doc update from akim

[automake.git] / automake.texi

\input texinfo   @c -*-texinfo-*-
@c %**start of header
@setfilename automake.info
@settitle automake
@setchapternewpage off
@c %**end of header

@include version.texi

@dircategory GNU admin
@direntry
* automake: (automake).         Making Makefile.in's
@end direntry

@dircategory Individual utilities
@direntry
* aclocal: (automake)Invoking aclocal.          Generating aclocal.m4
@end direntry

@ifinfo
This file documents GNU automake @value{VERSION}

Copyright (C) 1995, 96, 97 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.

@ignore
Permission is granted to process this file through TeX and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph


@end ignore
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.
@end ifinfo


@titlepage
@title GNU Automake
@subtitle For version @value{VERSION}, @value{UPDATED}
@author David MacKenzie and Tom Tromey

@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1995, 96 Free Software Foundation, Inc.
@sp 2
This is the first edition of the GNU Automake documentation,@*
and is consistent with GNU Automake @value{VERSION}.@*
@sp 2
Published by the Free Software Foundation @*
59 Temple Place - Suite 330, @*
Boston, MA 02111-1307 USA @*

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 Free Software Foundation.
@end titlepage

@c Define an index of configure variables.
@defcodeindex cv
@c Define an index of options.
@defcodeindex op
@c Define an index of targets.
@defcodeindex tr

@c Put everything in one index (arbitrarily chosen to be the concept index).
@syncodeindex cv cp
@syncodeindex op cp
@syncodeindex tr cp
@syncodeindex vr cp

@ifinfo
@node Top, Introduction, (dir), (dir)
@comment  node-name,  next,  previous,  up
@top GNU Automake

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

@menu
* Introduction::                Automake's purpose
* Generalities::                General ideas
* Examples::                    Some example packages
* Invoking Automake::           Creating a Makefile.in
* configure::                   Scanning configure.in
* Top level::                   The top-level Makefile.am
* Programs::                    Building programs and libraries
* Other objects::               Other derived objects
* Other GNU Tools::             Other GNU Tools
* Documentation::               Building documentation
* Install::                     What gets installed
* Clean::                       What gets cleaned
* Dist::                        What goes in a distribution
* Tests::                       Support for test suites
* Options::                     Changing Automake's behavior
* Miscellaneous::               Miscellaneous rules
* Conditionals::                Conditionals
* Gnits::                       The effect of @code{--gnu} and @code{--gnits}
* Cygnus::                      The effect of @code{--cygnus}
* Extending::                   Extending Automake
* Distributing::                Distributing the Makefile.in
* Future::                      Some ideas for the future
* Index::                       General index

 --- The Detailed Node Listing ---

General ideas

* General Operation::           General operation of Automake
* Depth::                       The kinds of packages
* Strictness::                  Standards conformance checking
* Uniform::                     The Uniform Naming Scheme
* Canonicalization::            How derived variables are named

Some example packages

* Complete::                    A simple example, start to finish
* Hello::                       A classic program
* etags::                       Building etags and ctags

Scanning @file{configure.in}

* Requirements::                Configuration requirements
* Optional::                    Other things Automake recognizes
* Invoking aclocal::            Auto-generating aclocal.m4
* Macros::                      Autoconf macros supplied with Automake
* Extending aclocal::           Writing your own aclocal macros

Building Programs and Libraries

* A Program::                   Building a program
* A Library::                   Building a library
* LIBOBJS::                     Special handling for LIBOBJS and ALLOCA
* A Shared Library::            Building a Libtool library
* Program variables::           Variables used when building a program
* Yacc and Lex::                Yacc and Lex support
* C++::                         
* ANSI::                        Automatic de-ANSI-fication
* Dependencies::                Automatic dependency tracking

Other Derived Objects

* Scripts::                     Executable scripts
* Headers::                     Header files
* Data::                        Architecture-independent data files
* Sources::                     Derived sources

Other GNU Tools

* Emacs Lisp::                  Emacs Lisp
* gettext::                     Gettext
* Guile::                       Guile
* Libtool::                     Libtool

Building documentation

* Texinfo::                     Texinfo
* Man pages::                   Man pages

Miscellaneous Rules

* Tags::                        Interfacing to etags and mkid
* Suffixes::                    Handling new file extensions
@end menu

@end ifinfo

@node Introduction, Generalities, Top, Top
@chapter Introduction

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

The GNU Makefile Standards Document
(@pxref{Makefile Conventions, , , standards, 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
@file{Makefile.in}.  There should generally be one @file{Makefile.am}
per directory of a project.

Automake does constrain a project in certain ways; for instance it
assumes that the project uses Autoconf
(@pxref{Top, , The Autoconf Manual, autoconf, The Autoconf Manual}),
and enforces certain restrictions on the @file{configure.in} contents.

Automake requires @code{perl} in order to generate the
@file{Makefile.in}s.  However, the distributions created by Automake are
fully GNU standards-compliant, and do not require @code{perl} in order
to be built.

Mail suggestions and bug reports for Automake to
@email{automake-bugs@@gnu.ai.mit.edu}.


@node Generalities, Examples, Introduction, Top
@chapter General ideas

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

@menu
* General Operation::           General operation of Automake
* Depth::                       The kinds of packages
* Strictness::                  Standards conformance checking
* Uniform::                     The Uniform Naming Scheme
* Canonicalization::            How derived variables are named
@end menu

@node General Operation, Depth, Generalities, Generalities
@section General Operation

Automake works by reading a @file{Makefile.am} and generating a
@file{Makefile.in}.  Certain macros and targets defined in the
@file{Makefile.am} instruct automake to generate more specialized code;
for instances a @samp{bin_PROGRAMS} macro definition will cause targets
for compiling and linking to be generated.

