.
py-compile
texinfo.tex
make dvi to work when
Texinfo sources are in the package.
ylwrap
lex 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.in's have been
ad-hoc. You want to make them bulletproof, so you turn to Automake.
The first step is to update your `configure.in' to include the
commands that automake needs. The way to do this is to add an
AM_INIT_AUTOMAKE call just after AC_INIT:
AM_INIT_AUTOMAKE(zardoz, 1.0)
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... 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. Additionally, zardoz has some
Texinfo documentation. Your `configure.in' 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.in' from GNU Hello:
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.
In `doc/Makefile.am' we see:
info_TEXINFOS = hello.texi hello_TEXINFOS = gpl.texi
This is sufficient to build, install, and distribute the GNU Hello manual.
Here is `tests/Makefile.am':
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 (ctags and etags) from the same source file
(`etags.c'). The difficult part is that each compilation of
`etags.c' requires different cpp flags.
bin_PROGRAMS = etags ctags
ctags_SOURCES =
ctags_LDADD = ctags.o
etags.o: etags.c
$(COMPILE) -DETAGS_REGEXPS -c etags.c
ctags.o: etags.c
$(COMPILE) -DCTAGS -o ctags.o -c etags.c
Note that ctags_SOURCES is defined to be empty--that way no
implicit value is substituted. The implicit value, however, is used to
generate etags from `etags.o'.
ctags_LDADD is used to get `ctags.o' into the link line.
ctags_DEPENDENCIES is generated by Automake.
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):
etags.o: etags.c ctags.o
$(COMPILE) -DETAGS_REGEXPS -c etags.c
ctags.o: etags.c
$(COMPILE) -DCTAGS -c etags.c && mv etags.o ctags.o
Also, these explicit rules do not work if the de-ANSI-fication feature is used (see section Automatic de-ANSI-fication). Supporting de-ANSI-fication requires a little more work:
etags._o: etags._c ctags.o
$(COMPILE) -DETAGS_REGEXPS -c etags.c
ctags._o: etags._c
$(COMPILE) -DCTAGS -c etags.c && mv etags._o ctags.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 etags and
ctags in real life, you would probably use per-program
compilation flags, like so:
bin_PROGRAMS = ctags etags ctags_SOURCES = etags.c ctags_CFLAGS = -DCTAGS etags_SOURCES = etags.c etags_CFLAGS = -DETAGS_REGEXPS
In this case Automake will cause `etags.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 `ctags-etags.c' and `etags-etags.o'. (The name of the object files rarely matters.)
To create all the `Makefile.in's 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.in'; see section Scanning `configure.in')
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.in', at
the top. If your package has multiple `configure.in's, then you
must run automake in each directory holding a
`configure.in'.
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.in', and
because automake uses the knowledge that a `Makefile.in' is
in a subdirectory to change its behavior in some cases.
automake accepts the following options:
AC_CANONICAL_HOST. Automake is distributed with several of these
files; 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.
--add-missing, causes installed files to be
copied. The default is to make a symbolic link.
--cygnus.
--add-missing, causes standard files to be rebuilt
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).
--gnu and --gnits.
--gnu and --gnits. This is the default strictness.
automake creates all `Makefile.in's mentioned in
`configure.in'. This option causes it to only update those
`Makefile.in's which are out of date with respect to one of their
dependents.
automake to
become errors. Errors affect the exit status of automake, while
warnings do not. `--Wno-error', the default, causes warnings to be
treated as warnings only.
Automake scans the package's `configure.in' to determine certain
information about the package. Some autoconf macros are required
and some variables must be defined in `configure.in'. Automake
will also use information from `configure.in' 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.in'
call AM_INIT_AUTOMAKE. This macro does several things which are
required for proper Automake operation.
Here are the other macros which Automake requires but which are not run
by AM_INIT_AUTOMAKE:
AC_OUTPUT
Makefile are treated as `Makefile's. Other listed
files are treated differently. Currently the only difference is that a
`Makefile' is removed by make distclean, while other files
are removed by make clean.
You may need the following macros in some conditions, even though they are not required.
