     [file version.texi not included]

This file documents GNU automake VERSION

Copyright (C) 1995 Free Software Foundation, Inc.

Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.

Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation.

GNU Automake
************

This file documents the GNU Automake package for creating GNU Standards-compliant Makefiles from template files.  This edition documents version VERSION.

Introduction
************

Automake is a tool for automatically generating Makefile.ins from files called Makefile.am.  The Makefile.am is basically a series of make macro definitions (with rules being thrown in occasionally).  The generated Makefile.ins are compliant with the GNU Makefile standards.

The GNU Makefile Standards Document (see Makefile Conventions (The GNU Coding Standards)) is long, complicated, and subject to change.  The goal of Automake is to remove the burden of Makefile maintenance from the back of the individual GNU maintainer (and put it on the back of the Automake maintainer).

The typical Automake input files 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 The Autoconf Manual), and enforces certain restrictions on the configure.in contents.

Automake requires perl in order to generate the Makefile.ins.  However, the distributions created by Automake are fully GNU standards-compliant, and do not require perl in order to be built.

Mail suggestions and bug reports for Automake to bug-gnu-utils@prep.ai.mit.edu.

Creating a Makefile.in
**********************

To create all the Makefile.ins for a package, run the automake program in the top level directory, with no arguments. automake will automatically find each appropriate Makefile.am (by scanning configure.in; see configure) and generate the corresponding Makefile.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:

-a

--add-missing
     Automake requires certain common files to exist in certain situations; for instance config.guess is required if configure.in runs 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.

--amdir=DIR
     Look for Automake data files in directory DIR instead of in the installation directory.  This is typically used for debugging.

--build-dir=DIR
     Tell Automake where the build directory is.  This option is used when including dependencies into a Makefile.in generated by make dist; it should not be used otherwise.

--foreign
     An alias for --strictness=foreign.

--gnits
     An alias for --strictness=gnits.

--gnu
     An alias for --strictness=gnu.

--help
     Print a summary of the command line options and exit.

-i

--include-deps
     Include all automatically generated dependency information (see Dependencies) in the generated Makefile.in.  This is generally done when making a distribution; see Dist.

-o DIR

--output-dir=DIR
     Put the generated Makefile.in in the directory DIR. Ordinarily each Makefile.in is created in the directory of the corresponding Makefile.am.  This option is used when making distributions.

--srcdir-name=DIR
     Tell Automake the name of the source directory used in the current build.  This option is used when including dependencies into a Makefile.in generated by make dist; it should not be used otherwise.

-s LEVEL

--strictness=LEVEL
     Set the global strictness to LEVEL; this can be overridden in each Makefile.am if required.  See Generalities for more information.

-v

--verbose
     Cause Automake to print information about which files are being read or created.

--version
     Print the version number of Automake and exit.

General ideas
*************

There are a few basic ideas that will help understand how Automake works.

General Operation
=================

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 instances a bin_PROGRAMS macro definition will cause targets for compiling and linking to be generated.

The macro definitions and targets in the Makefile.am are copied 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 (or variable 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 variable defined in Makefile.am will override any definition of the variable 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 variables generated by automake are considered to be for internal use only, and their names might change in future releases.

When examining a variable definition, Automake will recursively examine variables referenced in the definition.  Eg 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 ## 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

Depth
=====

automake supports three kinds of directory hierarchy: ``flat'', ``shallow'', and ``deep''.

A flat package is one in which all the files are in a single directory.  The Makefile.am for such a package by definition lacks a SUBDIRS macro.  An example of such a package is termutils.

A deep package is one in which all the source lies in subdirectories; the top level directory contains mainly configuration information.  GNU cpio is a good example of such a package, as is GNU tar.  The top level Makefile.am for a deep package will contain a SUBDIRS macro, but no other macros to define objects which are built.

A shallow package is one in which the primary source resides in the top-level directory, while various parts (typically libraries) reside in subdirectories.  automake is one such package (as is GNU make, which does not currently use automake).

Strictness
==========

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:

foreign
     Automake will check for only those things which are absolutely required for proper operations.  For instance, whereas GNU standards dictate the existence of a NEWS file, it will not be required in this mode.  The name comes from the fact that Automake is intended to be used for GNU programs; these relaxed rules are not the standard mode of operation.

gnu
     Automake will check -- as much as possible -- for compliance to the GNU standards for packages.  This is the default.

gnits
     Automake will check for compliance to the as-yet-unwritten GNITS standards.  These are based on the GNU standards, but are even more detailed.  Unless you are a GNITS standards contributor, it is recommended that you avoid this option until such time as the GNITS standard is actually published.