The macro definitions and targets in the @file{Makefile.am} are copied
into the generated file.  This allows you to add arbitrary code into the
generated @file{Makefile.in}.  For instance the Automake distribution
includes a non-standard @code{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 @file{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 @file{Makefile.am} generally overrides any such
target of a similar name that would be automatically generated by
@code{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 @file{Makefile.am} will override any
definition of the variable that @code{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
@code{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.  E.g., if Automake is looking at
the content of @samp{foo_SOURCES} in this snippet

@example
xs = a.c b.c
foo_SOURCES = c.c $(xs)
@end example

it would use the files @file{a.c}, @file{b.c}, and @file{c.c} as the
contents of @samp{foo_SOURCES}.

Automake also allows a form of comment which is @emph{not} copied into
the output; all lines beginning with @samp{##} are completely ignored by
Automake.

It is customary to make the first line of @file{Makefile.am} read:

@example
## Process this file with automake to produce Makefile.in
@end example

@c FIXME discuss putting a copyright into Makefile.am here?  I would but
@c I don't know quite what to say.

@c FIXME document customary ordering of Makefile.am here!



@node Depth, Strictness, General Operation, Generalities
@section Depth
@code{automake} supports three kinds of directory hierarchy: ``flat'',
``shallow'', and ``deep''.

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

A @dfn{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
@code{tar}.  The top level @file{Makefile.am} for a deep package will
contain a @code{SUBDIRS} macro, but no other macros to define objects
which are built.

A @dfn{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
@code{make}, which does not currently use @code{automake}).


@node Strictness, Uniform, Depth, Generalities
@section 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 @dfn{strictness}---the
strictness indicating how stringently Automake should check standards
conformance.

The valid strictness levels are:

@table @samp
@item 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 @file{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.

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

@item 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.
@end table

For more information on the precise implications of the strictness
level, see @xref{Gnits}.


@node Uniform, Canonicalization, Strictness, Generalities
@section 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 @code{configure}
time determination of what should be built.

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

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
(@pxref{Directory Variables, , , standards, The GNU Coding
Standards}).
Automake extends this list with @code{pkglibdir}, @code{pkgincludedir},
and @code{pkgdatadir}; these are the same as the non-@samp{pkg}
versions, but with @samp{@@PACKAGE@@} appended.  For instance,
@code{pkglibdir} is defined as @code{$(datadir)/@@PACKAGE@@}.
@cvindex PACKAGE

For each primary, there is one additional variable named by prepending
@samp{EXTRA_} to the primary name.  This variable is used to list
objects which may or may not be built, depending on what
@code{configure} decides.  This variable is required because Automake
must statically know the entire list of objects to be built in order to
generate a @file{Makefile.in} that will work in all cases.

For instance, @code{cpio} decides at configure time which programs are
built.  Some of the programs are installed in @code{bindir}, and some
are installed in @code{sbindir}:

@example
EXTRA_PROGRAMS = mt rmt
bin_PROGRAMS = cpio pax
sbin_PROGRAMS = @@PROGRAMS@@
@end example

Defining a primary variable without a prefix (eg @code{PROGRAMS}) is an
error.

Note that the common @samp{dir} suffix is left off when constructing the
variable names; thus one writes @samp{bin_PROGRAMS} and not
@samp{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 @samp{zar}) is valid if a variable of
the same name with @samp{dir} appended is defined (eg @samp{zardir}).

For instance, until HTML support is part of Automake, you could use this
to install raw HTML documentation:

@example
htmldir = $(prefix)/html
html_DATA = automake.html
@end example

The special prefix @samp{noinst} indicates that the objects in question
should not be installed at all.

The special prefix @samp{check} indicates that the objects in question
should not be built until the @code{make check} command is run.

Possible primary names are @samp{PROGRAMS}, @samp{LIBRARIES},
@samp{LISP}, @samp{SCRIPTS}, @samp{DATA}, @samp{HEADERS}, @samp{MANS},
and @samp{TEXINFOS}.
@vindex PROGRAMS
@vindex LIBRARIES
@vindex LISP
@vindex SCRIPTS
@vindex DATA
@vindex HEADERS
@vindex MANS
@vindex TEXINFOS


@node Canonicalization,  , Uniform, Generalities
@section 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.  E.g., if your program is named
@code{sniff-glue}, the derived variable name would be
@code{sniff_glue_SOURCES}, not @code{sniff-glue_SOURCES}.


@node Examples, Invoking Automake, Generalities, Top
@chapter Some example packages

@menu
* Complete::                    A simple example, start to finish
* Hello::                       A classic program
* etags::                       Building etags and ctags
@end menu

@node Complete, Hello, Examples, Examples
@section A simple example, start to finish

Let's suppose you just finished writing @code{zardoz}, a program to make
your head float from vortex to vortex.  You've been using
@code{autoconf} to provide a portability framework, but your
@file{Makefile.in}s have been ad-hoc.  You want to make them
bulletproof, so you turn to @code{automake}.

The first step is to update your @file{configure.in} to include the
commands that @code{automake} needs.  The simplest way to do this is to
add an @code{AM_INIT_AUTOMAKE} call near the beginning:

@example
AM_INIT_AUTOMAKE(zardoz, 1.0)
@end example

Since your program doesn't have any complicating factors (e.g., it
doesn't use @code{gettext}, it doesn't want to build a shared library),
you're done with this part.  That was easy!

Now you must regenerate @file{configure}.  But to do that, you'll need
to tell @code{autoconf} how to find the new macro you've used.  The
easiest way to do this is to use the @code{aclocal} program to generate
your @file{aclocal.m4} for you.  But wait... you already have an
@file{aclocal.m4}, because you had to write some hairy macros for your
program.  @code{aclocal} lets you put your own macros into
@file{acinclude.m4}, so simply rename and then run:

@example
mv aclocal.m4 acinclude.m4
aclocal
autoconf
@end example

Now it is time to write your @file{Makefile.am} for @code{zardoz}.
@code{zardoz} is a user program, so you want to install it where the
rest of the user programs go.  @code{zardoz} also has some Texinfo
documentation.  Your @file{configure.in} script uses
@code{AC_REPLACE_FUNCS}, so you need to link against @samp{@@LIBOBJS@@}.
So here's what you'd write:

@example
bin_PROGRAMS = zardoz
zardoz_SOURCES = main.c head.c float.c vortex9.c gun.c
zardoz_LDADD = @@LIBOBJS@@

info_TEXINFOS = zardoz.texi
@end example

Now you can run @code{automake --add-missing} to generate your
@file{Makefile.in} and grab any auxiliary files you might need, and
you're done!