AC_CHECK_TOOL([STRIP],[strip])
strip when you run
make install-strip. However strip might not be the
right tool to use in cross-compilation environments, therefore
Automake will honor the STRIP environment variable to overrule
the program used to perform stripping. Automake will not set STRIP
itself. If your package is not setup for cross-compilation you do not
have to care (strip is ok), otherwise you can set STRIP
automatically by calling AC_CHECK_TOOL([STRIP],[strip]) from
your `configure.in'.
Automake will also recognize the use of certain macros and tailor the generated `Makefile.in' appropriately. Currently recognized macros and their effects are:
AC_CONFIG_HEADER
AM_CONFIG_HEADER, which is similar
to AC_CONFIG_HEADER (see section `Configuration Header Files' in The Autoconf Manual), but does
some useful Automake-specific work.
AC_CONFIG_AUX_DIR
AC_PATH_XTRA
AC_PATH_XTRA into each `Makefile.in' that builds a C program
or library. See section `System Services' in The Autoconf Manual.
AC_CANONICAL_HOST
AC_CHECK_TOOL
AC_CANONICAL_SYSTEM
AC_CANONICAL_HOST, but also defines the
`Makefile' variables `build_alias' and `target_alias'.
See section `Getting the Canonical System Type' in The Autoconf Manual.
AC_FUNC_ALLOCA
AC_FUNC_GETLOADAVG
AC_FUNC_MEMCMP
AC_STRUCT_ST_BLOCKS
AC_FUNC_FNMATCH
AC_FUNC_MKTIME
AM_FUNC_STRTOD
AC_REPLACE_FUNCS
AC_REPLACE_GNU_GETOPT
AM_WITH_REGEX
automake -a will not install the sources.
See section Building a library, for more information. Also, see section `Particular Function Checks' in The Autoconf Manual.
LIBOBJS
LIBOBJS, and will treat these additional files as if they were
discovered via AC_REPLACE_FUNCS. See section `Generic Function Checks' in The Autoconf Manual.
AC_PROG_RANLIB
AC_PROG_CXX
AC_PROG_F77
AC_F77_LIBRARY_LDFLAGS
AC_PROG_LIBTOOL
libtool (see section `Introduction' in The Libtool Manual).
AC_PROG_YACC
AC_DECL_YYTEXT
AC_PROG_LEX
AM_C_PROTOTYPES
AM_GNU_GETTEXT
AM_MAINTAINER_MODE
configure. If this is used, automake will cause
`maintainer-only' rules to be turned off by default in the
generated `Makefile.in's. This macro is disallowed in `Gnits'
mode (see section The effect of --gnu and --gnits). This macro defines the `MAINTAINER_MODE'
conditional, which you can use in your own `Makefile.am'.
AC_SUBST
AC_CHECK_TOOL
AC_CHECK_PROG
AC_CHECK_PROGS
AC_PATH_PROG
AC_PATH_PROGS
Automake includes a number of Autoconf macros which can be used in your
package; 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.in'. This provides a
convenient way to get Automake-provided macros, without having to
search around. Also, the aclocal mechanism is extensible for use
by other packages.
At startup, aclocal scans all the `.m4' files it can find,
looking for macro definitions. Then it scans `configure.in'. 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'.
The contents of `acinclude.m4', if it exists, are also automatically included in `aclocal.m4'. This is useful for incorporating local macros into `configure'.
aclocal tries to be smart about looking for new AC_DEFUNs
in the files it scans. It will warn if it finds duplicates. It also
tries to copy the full text of the scanned file into `aclocal.m4',
including both `#' and `dnl' comments. If you want to make a
comment which will be completely ignored by aclocal, use
`##' as the comment leader.
aclocal accepts the following options:
--acdir=dir
--help
-I dir
--output=file
--print-ac-dir
aclocal will search to
find the `.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
--version
AM_CONFIG_HEADER
AM_ENABLE_MULTILIB
_AM_DEPENDENCIES
AM_SET_DEPDIR
AM_DEP_TRACK
AM_OUTPUT_DEPENDENCY_COMMANDS
AM_FUNC_STRTOD
strtod function is not available, or does not work
correctly (like the one on SunOS 5.4), add `strtod.o' to output
variable LIBOBJS.