For more information on the precise implications of the strictness level, see Gnits.

The Uniform Naming Scheme
=========================

Automake variables generally follow a uniform naming scheme that makes it easy to decide how programs (and other derived objects) are built, and how they are installed.  This scheme also supports configure time determination of what should be built.

At make time, certain variables are used to determine which objects are to be built.  These variables are called primary variables.  For instance, the primary variable PROGRAMS holds a list of programs which are to be compiled and linked.

A different set of variables is used to decide where the built objects should be installed.  These variables are named after the primary variables, but have a prefix indicating which standard directory should be used as the installation directory.  The standard directory names are given in the GNU standards (see Directory Variables (The GNU Coding Standards)). automake extends this list with pkglibdir, pkgincludedir, and pkgdatadir; these are the same as the non-pkg versions, but with @PACKAGE@ appended.

For 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 know the entire list of objects to 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 = @PROGRAMS@

Defining a primary variable 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 (eg zar) is valid if a variable of the same name with dir appended is defined (eg 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.

Possible primary names are PROGRAMS, LIBRARIES, LISP, SCRIPTS, DATA, HEADERS, MANS, and TEXINFOS.

How derived variables are named
===============================

Sometimes a Makefile variable name is derived from some text the user supplies.  For instance program names are rewritten into Makefile macro names.  Automake canonicalizes this text, so that it does not have to follow Makefile variable naming rules.  All characters in the name except for letters, numbers, and the underscore are turned into underscores when making macro references.  Eg, if your program is named sniff-glue, the derived variable name would be sniff_glue_SOURCES, not sniff-glue_SOURCES.

Scanning configure.in
*********************

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.

Configuration requirements
==========================

The simplest way to meet the basic Automake requirements is to use the macro AM_INIT_AUTOMAKE (FIXME: xref).  But if you prefer, you can do the required steps by hand:

  * Define the variables PACKAGE and VERSION with AC_SUBST. PACKAGE should be the name of the package as it appears when bundled for distribution.  For instance, Automake defines PACKAGE to be automake.  VERSION should be the version number of the release that is being developed.  We recommend that you make configure.in the only place in your package where the version number is defined; this makes releases simpler.

     Automake doesn't do any interpretation of PACKAGE or VERSION, except in Gnits mode (FIXME xref).

  * Use the macro AC_ARG_PROGRAM if a program or script is installed.

  * Use AC_PROG_MAKE_SET if the package is not flat.

  * Use AM_PROG_INSTALL if any scripts (see Scripts) are installed by the package.  Otherwise, use AC_PROG_INSTALL.

Here are the other macros which Automake requires but which are not run by AM_INIT_AUTOMAKE:

AC_OUTPUT
     Automake uses this to determine which files to create.  Listed files named Makefile are treated as Makefiles.  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.

Other things Automake recognizes
================================

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
     Automake will generate rules to automatically regenerate the config header.  If you do use this macro, you must create the file stamp-h.in in your source directory.  It can be empty.  Also, the AC_OUTPUT command in configure.in must create stamp-h, eg:

          AC_OUTPUT(Makefile,
          [test -z "$CONFIG_HEADERS" || echo timestamp > stamp-h])

     Note that Automake does not currently currently check to make sure the AC_OUTPUT command is correct.  Hopefully a future version of autoconf will let Automake handle this automatically.

AC_CONFIG_AUX_DIR
     Automake will look for various helper scripts, such as mkinstalldirs, in the directory named in this macro invocation. If not seen, the scripts are looked for in their ``standard'' locations (either the top source directory, or in the source directory corresponding to the current Makefile.am, whichever is appropriate). FIXME: give complete list of things looked for in this directory

AC_PATH_XTRA
     Automake will insert definitions for the variables defined by AC_PATH_XTRA into each Makefile.in that builds a C program or library.

AC_CANONICAL_HOST

AC_CHECK_TOOL
     Automake will ensure that config.guess and config.sub exist.  Also, the Makefile variables host_alias and host_triplet are introduced.

AC_CANONICAL_SYSTEM
     This is similar to AC_CANONICAL_HOST, but also defines the Makefile variables build_alias and target_alias.