@node Hello, etags, Complete, Examples
@section A classic program

@code{hello} is renowned for its classic simplicity and versatility.
This section shows how Automake could be used with the Hello package.
The examples below are from the latest GNU Hello, but all the
maintainer-only code has been stripped out, as well as all copyright
comments.

Of course, GNU Hello is somewhat more featureful than your traditional
two-liner.  GNU Hello is internationalized, does option processing, and
has a manual and a test suite.  GNU Hello is a deep package.

Here is the @file{configure.in} from GNU Hello:

@example
dnl Process this file with autoconf to produce a configure script.
AC_INIT(src/hello.c)
AM_INIT_AUTOMAKE(hello, 1.3.11)
AM_CONFIG_HEADER(config.h)

dnl Set of available languages.
ALL_LINGUAS="de fr es ko nl no pl pt sl sv"

dnl Checks for programs.
AC_PROG_CC
AC_ISC_POSIX

dnl Checks for libraries.

dnl Checks for header files.
AC_STDC_HEADERS
AC_HAVE_HEADERS(string.h fcntl.h sys/file.h sys/param.h)

dnl Checks for library functions.
AC_FUNC_ALLOCA

dnl Check for st_blksize in struct stat
AC_ST_BLKSIZE

dnl internationalization macros
AM_GNU_GETTEXT
AC_OUTPUT([Makefile doc/Makefile intl/Makefile po/Makefile.in \
           src/Makefile tests/Makefile tests/hello],
   [chmod +x tests/hello])
@end example

The @samp{AM_} macros are provided by Automake (or the Gettext library);
the rest are standard Autoconf macros.


The top-level @file{Makefile.am}:

@example
EXTRA_DIST = BUGS ChangeLog.O
SUBDIRS = doc intl po src tests
@end example

As you can see, all the work here is really done in subdirectories.

The @file{po} and @file{intl} directories are automatically generated
using @code{gettextize}; they will not be discussed here.

In @file{doc/Makefile.am} we see:

@example
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
@end example

This is sufficient to build, install, and distribute the Hello manual.


Here is @file{tests/Makefile.am}:

@example
TESTS = hello
EXTRA_DIST = hello.in testdata
@end example

The script @file{hello} is generated by @code{configure}, and is the
only test case.  @code{make check} will run this test.

Last we have @file{src/Makefile.am}, where all the real work is done:

@example
bin_PROGRAMS = hello
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h 
hello_LDADD = @@INTLLIBS@@ @@ALLOCA@@
localedir = $(datadir)/locale
INCLUDES = -I../intl -DLOCALEDIR=\"$(localedir)\"
@end example


@node etags,  , Hello, Examples
@section Building etags and ctags

Here is another, trickier example.  It shows how to generate two
programs (@code{ctags} and @code{etags}) from the same source file
(@file{etags.c}).  The difficult part is that each compilation of
@file{etags.c} requires different @code{cpp} flags.

@example
bin_PROGRAMS = etags ctags
ctags_SOURCES =
ctags_LDADD = ctags.o

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

ctags.o: etags.c
        $(COMPILE) -DCTAGS -o ctags.o -c etags.c
@end example

Note that @code{ctags_SOURCES} is defined to be empty---that way no
implicit value is substituted.  The implicit value, however, is used to
generate @code{etags} from @file{etags.o}.

@code{ctags_LDADD} is used to get @file{ctags.o} into the link line.
@code{ctags_DEPENDENCIES} is generated by Automake.

The above rules won't work if your compiler doesn't accept both
@samp{-c} and @samp{-o}.  The simplest fix for this is to introduce a
bogus dependency (to avoid problems with a parallel @code{make}):

@example
etags.o: etags.c ctags.o
        $(COMPILE) -DETAGS_REGEXPS -c etags.c

ctags.o: etags.c
        $(COMPILE) -DCTAGS -c etags.c && mv etags.o ctags.o
@end example

Also, these explicit rules do not work if the de-ANSI-fication feature
is used; supporting that requires a little more work:

@example
etags._o: etags._c ctags.o
        $(COMPILE) -DETAGS_REGEXPS -c etags.c

ctags._o: etags._c
        $(COMPILE) -DCTAGS -c etags.c && mv etags._o ctags.o
@end example


@node Invoking Automake, configure, Examples, Top
@chapter Creating a @file{Makefile.in}

To create all the @file{Makefile.in}s for a package, run the
@code{automake} program in the top level directory, with no arguments.
@code{automake} will automatically find each appropriate
@file{Makefile.am} (by scanning @file{configure.in}; @pxref{configure})
and generate the corresponding @file{Makefile.in}.  Note that
@code{automake} has a rather simplistic view of what constitutes a
package; it assumes that a package has only one @file{configure.in}, at
the top.  If your package has multiple @file{configure.in}s, then you
must run @code{automake} in each directory holding a
@file{configure.in}.

You can optionally give @code{automake} an argument; @samp{.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 @file{Makefile.in}.  Note that @code{automake} must always
be run from the topmost directory of a project, even if being used to
regenerate the @file{Makefile.in} in some subdirectory.  This is
necessary because @code{automake} must scan @file{configure.in}, and
because @code{automake} uses the knowledge that a @file{Makefile.in} is
in a subdirectory to change its behavior in some cases.

@code{automake} accepts the following options:

@table @code
@item -a
@itemx --add-missing
Automake requires certain common files to exist in certain situations;
for instance @file{config.guess} is required if @file{configure.in} runs
@code{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.