AM_FUNC_ERROR_AT_LINE
error_at_line is not found, then add
`error.o' to LIBOBJS.
AM_FUNC_OBSTACK
AM_C_PROTOTYPES
AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL
TIOCGWINSZ requires `<sys/ioctl.h>', then
define GWINSZ_IN_SYS_IOCTL. Otherwise TIOCGWINSZ can be
found in `<termios.h>'.
AM_INIT_AUTOMAKE
AC_DEFINE's `PACKAGE' and `VERSION'. This
can be avoided by passing in a non-empty third argument.
AM_MAKE_INCLUDE
make handles
include statements. This macro is automatically invoked when
needed; there should be no need to invoke it manually.
AM_PATH_LISPDIR
emacs, and, if found, sets the output
variable lispdir to the full path to Emacs' site-lisp directory.
AM_PROG_AS
ASFLAGS if required.
AM_PROG_CC_C_O
AC_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_CC_STDC
CC to make it so. This macro tries various
options that select ANSI C on some system or another. It considers the
compiler to be in ANSI C mode if it handles function prototypes correctly.
If you use this macro, you should check after calling it whether the C
compiler has been set to accept ANSI C; if not, the shell variable
am_cv_prog_cc_stdc is set to `no'. If you wrote your source
code in ANSI C, you can make an un-ANSIfied copy of it by using the
ansi2knr option (see section Automatic de-ANSI-fication).
AM_PROG_LEX
AC_PROG_LEX with AC_DECL_YYTEXT (see section `Particular Program Checks' in The Autoconf Manual),
but uses the missing script on systems that do not have
lex. `HP-UX 10' is one such system.
Autoconf 2.50 and higher, in order to simplify the interface, includes
the body of AC_DECL_YYTEXT in AC_PROG_LEX. To ensure
backward compatibility, AC_DECL_YYTEXT is nevertheless defined as
an invocation of AC_PROG_LEX. Since AM_PROG_LEX invokes
both, it causes an annoying but benign warning (AC_PROG_LEX
invoked multiple times) which you should just ignore. In the future,
once Automake requires Autoconf 2.50, this issue will be fixed, but the
current compatibility with Autoconf 2.13 prevents this.
AM_PROG_GCJ
gcj program or causes an error. It sets
`GCJ' and `GCJFLAGS'. gcj is the Java front-end to the
GNU Compiler Collection.
AM_PROG_INSTALL_STRIP
install which can be used to
strip a program at installation time. This macro is
automatically included when required.
AM_SANITY_CHECK
AM_INIT_AUTOMAKE.
AM_SYS_POSIX_TERMIOS
am_cv_sys_posix_termios to
`yes'. If not, set the variable to `no'.
AM_TYPE_PTRDIFF_T
AM_WITH_DMALLOC
WITH_DMALLOC and add `-ldmalloc' to LIBS.
AM_WITH_REGEX
configure 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 aclocal program doesn't have any built-in knowledge of any
macros, so it is easy to extend it with your own macros.
This is mostly used for 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 file of macros should be a series of AC_DEFUN's. The
aclocal programs also understands AC_REQUIRE, so it is
safe to put each macro in a separate file. See section `Prerequisite Macros' in The Autoconf Manual, and section `Macro Definitions' in The Autoconf Manual.
A macro file's name should end in `.m4'. Such files should be installed in `$(datadir)/aclocal'.
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 macro holds a list of subdirectories in which
building of various sorts can occur. Many targets (e.g. all) in
the generated `Makefile' will run both locally and in all specified
subdirectories. Note that the directories listed in SUBDIRS are
not required to contain `Makefile.am's; only `Makefile's
(after configuration). This allows inclusion of libraries from packages
which do not use Automake (such as gettext). The directories
mentioned in SUBDIRS must be direct children of the current
directory. For instance, you cannot put `src/subdir' into
SUBDIRS.
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
It is possible to override the SUBDIRS variable if, like in the
case of GNU Inetutils, you want to only build a subset of the
entire package. In your `Makefile.am' include:
SUBDIRS = @MY_SUBDIRS@
Then in your `configure.in' you can specify:
MY_SUBDIRS="src doc lib po" AC_SUBST(MY_SUBDIRS)
(Note that we don't use the variable name SUBDIRS in our
`configure.in'; that would cause Automake to believe that every
`Makefile.in' should recurse into the listed subdirectories.)