AC_FUNC_ALLOCA

AC_FUNC_GETLOADAVG

AC_FUNC_MEMCMP

AC_STRUCT_ST_BLOCKS

AM_FUNC_FNMATCH

AM_FUNC_STRTOD

AC_REPLACE_FUNCS

AC_REPLACE_GNU_GETOPT

AM_WITH_REGEX
     Automake will ensure that the appropriate source files are part of the distribution, and will ensure that the appropriate dependencies are generated for these objects.  See A Library for more information.

LIBOBJS
     Automake will detect statements which put .o files into LIBOBJS, and will treat these additional files as if they were discovered via AC_REPLACE_FUNCS.

AC_PROG_RANLIB
     This is required if any libraries are built in the package.

AC_PROG_CXX
     This is required if any C++ source is included.

AC_PROG_YACC
     If a Yacc source file is seen, then you must either use this macro or declare the variable YACC in configure.in.  The former is preferred.

AC_DECL_YYTEXT
     This macro is required if there is Lex source in the package.

AC_PROG_LEX
     If a Lex source file is seen, then this macro must be used.

ALL_LINGUAS
     If Automake sees that this variable is set in configure.in, it will check the po directory to ensure that all the named .po files exist, and that all the .po files that exist are named.

AM_C_PROTOTYPES
     This is required when using automatic de-ANSI-fication, see ANSI.

ud_GNU_GETTEXT
     This macro is required for packages which use GNU gettext (see gettext).  It is distributed with gettext.  If Automake sees this macro it ensures that the package meets some of gettext's requirements.

AM_MAINTAINER_MODE
     This macro adds a --enable-maintainer-mode option to configure.  If this is used, automake will cause ``maintainer-only'' rules to be turned off by default in the generated Makefile.ins.  This macro is disallowed in Gnits mode. FIXME xref.

Auto-generating aclocal.m4
==========================

The aclocal program will automatically generate aclocal.m4 files based on the contents of configure.in.

... explain why on earth you'd want to do this

aclocal accepts the following options:

--acdir=DIR
     Look for the macro files in DIR instead of the installation directory.  This is typically used for debugging.

--help
     Print a summary of the command line options and exit.

--output=FILE
     Cause the output to be put into FILE instead of aclocal.m4.

--verbose
     Print the names of the files it examines.

--version
     Print the version number of Automake and exit.

Autoconf macros supplied with Automake
======================================

AM_FUNC_FNMATCH
     If the fnmatch function is not available, or does not work correctly (like the one on SunOS 5.4), add fnmatch.o to output variable LIBOBJS.

AM_FUNC_STRTOD
     If the 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

AM_FUNC_MKTIME

AM_FUNC_OBSTACK

AM_C_PROTOTYPES

AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL

AM_INIT_AUTOMAKE

AM_MAINTAINER_MODE

AM_PATH_LISPDIR

AM_PROG_CC_STDC

AM_PROG_INSTALL

AM_SANITY_CHECK_CC

AM_SYS_POSIX_TERMIOS

AM_TYPE_PTRDIFF_T

AM_WITH_DMALLOC

AM_WITH_REGEX

Writing your own aclocal macros
===============================

... explain format of macro files ... explain how to get your own macros installed (using acinstall) ... explain situations where this is actually useful (eg gettext)

The top-level Makefile.am
*************************

In non-flat packages, 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 (eg 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.ams; only Makefiles (after configuration).  This allows inclusion of libraries from packages which do not use Automake (such as gettext).

In a deep package, the top-level Makefile.am is often very short. For instance, here is the Makefile.am from the textutils distribution:

     SUBDIRS = lib src doc man

SUBDIRS can contain configure substitutions (eg @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.

The use of SUBDIRS is not restricted to just the top-level Makefile.am.  Automake can be used to construct packages of arbitrary depth.

Building Programs and Libraries
*******************************

A large part of Automake's functionality is dedicated to making it easy to build C programs and libraries.

Building a program
==================

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.

For instance:

     bin_PROGRAMS = hello

In this simple case, the resulting Makefile.in will contain code to generate a program named hello.  The variable hello_SOURCES is used to specify which source files get built into an executable:

     hello_SOURCES = hello.c

This causes hello.c to be compiled into hello.o, and then linked to produce hello.

If prog_SOURCES is needed, but not specified, then it defaults to the single file prog.c.  In the example above, the definition of hello_SOURCES is actually redundant.

Multiple programs can be built in a single directory.  Multiple programs can share a single source file.  The source file 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 an _SOURCES variable; this file should not be distributed. Lex (.l) and yacc (.y) files can also be listed; support for these should work but is still preliminary.

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.

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 = ...