@item --amdir=@var{dir}
Look for Automake data files in directory @var{dir} instead of in the
installation directory.  This is typically used for debugging.

@item --build-dir=@var{dir}
Tell Automake where the build directory is.  This option is used when
including dependencies into a @file{Makefile.in} generated by @code{make
dist}; it should not be used otherwise.

@item --cygnus
Causes the generated @file{Makefile.in}s to follow Cygnus rules, instead
of GNU or Gnits rules.  @xref{Cygnus} for more information.

@item --foreign
Set the global strictness to @samp{foreign}.  @xref{Strictness} for more
information.

@item --gnits
Set the global strictness to @samp{gnits}.  @xref{Gnits} for more
information.

@item --gnu
Set the global strictness to @samp{gnu}.  @xref{Gnits} for more
information.  This is the default strictness.

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

@item -i
@itemx --include-deps
Include all automatically generated dependency information
(@pxref{Dependencies}) in the generated
@file{Makefile.in}.  This is generally done when making a distribution;
see @ref{Dist}.

@item --no-force
Ordinarily @code{automake} creates all @file{Makefile.in}s mentioned in
@file{configure.in}.  This option causes it to only update those
@file{Makefile.in}s which are out of date with respect to one of their
dependents.

@item -o @var{dir}
@itemx --output-dir=@var{dir}
Put the generated @file{Makefile.in} in the directory @var{dir}.
Ordinarily each @file{Makefile.in} is created in the directory of the
corresponding @file{Makefile.am}.  This option is used when making
distributions.

@item --srcdir-name=@var{dir}
Tell Automake the name of the source directory associated with the
current build.  This option is used when including dependencies into a
@file{Makefile.in} generated by @code{make dist}; it should not be used
otherwise.

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

@item --version
Print the version number of Automake and exit.
@end table


@node configure, Top level, Invoking Automake, Top
@chapter Scanning @file{configure.in}

Automake scans the package's @file{configure.in} to determine certain
information about the package.  Some @code{autoconf} macros are required
and some variables must be defined in @file{configure.in}.  Automake
will also use information from @file{configure.in} to further tailor its
output.

Automake also supplies some @code{autoconf} macros to make the
maintenance easier.  These macros can automatically be put into your
@file{aclocal.m4} using the @code{aclocal} program.

@menu
* Requirements::                Configuration requirements
* Optional::                    Other things Automake recognizes
* Invoking aclocal::            Auto-generating aclocal.m4
* Macros::                      Autoconf macros supplied with Automake
* Extending aclocal::           Writing your own aclocal macros
@end menu


@node Requirements, Optional, configure, configure
@section Configuration requirements

The simplest way to meet the basic Automake requirements is to use the
macro @code{AM_INIT_AUTOMAKE} (@pxref{Macros}).  But if you prefer, you
can do the required steps by hand:
@cvindex AM_INIT_AUTOMAKE

@itemize @bullet
@item
Define the variables @code{PACKAGE} and @code{VERSION} with
@code{AC_SUBST}.
@cvindex PACKAGE
@cvindex VERSION
@code{PACKAGE} should be the name of the package as it appears when
bundled for distribution.  For instance, Automake defines @code{PACKAGE}
to be @samp{automake}.  @code{VERSION} should be the version number of
the release that is being developed.  We recommend that you make
@file{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 @code{PACKAGE} or
@code{VERSION}, except in @samp{Gnits} mode (@pxref{Gnits}).

@item
Use the macro @code{AC_ARG_PROGRAM} if a program or script is installed.
@cvindex AC_ARG_PROGRAM

@item
Use @code{AC_PROG_MAKE_SET} if the package is not flat.
@cvindex AC_PROG_MAKE_SET

@item
Use @code{AM_SANITY_CHECK} to make sure the build environment is sane.

@item
Use @code{AM_PROG_INSTALL} if any scripts (@pxref{Scripts}) are
installed by the package.  Otherwise, use @code{AC_PROG_INSTALL}.
@cvindex AC_PROG_INSTALL
@cvindex AM_PROG_INSTALL

@item
Use @code{AM_MISSING_PROG} to see whether the programs @code{aclocal},
@code{autoconf}, @code{automake}, @code{autoheader}, and @code{makeinfo}
are in the build environment.  Here is how this is done:
@example
missing_dir=`cd $ac_aux_dir && pwd`
AM_MISSING_PROG(ACLOCAL, aclocal, $missing_dir)
AM_MISSING_PROG(AUTOCONF, autoconf, $missing_dir)
AM_MISSING_PROG(AUTOMAKE, automake, $missing_dir)
AM_MISSING_PROG(AUTOHEADER, autoheader, $missing_dir)
AM_MISSING_PROG(MAKEINFO, makeinfo, $missing_dir)
@end example
@end itemize


Here are the other macros which Automake requires but which are not run
by @code{AM_INIT_AUTOMAKE}:

@table @code
@item AC_OUTPUT
Automake uses this to determine which files to create.  Listed files
named @code{Makefile} are treated as @file{Makefile}s.  Other listed
files are treated differently.  Currently the only difference is that a
@file{Makefile} is removed by @code{make distclean}, while other files
are removed by @code{make clean}.
@c FIXME: this is in violation of standards!
@cvindex AC_OUTPUT
@end table

@node Optional, Invoking aclocal, Requirements, configure
@section Other things Automake recognizes

Automake will also recognize the use of certain macros and tailor the
generated @file{Makefile.in} appropriately.  Currently recognized macros
and their effects are:

@table @code
@item AC_CONFIG_HEADER
Automake requires the use of @code{AM_CONFIG_HEADER}, which is similar
to @code{AC_CONFIG_HEADER} but does some useful Automake-specific work.
@cvindex AC_CONFIG_HEADER

@item AC_CONFIG_AUX_DIR
Automake will look for various helper scripts, such as
@file{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 @file{Makefile.am}, whichever is
appropriate).
@cvindex AC_CONFIG_AUX_DIR
FIXME: give complete list of things looked for in this directory