The upshot of this is that Automake is tricked into building the package
to take the subdirs, but doesn't actually bind that list until
configure is run.
Although the SUBDIRS macro can contain configure substitutions
(e.g. `@DIRS@'); Automake itself does not actually examine the
contents of this variable.
If SUBDIRS is defined, then your `configure.in' must include
AC_PROG_MAKE_SET. 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 use of SUBDIRS is not restricted to just the top-level
`Makefile.am'. Automake can be used to construct packages of
arbitrary depth.
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' targets are run in reverse order of build
targets.
Sometimes, such as when running make dist, you want all possible
subdirectories to be examined. In this case Automake will use
DIST_SUBDIRS, instead of SUBDIRS, to determine where to
recurse. This variable will also be used when the user runs
distclean or maintainer-clean. It should be set to the
full list of subdirectories in the project. If this macro is not set,
Automake will attempt to set it for you.
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 (2) 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
Automake generates rules to automatically rebuild `Makefile's, `configure', and other derived files like `Makefile.in'.
If you are using AM_MAINTAINER_MODE in `configure.in', 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 macro
is only useful in the top-level `Makefile.am'.
A large part of Automake's functionality is dedicated to making it easy to build programs and libraries.
In a directory containing source that gets built into a program (as
opposed to a library), 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'; that is, the default is to compile a single C file whose base name is the name of the program itself. (This is a terrible default but we are stuck with it for historical reasons.)
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 section Yacc and Lex support.
You can't put a configure substitution (e.g., `@FOO@') 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.
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' were conditionally included in hello, the
`Makefile.am' would contain:
EXTRA_hello_SOURCES = hello-linux.c
In this case, `hello-linux.o' would be added, via a
`configure' substitution, to hello_LDADD in order to cause
it 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 construct to conditionally use `hello-linux.c' or `hello-generic.c' as the basis for your program `hello':
if LINUX hello_SOURCES = hello-linux.c else hello_SOURCES = hello-generic.c endif
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.
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.
In 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.
Of course you can use Automake conditionals to determine the programs to be built.
If you need to link against libraries that are not found by
configure, you can use LDADD to do so. This variable
actually can be used to add any options to the linker command line.
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.
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 section Building 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 section How derived variables are named), 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 section Built sources).
Building shared libraries is a relatively complex matter. For this reason, GNU Libtool (see section `Introduction' in The Libtool Manual) was created to help build shared libraries in a platform-independent way.
Automake uses Libtool to build libraries declared with the `LTLIBRARIES' primary. Each `_LTLIBRARIES' variable is a list of shared libraries to build. For instance, to create a library named `libgettext.a' and its corresponding shared libraries, and install them in `libdir', write:
lib_LTLIBRARIES = libgettext.la
Note that shared libraries must be installed, so
check_LTLIBRARIES is not allowed. However,
noinst_LTLIBRARIES is allowed. This feature should be used for
libtool "convenience libraries".
For each library, the `library_LIBADD' variable contains the names of extra libtool objects (`.lo' files) to add to the shared library. The `library_LDFLAGS' variable contains any additional libtool flags, such as `-version-info' or `-static'.
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'. The libtool manual contains more details on this topic.
For libraries installed in some directory, Automake will automatically
supply the appropriate `-rpath' option. However, for libraries
determined at configure time (and thus mentioned in
EXTRA_LTLIBRARIES), Automake does not know the eventual
installation directory; for such libraries you must add the
`-rpath' option to the appropriate `_LDFLAGS' variable by
hand.
Ordinarily, Automake requires that a shared library's name start with
`lib'. However, if you are building a dynamically loadable module
then you might wish to use a "nonstandard" name. In this case, put
-module into the `_LDFLAGS' variable.
See section `The Libtool Manual' in The Libtool Manual, for more information.
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.
nodist_maude_SOURCES = nodist.c dist_maude_SOURCES = dist-me.cBy 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 section Changing Automake's Behavior).