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 all the -l and -L options removed.  Be warned that configure substitutions are preserved; this can lead to bad dependencies if you are not careful.

Building a library
==================

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.

Each _LIBRARIES variable is a list of the libraries to be built. For instance to create a library named libcpio.a, but not install it, you would write:

     noinst_LIBRARIES = libcpio.a

The sources that go into a library are determined exactly as they are for programs, via the _SOURCES variables.  Note that the library name is canonicalized (see Canonicalization), so the _SOURCES variable corresponding to liblob.a is liblob_a_SOURCES, not liblob.a_SOURCES.

Extra objects can be added to a library using the library_LIBADD variable.  This should be used for objects determined by configure.  Again from cpio:

     libcpio_a_LIBADD = @LIBOBJS@ @ALLOCA@

Special handling for LIBOBJS and ALLOCA
=======================================

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 Dist). These source files are also automatically handled in the dependency-tracking scheme, see Dependencies.

@LIBOBJS@ and @ALLOCA@ are specially recognized in any _LDADD or _LIBADD variable.

Variables used when building a program
======================================

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:

INCLUDES
     A list of -I options.  This can be set in your Makefile.am if you have special directories you want to look in.

COMPILE
     This is the command used to actually compile a C source file.  The filename is appended to form the complete command line.

LINK
     This is the command used to actually link a C program.

Yacc and Lex support
====================

Automake has somewhat idiosyncratic support for Yacc and Lex. FIXME: describe it here.

C++ and other languages
=======================

Automake includes full support for C++, and rudimentary support for other languages.  Support for other languages will be improved based on demand.

Any package including C++ code must use AC_PROG_CXX in its configure.in.

A few additional variables are defined when a C++ source file is seen:

CXX
     The name of the C++ compiler.

CXXFLAGS
     Any flags to pass to the C++ compiler.

CXXCOMPILE
     The command used to actually compile a C++ source file.  The file name is appended to form the complete command line.

CXXLINK
     The command used to actually link a C++ program.

Automatic de-ANSI-fication
==========================

Although the GNU standards prohibit it, some GNU programs are written in ANSI C; see FIXME.  This is possible because each source file can be ``de-ANSI-fied'' before the actual compilation takes place.

If the Makefile.am variable AUTOMAKE_OPTIONS (Options) contains the option ansi2knr then code to handle de-ANSI-fication is inserted into the generated Makefile.in.

This causes each source file to be treated as ANSI C.  If an ANSI C compiler is available, it is used.

This support requires the source files ansi2knr.c and ansi2knr.1 to be in the same directory as the ANSI C source; these files are distributed with Automake. Also, the package configure.in must call the macro AM_C_PROTOTYPES.

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

Note that the directory holding the ansi2knr support files must be built before all other directories using these files.  Automake does not currently check that this is the case.

Note also that ansi2knr assumes the source code will be formatted in a particular way.  See the ansi2knr man page for details.

Automatic dependency tracking
=============================

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, and distribute the dependencies in the generated Makefile.in.

Currently this support requires the use of GNU make and gcc.  It might become possible in the future to supply a different dependency generating program, if there is enough demand.

This mode is enabled by default if any C program or library is defined in the current directory.

When you decide to make a distribution, the dist target will re-run automake with the --include-deps option.  This causes the previously generated dependencies to be inserted into the generated Makefile.in, and thus into the distribution. --include-deps also turns off inclusion of the dependency generation code.

This mode can be suppressed by putting no-dependencies in the variable AUTOMAKE_OPTIONS.

If you unpack a distribution made by make dist, and you want to turn on the dependency-tracking code again, simply run automake with no arguments.

Other Derived Objects
*********************

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.

Executable Scripts
==================

It is possible to define and install programs which are scripts.  Such programs are listed using the SCRIPTS primary name. automake doesn't define any dependencies for scripts; the Makefile.am should include the appropriate rules.

automake does not assume that scripts are derived objects; such objects must be deleted by hand; see Clean for more information.

automake itself is a 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
============

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.

All header files must be listed somewhere; missing ones will not appear in the distribution.  Often it is clearest to list uninstalled headers with the rest of the sources for a program.  See A Program.  Headers listed in a _SOURCES variable need not be listed in any _HEADERS variable.

Headers can be installed in includedir, oldincludedir, or pkgincludedir.

Architecture-independent data files
===================================

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.

