     [file version.texi not included]

     START-INFO-DIR-ENTRY
     * automake: (automake).		Making Makefile.in's
     END-INFO-DIR-ENTRY

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 tromey@cygnus.com.

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:

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

--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.

--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.

--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.

--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.

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

--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
*************

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 accomodate 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.

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, SCRIPTS, DATA, HEADERS, MANS, and TEXINFOS.

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

Automake essentially works by reading a Makefile.am and generating a Makefile.in.  The macro definitions and targets in the Makefile.am are copied into the generated file.

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.

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

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

Automake requires certain variables to be defined and certain macros to be used in the package configure.in.

One such requirement is that configure.in must 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 definees 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 also requires the use of the macros AC_ARG_PROGRAM

If your package is not a flat distribution, Automake requires the use of AC_PROG_MAKE_SET.

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.

AC_OUTPUT
     Automake uses this to determine which files to create.

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_CANONICAL_SYSTEM
     Automake will ensure that config.guess and config.sub exist.

AC_FUNC_ALLOCA

AC_FUNC_GETLOADAVG

AC_FUNC_MEMCMP

AC_STRUCT_ST_BLOCKS

fp_FUNC_FNMATCH

AC_REPLACE_FUNCS
     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.

     Automake will also detect statements which put .o files into LIBOBJS, and will treat these additional files in a similar way.

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

AC_PROG_INSTALL

fp_PROG_INSTALL
     fp_PROG_INSTALL is required if any scripts (see Scripts) are installed by the package.  Otherwise, AC_PROG_INSTALL is required.

fp_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 (FIXME xref). It is distributed with gettext.  Automake uses this macro to ensure that the package meets some of gettext's requirements.

The fp_ macros are from Franc,ois Pinard, and are included with Automake.  automake will tell where the macros can be found if they are missing.

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
     EXTRA_DIST = @README_ALPHA@

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.

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.  Id est 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 ignored. 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 builts 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.

Since program names are rewritten into Makefile macro names, program names must follow Makefile macro syntax.  Sometimes it is useful to have a program whose name does not follow such rules.  In these cases, Automake canonicalizes the program name.  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, you would use sniff_glue_SOURCES, not sniff-glue_SOURCES.

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 base names of libraries to be built.  For instance to create a library named libcpio.a, but not install it, you would write:

     noinst_LIBRARIES = cpio

The sources that go into a library are determined exactly as they are for programs, via the _SOURCES variables.  Note that programs and libraries share a namespace, so one cannot have a program (lob) and a library (liblob.a) with the same name in one directory.

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:

     cpio_LIBADD = @LIBOBJS@ @ALLOCA@

Note that Automake explicitly recognizes the use of @LIBOBJS@ and @ALLOCA@ in the above example, 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.

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 fp_C_PROTOTYPES.

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.

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 are 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, dependencies for it are 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 most convenient to list uninstalled headers with the rest of the sources for a program.  See A Program.

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.

All such data files are included in the distribution.

Here is how autoconf 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.  Built sources are included in a distribution.

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 extension (.texinfo won't work).

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

Automake will warn if a directory containing Texinfo source does not also contain the file texinfo.tex.  This file is supplied with Automake.

Automake generates an install-info target; some people apparently use this.

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, 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.

In Automake, the automake program is not automatically removed, because it is an executable script.  So this code in Makefile.am causes it to be removed by make clean:

     CLEANFILES = automake

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.

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.

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

Automake supports a simple form 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 testing is done via make check.  The number of failures will be printed at the end of the run.

In the future there will be some support for test suites which use DejaGnu.

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.

ansi2knr
     Turn on automatic de-ANSI-fication.

dist-shar
     Generate a dist-shar target as well as the ordinary dist target.

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

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.

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

FIXME write this

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.

For instance, here is how to install a file in /etc:

     install-data-local:
             $(INSTALL_DATA) $(srcdir)/afile /etc/afile

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)
     VERSION=1.3
     AC_SUBST(VERSION)
     PACKAGE=hello
     AC_SUBST(PACKAGE)
     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

     CLEANFILES = automake

     # 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.