$(AR) cru
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 macro set
like so:
libmaude_a_AR = $(CXX) -ar -o
configure. Note that `_LIBADD' is not used for shared
libraries; there you must use `_LDADD'.
configure.
`_LDADD' is 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.in' 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)
maude_LINK = $(CCLD) -magic -o $@
maude_CFLAGS = ... your flags ... $(AM_CFLAGS)
Automake explicitly recognizes the use of @LIBOBJS@ and
@ALLOCA@, and uses this information, plus the list of
LIBOBJS files derived from `configure.in' to automatically
include the appropriate source files in the distribution (see section What Goes in a Distribution).
These source files are also automatically handled in the
dependency-tracking scheme; see See section Automatic dependency tracking.
@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_CPPFLAGS
AC_CONFIG_HEADER or AM_CONFIG_HEADER). You can disable
the default `-I' options using the `nostdinc' option.
INCLUDES
AM_CFLAGS
CFLAGS.
COMPILE
LINK
CFLAGS); 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.in' must
define the variable `YACC'. This is most easily done by invoking
the macro `AC_PROG_YACC' (see section `Particular Program Checks' in 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.
Similarly, if a lex source file is seen, then your
`configure.in' must define the variable `LEX'. You can use
`AC_PROG_LEX' to do this (see section `Particular Program Checks' in The Autoconf Manual). Automake's lex
support also requires that you use the `AC_DECL_YYTEXT'
macro--automake needs to know the value of `LEX_OUTPUT_ROOT'.
This is all handled for you if you use the AM_PROG_LEX macro
(see section Autoconf macros supplied with Automake).
When yacc 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. 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 section `Finding `configure' Input' in The Autoconf Manual), or the current directory if that macro
is not used in `configure.in'.
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.in'; the simplest way to do this is to use
the AC_PROG_CXX macro (see section `Particular Program Checks' in The Autoconf Manual).
A few additional variables are defined when a C++ source file is seen:
CXX
CXXFLAGS
AM_CXXFLAGS
CXXFLAGS.
CXXCOMPILE
CXXLINK
Automake includes some support for assembly code.
The variable AS 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
ASFLAGS is passed to the compilation.
You are required to set AS and ASFLAGS via
`configure.in'. The autoconf macro AM_PROG_AS will do this
for you. Unless they are already set, it simply sets AS to the C
compiler and ASFLAGS to the C compiler flags.
Automake includes full support for Fortran 77.
Any package including Fortran 77 code must define the output variable
`F77' in `configure.in'; the simplest way to do this is to use
the AC_PROG_F77 macro (see section `Particular Program Checks' in The Autoconf Manual). See section Fortran 77 and Autoconf.
A few additional variables are defined when a Fortran 77 source file is seen:
F77
FFLAGS
AM_FFLAGS
FFLAGS.
RFLAGS
AM_RFLAGS
RFLAGS.
F77COMPILE
FLINK
Automake can handle preprocessing Fortran 77 and Ratfor source files in addition to compiling them(4). Automake also contains some support for creating programs and shared libraries that are a mixture of Fortran 77 and other languages (see section 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 packages(5).
Automake can help in two ways:
FLIBS by the AC_F77_LIBRARY_LDFLAGS Autoconf macro
supplied with newer versions of Autoconf (Autoconf version 2.13 and
later). See section `Fortran 77 Compiler Characteristics' in 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.in', and that either $(FLIBS) or @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)
or @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.in'. 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 | |
| | | |
+---------+---------+---------+
The current Automake support for Fortran 77 requires a recent enough version Autoconf that also includes support for Fortran 77. Full Fortran 77 support was added to Autoconf 2.13, so you will want to use that version of Autoconf or later.
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.in'; the variable `GCJFLAGS'
must also be defined somehow (either in `configure.in' 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 macro, and not the
user macro `GCJFLAGS', should be used.
gcj can be used to compile `.java', `.class',
`.zip', or `.jar' files.
Automake currently only includes full support for C, C++ (see section C++ Support), Fortran 77 (see section Fortran 77 Support), and Java (see section 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 section Handling new file extensions.
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 section Changing Automake's Behavior) 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.in' must call the macro AM_C_PROTOTYPES
(see section Autoconf macros supplied with Automake).