Here is how automake installs its auxiliary data files:

     pkgdata_DATA = clean-kr.am clean.am compile-kr.am compile-vars.am \
     compile.am data.am depend.am dist-subd-top.am dist-subd-vars.am \
     dist-subd.am dist-vars.am dist.am footer.am header-vars.am header.am \
     libscripts.am libprograms.am libraries-vars.am libraries.am library.am \
     mans-vars.am mans.am packagedata.am program.am programs.am remake-hdr.am \
     remake-subd.am remake.am scripts.am subdirs.am tags.am tags-subd.am \
     texinfos-vars.am texinfos.am hack-make.sed nl-remove.sed

Built sources
=============

Occasionally a file which would otherwise be called ``source'' (eg a C .h file) is actually derived from some other file.  Such files should be listed in the BUILT_SOURCES variable.

Files listed in BUILT_SOURCES are built before any automatic dependency tracking is done.  By default, built sources are not included in a distribution.

Other GNU Tools
***************

Since Automake is primarily intended to generate Makefile.ins for use in GNU programs, it tries hard to interoperatoe with other GNU tools.

Emacs Lisp
==========

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 (fixme xref).

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.

Gettext
=======

If ud_GNU_GETTEXT is seen in configure.in, then Automake turns on support for GNU gettext, a message catalog system for internationalization (see GNU Gettext (GNU gettext utilities)).

The gettext support in Automake requires the addition of two subdirectories to the package, intl and po.  Automake ensure that these directories exist and are mentioned in SUBDIRS.

Furthermore, Automake checks that the definition of ALL_LINGUAS in configure.in corresponds to all the valid .po files, and nothing more.

Building documentation
**********************

Currently Automake provides support for Texinfo and man pages.

Texinfo
=======

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.  Note that any Texinfo source file must end in the .texi or .texinfo extension.

If the .texi file @includes version.texi, then that file will be automatically generated.  version.texi defines three Texinfo macros you can reference: EDITION, VERSION, and UPDATED.  The first two hold the version number of your package (but are kept separate for clarity); the last is the date the primary file was last modified.  The version.texi support requires the mdate-sh program; this program is supplied with Automake.

Sometimes an info file actually depends on more than one .texi file.  For instance, in the xdvik distribution, kpathsea.texi includes the files install.texi, copying.texi, and freedom.texi.  You can tell Automake about these dependencies using the texi_TEXINFOS variable.  Here is how xdvik could do it:

     info_TEXINFOS = kpathsea.texi
     kpathsea_TEXINFOS = install.texi copying.texi freedom.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, then texinfo.tex is looked for there.  Automake supplies texinfo.tex.

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.

Man pages
=========

A package can also include man pages.  (Though see the GNU standards on this matter, Man Pages (The GNU Coding Standards).)  Man pages are declared using the MANS primary. Generally the man_MANS macro is used.  Man pages are automatically installed in the correct subdirectory of mandir, based on the file extension.

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 documentation is handled in GNU cpio (which includes both Texinfo documentation and man pages):

     info_TEXINFOS = cpio.texi
     man_MANS = cpio.1 mt.1

Texinfo source, info pages and man pages are all considered to be source for the purposes of making a distribution.

What Gets Installed
*******************

Naturally, Automake handles the details of actually installing your program once it has been built.  All PROGRAMS, SCRIPTS, LIBRARIES, LISP, DATA and HEADERS are automatically installed in the appropriate places.

Automake also handles installing any specified info and man pages.

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.  The install target depends on both of these targets.

Automake also generates an uninstall target, and an installdirs target.

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.

What Gets Cleaned
*****************

The GNU Makefile Standards specify a number of different clean rules. Generally the files that can 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.

What Goes in a Distribution
***************************

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.

For the most part, the files to distribute are automatically found by Automake: all source files are automatically included in a distribution, as are all Makefile.ams and Makefile.ins.  Automake also has a built-in list of commonly used files which, if present in the current directory, are automatically included.  This list is printed by automake --help.  Also, files which are read by configure (ie, 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.  Note that EXTRA_DIST can only handle files in the current directory; files in other directories will cause make dist runtime failures.

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 file in subdirectories for which a new Makefile.am is overkill:

     dist-hook:
             mkdir $(distdir)/random
             cp -p random/a1 random/a2 $(distdir)/random

Automake also generates a distcheck target which can be help to ensure that a given distribution will actually work.  distcheck makes a distribution, and then tries to do a VPATH build.

Support for test suites
***********************

Automake supports a two forms of test suite.