@item AC_PATH_XTRA
Automake will insert definitions for the variables defined by
@code{AC_PATH_XTRA} into each @file{Makefile.in} that builds a C program
or library.
@cvindex AC_PATH_XTRA

@item AC_CANONICAL_HOST
@itemx AC_CHECK_TOOL
Automake will ensure that @file{config.guess} and @file{config.sub}
exist.  Also, the @file{Makefile} variables @samp{host_alias} and
@samp{host_triplet} are introduced.
@c fixme xref autoconf docs.
@cvindex AC_CANONICAL_HOST
@cvindex AC_CHECK_TOOL
@vindex host_alias
@vindex host_triplet

@item AC_CANONICAL_SYSTEM
This is similar to @code{AC_CANONICAL_HOST}, but also defines the
@file{Makefile} variables @samp{build_alias} and @samp{target_alias}.
@cvindex AC_CANONICAL_SYSTEM
@vindex build_alias
@vindex target_alias

@item AC_FUNC_ALLOCA
@itemx AC_FUNC_GETLOADAVG
@itemx AC_FUNC_MEMCMP
@itemx AC_STRUCT_ST_BLOCKS
@itemx AC_FUNC_FNMATCH
@itemx AM_FUNC_STRTOD
@itemx AC_REPLACE_FUNCS
@itemx AC_REPLACE_GNU_GETOPT
@itemx AM_WITH_REGEX
Automake will ensure that the appropriate dependencies are generated for
the objects corresponding to these macros.  Also, Automake will verify
that the appropriate source files are part of the distribution.  Note
that Automake does not come with any of the C sources required to use
these macros, so @code{automake -a} will not install the sources.
@xref{A Library} for more information.
@cvindex AC_FUNC_ALLOCA
@cvindex AC_FUNC_GETLOADAVG
@cvindex AC_FUNC_MEMCMP
@cvindex AC_STRUCT_ST_BLOCKS
@cvindex AC_FUNC_FNMATCH
@cvindex AC_FUNC_FNMATCH
@cvindex AC_REPLACE_FUNCS
@cvindex AC_REPLACE_GNU_GETOPT
@cvindex AM_FUNC_STRTOD
@cvindex AM_WITH_REGEX

@item LIBOBJS
Automake will detect statements which put @samp{.o} files into
@code{LIBOBJS}, and will treat these additional files as if they were
discovered via @code{AC_REPLACE_FUNCS}.
@cvindex LIBOBJS

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

@item AC_PROG_CXX
This is required if any C++ source is included.
@cvindex AC_PROG_CXX

@item AM_PROG_LIBTOOL
Automake will turn on processing for @code{libtool} (@pxref{Top, , The
Libtool Manual, libtool, The Libtool Manual}).
@cvindex AM_PROG_LIBTOOL

@item AC_PROG_YACC
If a Yacc source file is seen, then you must either use this macro or
define the variable @samp{YACC} in @file{configure.in}.  The former is
preferred.
@cvindex AC_PROG_YACC
@cvindex YACC

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

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

@item ALL_LINGUAS
If Automake sees that this variable is set in @file{configure.in}, it
will check the @file{po} directory to ensure that all the named
@samp{.po} files exist, and that all the @samp{.po} files that exist are
named.
@cvindex ALL_LINGUAS

@item AM_C_PROTOTYPES
This is required when using automatic de-ANSI-fication, see @ref{ANSI}.
@cvindex AM_C_PROTOTYPES

@item AM_GNU_GETTEXT
This macro is required for packages which use GNU gettext
(@pxref{gettext}).  It is distributed with gettext.  If Automake sees
this macro it ensures that the package meets some of gettext's
requirements.
@cvindex AM_GNU_GETTEXT

@item AM_MAINTAINER_MODE
This macro adds a @samp{--enable-maintainer-mode} option to
@code{configure}.  If this is used, @code{automake} will cause
``maintainer-only'' rules to be turned off by default in the generated
@file{Makefile.in}s.  This macro is disallowed in @samp{Gnits} mode
(@pxref{Gnits}).
@cvindex AM_MAINTAINER_MODE

@item AC_SUBST
@itemx AC_CHECK_TOOL
@itemx AC_CHECK_PROG
@itemx AC_CHECK_PROGS
@itemx AC_PATH_PROG
@itemx AC_PATH_PROGS
For each of these macros, the first argument is automatically defined as
a variable in each generated @file{Makefile.in}.
@cvindex AC_SUBST
@cvindex AC_CHECK_TOOL
@cvindex AC_CHECK_PROG
@cvindex AC_CHECK_PROGS
@cvindex AC_PATH_PROG
@cvindex AC_PATH_PROGS

@end table


@node Invoking aclocal, Macros, Optional, configure
@section Auto-generating aclocal.m4

Automake includes a number of Autoconf macros which can be used in your
package; some of them are actually required by Automake in certain
situations.  These macros must be defined in your @file{aclocal.m4};
otherwise they will not be seen by @code{autoconf}.

The @code{aclocal} program will automatically generate @file{aclocal.m4}
files based on the contents of @file{configure.in}.  This provides a
convenient way to get Automake-provided macros, without having to
search around.  Also, the @code{aclocal} mechanism is extensible for use
by other packages.

At startup, @code{aclocal} scans all the @samp{.m4} files it can find,
looking for macro definitions.  Then it scans @file{configure.in}.  Any
mention of one of the macros found in the first step causes that macro,
and any macros it in turn requires, to be put into @file{aclocal.m4}.

The contents of @file{acinclude.m4}, if it exists, are also
automatically included in @file{aclocal.m4}.  This is useful for
incorporating local macros into @file{configure}.

@code{aclocal} accepts the following options:

@table @code
@item --acdir=@var{dir}
Look for the macro files in @var{dir} instead of the installation
directory.  This is typically used for debugging.