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' subdirs. 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.
Files mentioned in LIBOBJS which need de-ANSI-fication will not
be automatically handled. That's because configure will generate
an object name like `regex.o', while make will be looking
for `regex_.o' (when de-ANSI-fying). Eventually this problem will
be fixed via autoconf magic, but for now you must put this code
into your `configure.in', just before the AC_OUTPUT call:
# This is necessary so that .o files in LIBOBJS are also built via # the ANSI2KNR-filtering rules. LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
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.
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 (6) 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, 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 the support isn't completely transparent; if you want your package to support these platforms then you must assist.
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.in' must
take care to add `$(EXEEXT)' when constructing the output variable.
With Autoconf 2.13 and earlier, you must explicitly use AC_EXEEXT
to get this support. With Autoconf 2.50, AC_EXEEXT is run
automatically if you configure a compiler (say, through
AC_PROG_CC).
Sometimes maintainers like to write an explicit link rule for their program. Without executable extension support, this is easy--you simply write a target with the same name as the program. However, when executable extension support is enabled, you must instead add the `$(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 section Changing Automake's Behavior) will disable this feature. This works in a fairly
ugly way; if no-exeext is seen, then the presence of a target
named foo in `Makefile.am' will override an
automake-generated target of the form foo$(EXEEXT). Without the
no-exeext option, this use will give an error.
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 section What Gets Cleaned).
The automake program itself is a Perl script that is generated at
configure time from `automake.in'. Here is how this is handled:
bin_SCRIPTS = automake
Since automake appears in the AC_OUTPUT macro, a target
for it is automatically generated.
Script objects can be installed in bindir, sbindir,
libexecdir, or pkgdatadir.
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. (7)
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 section Building 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 installs its auxiliary data files:
pkgdata_DATA = clean-kr.am clean.am ...
Occasionally a file which would otherwise be called `source'
(e.g. a C `.h' file) is actually derived from some other file.
Such files should be listed in the BUILT_SOURCES variable.
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.
A source file listed in BUILT_SOURCES is created before the other
all targets are made. However, such a source file is not
compiled unless explicitly requested by mentioning it in some other
`_SOURCES' variable.
So, for instance, if you had header files which were created by a script
run at build time, then you would list these headers in
BUILT_SOURCES, to ensure that they would be built before any
other compilations (perhaps ones using these headers) were started.
Since Automake is primarily intended to generate `Makefile.in's 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.in' must run
AM_PATH_LISPDIR (see section Autoconf macros supplied with Automake).
By default Automake will byte-compile all Emacs Lisp source files using
the Emacs found by AM_PATH_LISPDIR. If you wish to avoid
byte-compiling, simply define the variable ELCFILES to be empty.
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 leave it enabled by default. It is probably better for sites with
strange setups to cope for themselves than to make the installation less
nice for everybody else.
If AM_GNU_GETTEXT is seen in `configure.in', then Automake
turns on support for GNU gettext, a message catalog system for
internationalization
(see section `GNU Gettext' in 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.
Automake provides support for GNU Libtool (see section `Introduction' in The Libtool Manual) with the `LTLIBRARIES' primary. See section Building 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:
JAVAC
JAVACFLAGS
AM_JAVACFLAGS
JAVACFLAGS, should be used when it is necessary to put Java
compiler flags into `Makefile.am'.
JAVAROOT
javac. It defaults to `$(top_builddir)'.
CLASSPATH_ENV
sh 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 modules. Automake will turn on
Python support if the AM_PATH_PYTHON macro is used in
`configure.in'. The `PYTHON' primary is used to hold a list
of `.py' files. Possible prefixes for this primary are
`python_' and `noinst_'. Note that if python_PYTHON is
defined, then `configure.in' must run AM_PATH_PYTHON.
Python source files are included in the distribution by default.
AM_PATH_PYTHON takes a single optional argument. This argument,
if present, is the minimum version of Python which can be used for this
package. If the version of Python found on the system is older than the
required version, then AM_PATH_PYTHON will cause an error.
AM_PATH_PYTHON creates several output variables based on the
Python installation found during configuration.