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 ..  The number of failures will be printed at the end of the run.  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 dejagnu appears in AUTOMAKE_OPTIONS, then the a dejagnu-based test suite is assumed.  The value of the variable DEJATOOL is passed as the --tool argument to runtest; it defaults to the name of the package.  The variables EXPECT, RUNTEST and RUNTESTFLAGS 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.

In either case, the testing is done via make check.

Changing Automake's Behavior
****************************

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
     The same as the corresponding --strictness option.

no-installman
     The generated Makefile.in will not cause man pages to be installed by default.  However, an install-man target will still be available for optional installation.  This option is disallowed at GNU strictness and above.

no-installinfo
     The generated Makefile.in will not cause info pages to be built or installed by default.  However, info and install-info targets will still be available.  This option is disallowed at GNU strictness and above.

ansi2knr

path/ansi2knr
     Turn on automatic de-ANSI-fication.  See ANSI.  If preceeded by a path, the generated Makefile.in will look in the specified directory to find the ansi2knr program.  Generally the path should be a relative path to another directory in the same distribution (though Automake currently does not check this).  It is up to you to make sure that the specified directory is built before the current directory; if ansi2knr does not exist then the build will fail.

dejagnu
     Cause dejagnu-specific rules to be generated.  See Tests.

dist-shar
     Generate a dist-shar target as well as the ordinary dist target.  This new target will create a shar archive of the distribution.

dist-zip
     Generate a dist-zip target as well as the ordinary dist target.  This new target will create a zip archive of the distribution.

dist-tarZ
     Generate a dist-tarZ target as well as the ordinary dist target.  This new target will create a compressed tar archive of the distribution; a traditional tar and compress will be assumed.  Warning: if you are actually using GNU tar, then the generated archive might contain nonportable constructs.

no-dependencies
     This is similar to using --include-deps on the command line, but is useful for those situations where you don't have the necessary bits to make automatic dependency tracking work see Dependencies.  In this case the effect is to effectively disable automatic dependency tracking.

VERSION
     A version number (eg 0.30) can be specified.  If Automake is not newer than the version specified, creation of the Makefile.in will be suppressed.

Unrecognized options are diagnosed by automake.

Miscellaneous Rules
*******************

There are a few rules and variables that didn't fit anywhere else.

Interfacing to etags
====================

automake will generate rules to generate TAGS files for use with GNU Emacs under some circumstances.

If any C source code or headers are present, then a tags target 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.

Also, if the variable ETAGS_ARGS is defined, a tags target will be generated.  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.

Handling new file extensions
============================

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, currently automake does not provide any Java support.  If you wrote a macro to generate .class files from .java source files, you would also need to add these suffixes to the list:

     SUFFIXES = .java .class

Built sources
=============

FIXME write this

The effect of --gnu and --gnits
*******************************

The --gnu option (or gnu in the AUTOMAKE_OPTIONS variable) causes automake to check the following:

  * The files INSTALL, NEWS, README, COPYING, AUTHORS, and ChangeLog are required at the topmost directory of the package.

  * The options no-installman and no-installinfo are prohibited.

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:

  * make dist will check to make sure the NEWS file has been updated to the current version.

  * The file COPYING.LIB is prohibited.

  * VERSION is checked to make sure its format complies with Gnits standards.

  * If VERSION indicates that this is an alpha release, and the file README-alpha appears in the topmost directory of a package, then it is included in the distribution.

  * The file THANKS is required.

When Automake Isn't Enough
**************************

Sometimes automake isn't enough.  Then you just lose.

Actually, automakes 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 non-flat package.  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, and uninstall.  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 how 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

Distributing Makefile.ins
*************************

Automake places no restrictions on the distribution of the resulting Makefile.ins.  We still encourage software authors to distribute their work under terms like those of the GPL, but doing so is not required to use Automake.

Some of the files that can be automatically installed via the --add-missing switch do fall under the GPL; examine each file to see.

Some example packages
*********************

Here are some examples of how Automake can be used.