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

@item -I @var{dir}
Add the directory @var{dir} to the list of directories searched for
@samp{.m4} files.

@item --output=@var{file}
Cause the output to be put into @var{file} instead of @file{aclocal.m4}.

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

@item --version
Print the version number of Automake and exit.
@end table


@node Macros, Extending aclocal, Invoking aclocal, configure
@section Autoconf macros supplied with Automake

@c consider generating this node automatically from m4 files.

@table @code
@item AM_CONFIG_HEADER
Automake will generate rules to automatically regenerate the config
header.  If you do use this macro, you must create the file
@file{stamp-h.in} in your source directory.  It can be empty.
@cvindex AM_CONFIG_HEADER

@item AM_CYGWIN32
Check to see if this @code{configure} is being run in the
@samp{Cygwin32} environment.  (FIXME xref).  If so, define output
variable @code{EXEEXT} to @samp{.exe}; otherwise define it to the empty
string.  Automake recognizes this macro and uses it to generate
@file{Makefile.in}s which will automatically work under @samp{Cygwin32}.
In the @samp{Cygwin32} environment, @code{gcc} generates executables
whose names end in @samp{.exe}, even if this was not specified on the
command line.  Automake adds special code to @file{Makefile.in} to
gracefully deal with this.

@item AM_FUNC_STRTOD
If the @code{strtod} function is not available, or does not work
correctly (like the one on SunOS 5.4), add @file{strtod.o} to output
variable @code{LIBOBJS}.
@cvindex AM_FUNC_STRTOD

@item AM_FUNC_ERROR_AT_LINE
If the function @code{error_at_line} is not found, then add
@file{error.o} to @code{LIBOBJS}.
@cvindex AM_FUNC_ERROR_AT_LINE

@item AM_FUNC_MKTIME
Check for a working @code{mktime} function.  If not found, add
@file{mktime.o} to @samp{LIBOBJS}.
@cvindex AM_FUNC_MKTIME

@item AM_FUNC_OBSTACK
Check for the GNU obstacks code; if not found, add @file{obstack.o} to
@samp{LIBOBJS}.
@cvindex AM_FUNC_OBSTACK

@item AM_C_PROTOTYPES
Check to see if function prototypes are understood by the compiler.  If
so, define @samp{PROTOTYPES} and set the output variables @samp{U} and
@samp{ANSI2KNR} to the empty string.  Otherwise, set @samp{U} to
@samp{_} and @samp{ANSI2KNR} to @samp{./ansi2knr}.  Automake uses these
values to implement automatic de-ANSI-fication.
@cvindex AM_C_PROTOTYPES

@item AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL
If the use of @code{TIOCGWINSZ} requires @file{<sys/ioctl.h>}, then
define @code{GWINSZ_IN_SYS_IOCTL}.  Otherwise @code{TIOCGWINSZ} can be
found in @file{<termios.h>}.
@cvindex AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL

@item AM_INIT_AUTOMAKE
Runs many macros that most @file{configure.in}'s need.  This macro has
two required arguments, the package and the version number.  By default
this macro @code{AC_DEFINE}'s @samp{PACKAGE} and @samp{VERSION}.  This
can be avoided by passing in a non-empty third argument.

@item AM_PATH_LISPDIR
Searches for the program @code{emacs}, and, if found, sets the output
variable @code{lispdir} to the full path to Emacs' site-lisp directory.
@cvindex AM_PATH_LISPDIR

@item AM_PROG_CC_STDC
If the C compiler in not in ANSI C mode by default, try to add an option
to output variable @code{CC} to make it so.  This macro tries various
options that select ANSI C on some system or another.  It considers the
compiler to be in ANSI C mode if it handles function prototypes correctly.

If you use this macro, you should check after calling it whether the C
compiler has been set to accept ANSI C; if not, the shell variable
@code{am_cv_prog_cc_stdc} is set to @samp{no}.  If you wrote your source
code in ANSI C, you can make an un-ANSIfied copy of it by using the
@code{ansi2knr} option.
@cvindex AM_PROG_CC_STDC

@item AM_PROG_INSTALL
Like @code{AC_PROG_INSTALL}, but also defines @code{INSTALL_SCRIPT}.
@cvindex AM_PROG_INSTALL

@item AM_SANITY_CHECK
This checks to make sure that a file created in the build directory is
newer than a file in the source directory.  This can fail on systems
where the clock is set incorrectly.  This macro is automatically run
from @code{AM_INIT_AUTOMAKE}.
@cvindex AM_SANITY_CHECK

@item AM_SYS_POSIX_TERMIOS
Check to see if POSIX termios headers and functions are available on the
system.  If so, set the shell variable @code{am_cv_sys_posix_termios} to
@samp{yes}.  If not, set the variable to @samp{no}.
@cvindex AM_SYS_POSIX_TERMIOS

@item AM_TYPE_PTRDIFF_T
Define @samp{HAVE_PTRDIFF_T} if the type @samp{ptrdiff_t} is defined in
@file{<stddef.h>}.
@cvindex AM_TYPE_PTRDIFF_T

@item AM_WITH_DMALLOC
Add support for the @code{dmalloc} package.  If the user configures with
@samp{--with-dmalloc}, then define @code{WITH_DMALLOC} and add
@samp{-ldmalloc} to @code{LIBS}.  The @code{dmalloc} package can be
found at @url{ftp://ftp.letters.com/src/dmalloc/dmalloc.tar.gz}
@cvindex AM_WITH_DMALLOC

@item AM_WITH_REGEX
Adds @samp{--with-regex} to the @code{configure} command line.  If
specified (the default), then the @samp{regex} regular expression
library is used, @file{regex.o} is put into @samp{LIBOBJS}, and
@samp{WITH_REGEX} is defined..  If @samp{--without-regex} is given, then
the @samp{rx} regular expression library is used, and @file{rx.o} is put
into @samp{LIBOBJS}.
@cvindex AM_WITH_REGEX
@end table


@node Extending aclocal,  , Macros, configure
@section Writing your own aclocal macros

Aclocal doesn't have any built-in knowledge of any macros, so it is easy
to extend it with your own macros.