PYTHON
PYTHON_VERSION
sys.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
$exec_prefix. This term may be used in future work
which needs the contents of Python's sys.exec_prefix, but general
consensus is to always use the value from configure.
PYTHON_PLATFORM
sys.platform. This value is sometimes needed when
building Python extensions.
pythondir
pkgpythondir
pythondir which is named after the
package. That is, it is `$(pythondir)/$(PACKAGE)'. It is provided
as a convenience.
pyexecdir
pkgpyexecdir
By default Automake will byte-compile all Python source files to both
`.pyc' and `.pyo' forms. If you wish to avoid generating the
optimized byte-code files, simply define the variable PYOFILES to
be empty. Similarly, if you don't wish to generate the standard
byte-compiled files, define the variable PYCFILES to be empty.
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 macro is most commonly used
here. Any Texinfo source file must end in the `.texi',
`.txi', or `.texinfo' extension. We recommend `.texi'
for new manuals.
If the `.texi' file @includes `version.texi', then
that file will be automatically generated. The file `version.texi'
defines four Texinfo macros you can reference:
EDITION
VERSION
UPDATED
UPDATED-MONTH
The `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.
When an info file is rebuilt, the program named by the MAKEINFO
variable is used to invoke it. If the makeinfo program is found
on the system then it will be used by default; otherwise missing
will be used instead. The flags in the variables MAKEINFOFLAGS
and AM_MAKEINFOFLAGS will be passed to the makeinfo
invocation; the first of these is intended for use by the user
(see section Variables reserved for the user) and the second by the `Makefile.am'
writer.
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. However, if you used
AC_CONFIG_AUX_DIR in `configure.in' (see section `Finding `configure' Input' in The Autoconf Manual), then
`texinfo.tex' is looked for there. Automake supplies
`texinfo.tex' if `--add-missing' is given.
If your package has Texinfo files in many directories, you can use the
variable TEXINFO_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
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 target to still work.
Automake generates an install-info target; some people apparently
use this. By default, info pages are installed by `make install'.
This can be prevented via the no-installinfo option.
A package can also include man pages (but see the GNU standards on this
matter, section `Man Pages' in The GNU Coding Standards.) Man
pages are declared using the `MANS' primary. Generally the
man_MANS macro 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
targets, 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 target. If these
targets 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 section `Makefile Conventions' in 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 repsect `DESTDIR'.
Automake also generates an uninstall target, an
installdirs target, and an install-strip target.
Automake supports uninstall-local and uninstall-hook.
There is no notion of separate uninstalls for "exec" and "data", as
that does not make sense.
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.
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 target, we've adopted a heuristic which we believe was first formulated by Fran@,{c}ois 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.
We recommend that you follow this same set of heuristics in your `Makefile.am'.
The dist target in the generated `Makefile.in' can be used
to generate a gzip'd tar file for distribution. The tar file is
named based on the `PACKAGE' and `VERSION' variables; more
precisely it 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.am's and `Makefile.in's. Automake also
has a built-in list of commonly used files which, if present in the
current directory, are automatically included. 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 the
AC_OUTPUT invocation) are automatically 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.
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
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`
If you define SUBDIRS, Automake will recursively include the
subdirectories in the distribution. If SUBDIRS is defined
conditionally (see section 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.
Occasionally it is useful to be able to change the distribution before
it is packaged up. If the dist-hook target 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
Automake also generates a distcheck target which can be of help
to ensure that a given distribution will actually work.
distcheck makes a distribution, and then tries to do a
VPATH build.
If the target distcheck-hook 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.
By default Automake generates a `.tar.gz' file when asked to create a distribution. However, some projects prefer different packaging formats. Automake accomodates most of these using options; section Changing Automake's Behavior.
Automake also generates a dist-all target which can be used to
make all the requested packaged distributions at once.
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 section `Build Directories' in The Autoconf Manual), and in particular for the distcheck target
(see section What Goes in a Distribution).
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 section Variables reserved for the user). If you need to set runtest flags in
`Makefile.am', you can use AM_RUNTESTFLAGS instead.
In either case, the testing is done via `make check'.