The simplest GNU program
========================

hello is renowned for its classic simplicity and versatility. What better place to begin a tour?  The below shows what could be used as the Hello distribution's Makefile.am.

     bin_PROGRAMS = hello
     hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h
     hello_LDADD = @ALLOCA@
     info_TEXINFOS = hello.texi
     hello_TEXINFOS = gpl.texi

     EXTRA_DIST = testdata

     check-local: hello
             @echo expect no output from diff
             ./hello > test.out
             diff -c $(srcdir)/testdata test.out
             rm -f test.out

Of course, Automake also requires some minor changes to configure.in.  The new configure.in would read:

     dnl Process this file with autoconf to produce a configure script.
     AC_INIT(hello.c)
     AM_INIT_AUTOMAKE(hello, 1.3)
     AC_PROG_CC
     AC_PROG_CPP
     AC_PROG_INSTALL
     AC_STDC_HEADERS
     AC_HAVE_HEADERS(string.h fcntl.h sys/file.h)
     AC_ALLOCA
     AC_OUTPUT(Makefile)

If Hello were really going to use Automake, the version.c file would probably be deleted, or changed so as to be automatically generated.

A tricker example
=================

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
     ctags_DEPENDENCIES = ctags.o

     etags.o:
             $(COMPILE) -DETAGS_REGEXPS etags.c

     ctags.o:
             $(COMPILE) -DCTAGS -o ctags.o 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, while ctags_DEPENDENCIES exists to make sure that ctags.o gets built in the first place.

This is a somewhat pathological example.

Automake uses itself
====================

Automake, of course, uses itself to generate its Makefile.in. Since Automake is a shallow package, it has more than one Makefile.am.  Here is the top-level Makefile.am:

     ## Process this file with automake to create Makefile.in

     AUTOMAKE_OPTIONS = gnits
     MAINT_CHARSET = latin1
     PERL = @PERL@

     SUBDIRS = tests

     bin_SCRIPTS = automake
     info_TEXINFOS = automake.texi

     pkgdata_DATA = clean-kr.am clean.am compile-kr.am compile-vars.am \
     compile.am data.am depend.am \
     dist-vars.am footer.am header.am header-vars.am \
     kr-vars.am libraries-vars.am \
     libraries.am library.am mans-vars.am \
     program.am programs.am remake-hdr.am \
     remake-subd.am remake.am scripts.am subdirs.am tags.am tags-subd.am \
     tags-clean.am \
     texi-version.am texinfos-vars.am texinfos.am \
     libraries-clean.am programs-clean.am data-clean.am \
     COPYING INSTALL texinfo.tex \
     ansi2knr.c ansi2knr.1 \
     aclocal.m4

     ## These must all be executable when installed.
     pkgdata_SCRIPTS = config.guess config.sub install-sh mdate-sh mkinstalldirs

     # The following requires a fixed version of the Emacs 19.30 etags.
     ETAGS_ARGS = automake.in --lang=none \
      --regex='/^@node[ \t]+\([^,]+\)/\1/' automake.texi

     ## `test -x' is not portable.  So we use Perl instead.  If Perl
     ## doesn't exist, then this test is meaningless anyway.
     # Check to make sure some installed files are executable.
     installcheck-local:
     	$(PERL) -e "exit ! -x '$(pkgdatadir)/config.guess';"
     	$(PERL) -e "exit ! -x '$(pkgdatadir)/config.sub';"
     	$(PERL) -e "exit ! -x '$(pkgdatadir)/install-sh';"
     	$(PERL) -e "exit ! -x '$(pkgdatadir)/mdate-sh';"
     	$(PERL) -e "exit ! -x '$(pkgdatadir)/mkinstalldirs';"

     # Some simple checks:
     # * syntax check with perl4 and perl5.
     # * make sure the scripts don't use 'true'
     # * expect no instances of '${...}'
     # These are only really guaranteed to work on my machine.
     maintainer-check: automake check
     	$(PERL) -c -w automake
     	@if grep '^[^#].*true' $(srcdir)/[a-z]*.am; then \
     	  echo "can't use 'true' in GNU Makefile" 1>&2; \
     	  exit 1;				\
     	else :; fi
     	@if test `fgrep '$${' $(srcdir)/[a-z]*.am | wc -l` -ne 0; then \
     	  echo "found too many uses of '\$${'" 1>&2; \
     	  exit 1;				\
     	fi
     	if $(SHELL) -c 'perl4.036 -v' >/dev/null 2>&1; then \
     	  perl4.036 -c -w automake; \
     	else :; fi

     # Tag before making distribution.  Also, don't make a distribution if
     # checks fail.  Also, make sure the NEWS file is up-to-date.
     cvs-dist: maintainer-check
     	@if sed 1q NEWS | grep -e "$(VERSION)" > /dev/null; then :; else \
     	  echo "NEWS not updated; not releasing" 1>&2; \
     	  exit 1;				\
     	fi
     	cvs tag `echo "Release-$(VERSION)" | sed 's/\./-/g'`
     	$(MAKE) dist

As you can see, Automake defines many of its own rules, to make the maintainer's job easier.  For instance the cvs-dist rule automatically tags the current version in the CVS repository, and then makes a standard distribution.