This is mostly used for libraries which want to supply their own
Autoconf macros for use by other programs.  For instance the
@code{gettext} library supplies a macro @code{AM_GNU_GETTEXT} which
should be used by any package using @code{gettext}.  When the library is
installed, it installs this macro so that @code{aclocal} will find it.

A file of macros should be a series of @code{AC_DEFUN}'s.  Aclocal also
understands @code{AC_REQUIRE}, so it is safe to put each macro in a
separate file.

A macro file's name should end in @samp{.m4}.  Such files should be
installed in @file{$(datadir)/aclocal}.

@node Top level, Programs, configure, Top
@chapter The top-level @file{Makefile.am}

In non-flat packages, the top level @file{Makefile.am} must tell
Automake which subdirectories are to be built.  This is done via the
@code{SUBDIRS} variable.
@vindex SUBDIRS

The @code{SUBDIRS} macro holds a list of subdirectories in which
building of various sorts can occur.  Many targets (eg @code{all}) in
the generated @file{Makefile} will run both locally and in all specified
subdirectories.  Note that the directories listed in @code{SUBDIRS} are
not required to contain @file{Makefile.am}s; only @file{Makefile}s
(after configuration).  This allows inclusion of libraries from packages
which do not use Automake (such as @code{gettext}).  The directories
mentioned in @code{SUBDIRS} must be direct children of the current
directory.  For instance, you cannot put @samp{src/subdir} into
@code{SUBDIRS}.

In a deep package, the top-level @file{Makefile.am} is often very short.
For instance, here is the @file{Makefile.am} from the Hello
distribution:

@example
EXTRA_DIST = BUGS ChangeLog.O README-alpha
SUBDIRS = doc intl po src tests
@end example

@code{SUBDIRS} can contain configure substitutions (eg @samp{@@DIRS@@});
Automake itself does not actually examine the contents of this variable.

If @code{SUBDIRS} is defined, then your @file{configure.in} must include
@code{AC_PROG_MAKE_SET}.

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


@node Programs, Other objects, Top level, Top
@chapter Building Programs and Libraries

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

@menu
* A Program::                   Building a program
* A Library::                   Building a library
* LIBOBJS::                     Special handling for LIBOBJS and ALLOCA
* A Shared Library::            Building a Libtool library
* Program variables::           Variables used when building a program
* Yacc and Lex::                Yacc and Lex support
* C++::                         
* ANSI::                        Automatic de-ANSI-fication
* Dependencies::                Automatic dependency tracking
@end menu


@node A Program, A Library, Programs, Programs
@section Building a program

In a directory containing source that gets built into a program (as
opposed to a library), the @samp{PROGRAMS} primary is used.  Programs
can be installed in @samp{bindir}, @samp{sbindir}, @samp{libexecdir},
@samp{pkglibdir}, or not at all (@samp{noinst}).

For instance:

@example
bin_PROGRAMS = hello
@end example

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

@example
hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h 
@end example

This causes each mentioned @samp{.c} file to be compiled into the
corresponding @samp{.o}.  Then all are linked to produce @file{hello}.

If @samp{prog_SOURCES} is needed, but not specified, then it defaults to
the single file @file{prog.c}.  In the example above, the definition of
@code{hello_SOURCES} is actually redundant.
@vindex _SOURCES
@vindex SOURCES

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
@samp{_SOURCES} definition.

Header files listed in a @samp{_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 @file{configure} in an
@samp{_SOURCES} variable; this file should not be distributed.  Lex
(@samp{.l}) and yacc (@samp{.y}) files can also be listed; see @ref{Yacc
and Lex}.

Automake must know all the source files that could possibly go into a
program, even if not all the files are built in every circumstance.
Any files which are only conditionally built should be listed in the
appropriate @samp{EXTRA_} variable.  For instance, if
@file{hello-linux.c} were conditionally included in @code{hello}, the
@file{Makefile.am} would contain:

@example
EXTRA_hello_SOURCES = hello-linux.c
@end example

Similarly, sometimes it is useful to determine the programs that are to
be built at configure time.  For instance, GNU @code{cpio} only builds
@code{mt} and @code{rmt} under special circumstances.

In this case, you must notify @code{automake} of all the programs that
can possibly be built, but at the same time cause the generated
@file{Makefile.in} to use the programs specified by @code{configure}.
This is done by having @code{configure} substitute values into each
@samp{_PROGRAMS} definition, while listing all optionally built programs in
@code{EXTRA_PROGRAMS}.
@vindex EXTRA_PROGRAMS

If you need to link against libraries that are not found by
@code{configure}, you can use @code{LDADD} to do so.  This variable
actually can be used to add any options to the linker command line.
@vindex LDADD

Sometimes, multiple programs are built in one directory but do not share
the same link-time requirements.  In this case, you can use the
@samp{@var{prog}_LDADD} variable (where @var{prog} is the name of the
program as it appears in some @samp{_PROGRAMS} variable, and usually
written in lowercase) to override the global @code{LDADD}.  (If this
variable exists for a given program, then that program is not linked
using @code{LDADD}.)
@vindex _LDADD

For instance, in GNU cpio, @code{pax}, @code{cpio}, and @code{mt} are
linked against the library @file{libcpio.a}.  However, @code{rmt} is
built in the same directory, and has no such link requirement.  Also,
@code{mt} and @code{rmt} are only built on certain architectures.  Here
is what cpio's @file{src/Makefile.am} looks like (abridged):

@example
bin_PROGRAMS = cpio pax @@MT@@
libexec_PROGRAMS = @@RMT@@
EXTRA_PROGRAMS = mt rmt

LDADD = ../lib/libcpio.a @@INTLLIBS@@
rmt_LDADD =

cpio_SOURCES = @dots{}
pax_SOURCES = @dots{}
mt_SOURCES = @dots{}
rmt_SOURCES = @dots{}
@end example

@samp{prog_LDADD} is inappropriate for passing program-specific linker
flags (except for @samp{-l} and @samp{-L}).  So, use the
@samp{prog_LDFLAGS} variable for this purpose.
@vindex _LDFLAGS

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 @samp{prog_DEPENDENCIES} variable.  Each program depends on
the contents of such a variable, but no further interpretation is done.