Various features of Automake can be controlled by options in the
`Makefile.am'. Such options are listed in a special variable named
AUTOMAKE_OPTIONS. Currently understood options are:
gnits
gnu
foreign
cygnus
gnits option also implies
readme-alpha and check-news.
ansi2knr
path/ansi2knr
check-news
make dist to fail unless the current version number appears
in the first few lines of the `NEWS' file.
dejagnu
dejagnu-specific rules to be generated. See section Support for test suites.
dist-bzip2
dist-bzip2 target as well as the ordinary dist
target. This new target will create a bzip2 tar archive of the
distribution. bzip2 archives are frequently smaller than even gzipped
archives.
dist-shar
dist-shar target as well as the ordinary dist
target. This new target will create a shar archive of the
distribution.
dist-zip
dist-zip target as well as the ordinary dist
target. This new target will create a zip archive of the distribution.
dist-tarZ
dist-tarZ target as well as the ordinary dist
target. This new target will create a compressed tar archive of the
distribution.
no-dependencies
no-exeext
EXEEXT 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-installinfo
info and install-info
targets will still be available. This option is disallowed at
`GNU' strictness and above.
no-installman
install-man target will still
be available for optional installation. This option is disallowed at
`GNU' strictness and above.
nostdinc
no-texinfo.tex
readme-alpha
subdir-objects
Unrecognized options are diagnosed by automake.
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 targets will be generated for the directory.
At the topmost directory of a multi-directory package, a tags
target file will be generated which, when run, will generate a
`TAGS' file that includes by reference all `TAGS' files from
subdirectories.
The tags target 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.
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 target.
Automake will also generate an ID target 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 target 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. If this is done, you must
notify GNU Make of the new suffixes. This can be done by putting a list
of new suffixes in the SUFFIXES variable.
For instance, suppose you had a compiler which could compile `.foo' files to `.o' files. Then you would add `.foo' to your suffix list:
SUFFIXES = .foo
Then you could directly use a `.foo' file in a `_SOURCES' variable and expect the correct results:
bin_PROGRAMS = doit doit_SOURCES = doit.foo
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)/file
include $(top_srcdir)/file
Note that if a fragment is included inside a conditional, then the condition applies to the entire contents of that fragment.
Automake supports a simple type of conditionals.
Before using a conditional, you must define it by using
AM_CONDITIONAL in the configure.in file (see section Autoconf macros supplied with Automake).
The shell condition (suitable for use in a shell if
statement) is evaluated when configure is run. Note that you
must arrange for every AM_CONDITIONAL to be invoked every
time configure is run -- if AM_CONDITIONAL is run
conditionally (e.g., in a shell if statement), then the result
will confuse automake.
Conditionals typically depend upon options which the user provides to
the configure script. Here is an example of how to write a
conditional which is true if the user uses the `--enable-debug'
option.
AC_ARG_ENABLE(debug,
[ --enable-debug Turn on debugging],
[case "${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 section Building a program).
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
targets; 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:
--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.
Automake's implicit copying semantics means that many problems can be
worked around by simply adding some make targets and rules to
`Makefile.in'. Automake will ignore these additions.
There are some caveats to doing this. Although you can overload a target already used by Automake, it is often inadvisable, particularly in the topmost directory of a package with subdirectories. 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, check, install-data, install-exec,
uninstall, 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 /etc/afile
Some targets also have a way to run another target, 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, dist, and
distcheck.
For instance, here is how to create a hard link to an installed program:
install-exec-hook:
ln $(bindir)/program $(bindir)/proglink
Automake places no restrictions on the distribution of the resulting `Makefile.in's. 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.
Autoconf 2.50 promotes `configure.ac' over `configure.in'. The rest of this documentation will refer to `configure.in' as this use is not yet spread, but Automake supports `configure.ac' too.
We believe. This work is new and there are probably warts. See section Introduction, for information on reporting bugs.
There are other, more obscure reasons reasons for this limitation as well.
Much, if not most, of the information in the following sections pertaining to preprocessing Fortran 77 programs was taken almost verbatim from section `Catalogue of Rules' in The GNU Make Manual.
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.
See http://sources.redhat.com/automake/dependencies.html for more information on the history and experiences with automatic dependency tracking in Automake
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.
This document was generated on 7 October 2001 using the texi2html translator version 1.54.