Automake consists primarily of one program, automake, and a number of auxiliary scripts.  Automake also installs a number of programs which are possibly installed via the --add-missing option; these scripts are listed in the pkgdata_SCRIPTS variable.

Automake also has a tests subdirectory, as indicated in the SUBDIRS variable above.  Here is tests/Makefile.am:

     ## Process this file with automake to create Makefile.in

     AUTOMAKE_OPTIONS = gnits

     TESTS = mdate.test vtexi.test acoutput.test instexec.test checkall.test \
     acoutnoq.test acouttbs.test libobj.test proginst.test acoutqnl.test \
     confincl.test spelling.test prefix.test badprog.test depend.test

     EXTRA_DIST = defs

This is where all the tests are really run.  defs is an initialization file used by each test script; it is explicitly mentioned because automake has no way of automatically finding it.

A deep hierarchy
================

The GNU textutils are a collection of programs for manipulating text files.  They are distributed as a deep package.  The textutils have only recently been modified to use Automake; the examples come from a prerelease.

Here is the top-level Makefile.am:

     SUBDIRS = lib src doc man

In the lib directory, a library is built which is used by each textutil.  Here is lib/Makefile.am:

     noinst_LIBRARIES = tu

     EXTRA_DIST = rx.c regex.c

     tu_SOURCES = error.h getline.h getopt.h linebuffer.h \
     long-options.h md5.h regex.h rx.h xstrtod.h xstrtol.h xstrtoul.h \
     error.c full-write.c getline.c getopt.c getopt1.c \
     linebuffer.c long-options.c md5.c memchr.c safe-read.c \
     xmalloc.c xstrtod.c xstrtol.c xstrtoul.c

     tu_LIBADD = @REGEXOBJ@ @LIBOBJS@ @ALLOCA@

The src directory contains the source for all the textutils -- 23 programs in all.  The Makefile.am for this directory also includes some simple checking code, and constructs a version.c file on the fly:

     bin_PROGRAMS = cat cksum comm csplit cut expand fmt fold head join md5sum \
     nl od paste pr sort split sum tac tail tr unexpand uniq wc

     noinst_HEADERS = system.h version.h
     DISTCLEANFILES = stamp-v version.c

     INCLUDES = -I$(top_srcdir)/lib

     LDADD = version.o ../lib/libtu.a

     $(PROGRAMS): version.o ../lib/libtu.a

     AUTOMAKE_OPTIONS = ansi2knr

     version.c: stamp-v
     stamp-v: Makefile
     	rm -f t-version.c
     	echo '#include <config.h>' > t-version.c
     	echo '#include "version.h"' >> t-version.c
     	echo 'const char *version_string = "'GNU @PACKAGE@ @VERSION@'";' \
     		>> t-version.c
     	if cmp -s version.c t-version.c; then	\
     	  rm t-version.c;			\
     	else					\
     	  mv t-version.c version.c;		\
     	fi
     	echo timestamp > $@

     check: md5sum
     	./md5sum \
     	 --string="" \
     	 --string="a" \
     	 --string="abc" \
     	 --string="message digest" \
     	 --string="abcdefghijklmnopqrstuvwxyz" \
     	 --string="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" \
     	 --string="12345678901234567890123456789012345678901234567890123456789012345678901234567890" \
            | diff -c $(srcdir)/md5-test.rfc -

The doc directory builds the info documentation for the textutils:

     info_TEXINFOS = textutils.texi

And, last, the man directory installs the man pages for all the textutils:

     man_MANS = cat.1 cksum.1 comm.1 csplit.1 cut.1 expand.1 fmt.1 fold.1 head.1 \
     join.1 md5sum.1 nl.1 od.1 paste.1 pr.1 sort.1 split.1 sum.1 tac.1 tail.1 \
     tr.1 unexpand.1 uniq.1 wc.1

You can now see how easy it is to handle even a largish project using Automake.

Some ideas for the future
*************************

Here are some things that might happen in the future:

  * HTML support.

  * The output will be cleaned up.  For instance, only variables which are actually used will appear in the generated Makefile.in.

  * There will be support for automatically recoding a distribution.  The intent is to allow a maintainer to use whatever character set is most convenient locally, but for all distributions to be Unicode or ISO 10646 with the UTF-8 encoding.