If @samp{prog_DEPENDENCIES} is not supplied, it is computed by Automake.
The automatically-assigned value is the contents of @samp{prog_LDADD},
with most configure substitutions, @samp{-l}, and @samp{-L} options
removed.  The configure substitutions that are left in are only
@samp{@@LIBOBJS@@} and @samp{@@ALLOCA@@}; these are left because it is
known that they will not cause an invalid value for
@samp{prog_DEPENDENCIES} to be generated.


@node A Library, LIBOBJS, A Program, Programs
@section Building a library

Building a library is much like building a program.  In this case, the
name of the primary is @samp{LIBRARIES}.  Libraries can be installed in
@code{libdir} or @code{pkglibdir}.

@xref{A Shared Library}, for information on how to build shared
libraries using Libtool and the @samp{LTLIBRARIES} primary.

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

@example
noinst_LIBRARIES = libcpio.a
@end example

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

Extra objects can be added to a library using the @samp{library_LIBADD}
variable.  This should be used for objects determined by
@code{configure}.  Again from cpio:
@vindex _LIBADD
@vindex LIBADD

@example
libcpio_a_LIBADD = @@LIBOBJS@@ @@ALLOCA@@
@end example

@node LIBOBJS, A Shared Library, A Library, Programs
@section Special handling for LIBOBJS and ALLOCA

Automake explicitly recognizes the use of @code{@@LIBOBJS@@} and
@code{@@ALLOCA@@}, and uses this information, plus the list of
@code{LIBOBJS} files derived from @file{configure.in} to automatically
include the appropriate source files in the distribution (@pxref{Dist}).
These source files are also automatically handled in the
dependency-tracking scheme, see @xref{Dependencies}.

@code{@@LIBOBJS@@} and @code{@@ALLOCA@@} are specially recognized in any
@samp{_LDADD} or @samp{_LIBADD} variable.

@node A Shared Library, Program variables, LIBOBJS, Programs
@section Building a Shared Library

Building shared libraries is a relatively complex matter.  For this
reason, GNU Libtool (@pxref{Top, , The Libtool Manual, libtool, The
Libtool Manual}) was created to help build shared libraries in a
platform-independent way.

Automake uses Libtool to build libraries declared with the
@samp{LTLIBRARIES} primary.  Each @samp{_LTLIBRARIES} variable is a list
of shared libraries to build.  For instance, to create a library named
@file{libgettext.a} and its corresponding shared libraries, and install
them in @samp{libdir}, write:

@example
lib_LTLIBRARIES = libgettext.la
@end example

Note that shared libraries @emph{must} be installed, so
@samp{noinst_LTLIBRARIES} and @samp{check_LTLIBRARIES} are not allowed.

For each library, the @samp{library_LIBADD} variable contains the names
of extra libtool objects (@samp{.lo} files) to add to the shared
library.  The @samp{library_LDFLAGS} variable contains any additional
libtool flags, such as @samp{-version-info} or @samp{-static}.

Where an ordinary library might include @code{@@LIBOBJS@@}, a libtool
library must use @code{@@LTLIBOBJS@@}.  This is required because the
object files that libtool operates on do not necessarily end in
@samp{.o}.  The libtool manual contains more details on this topic.

For libraries installed in some directory, @code{automake} will
automatically supply the appropriate @samp{-rpath} option.  However, for
libraries determined at configure time (and thus mentioned in
@code{EXTRA_LTLIBRARIES}), @code{automake} does not know the eventual
installation directory; for such libraries you must add the
@samp{-rpath} option to the appropriate @samp{_LDFLAGS} variable by
hand.

@xref{Using Automake, Using Automake with Libtool, The Libtool Manual,
libtool, The Libtool Manual}, for more information.

@node Program variables, Yacc and Lex, A Shared Library, Programs
@section Variables used when building a program

Occasionally it is useful to know which @file{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 @code{CC},
@code{CFLAGS}, @code{CPPFLAGS}, @code{DEFS}, @code{LDFLAGS}, and
@code{LIBS}.
@vindex LDFLAGS

There are some additional variables which Automake itself defines:

@table @code
@item INCLUDES
A list of @samp{-I} options.  This can be set in your @file{Makefile.am}
if you have special directories you want to look in.  @code{automake}
already provides some @samp{-I} options automatically.  In particular it
generates @samp{-I$(srcdir)} and a @samp{-I} pointing to the directory
holding @file{config.h} (if you've used @code{AC_CONFIG_HEADER} or
@code{AM_CONFIG_HEADER}).

@code{INCLUDES} can actually be used for other @code{cpp} options
besides @samp{-I}.  For instance, it is sometimes used to pass arbitrary
@samp{-D} options to the compiler.

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

@item LINK
This is the command used to actually link a C program.
@end table


@node Yacc and Lex, C++, Program variables, Programs
@section Yacc and Lex support

Automake has somewhat idiosyncratic support for Yacc and Lex.

Automake assumes that the @samp{.c} file generated by yacc (or lex)
should be named using the basename of the input file.  That is, for a
yacc source file @file{foo.y}, automake will cause the intermediate file
to be named @file{foo.c} (as opposed to @file{y.tab.c}, which is more
traditional).

The extension of a yacc source file is used to determine the extension
of the resulting @samp{C} or @samp{C++} file.  Files with the extension
@samp{.y} will be turned into @samp{.c} files; likewise, @samp{.yy} will
become @samp{.cc}; @samp{.y++}, @samp{c++}; and @samp{.yxx},
@samp{.cxx}.  Likewise, lex source files can be used to generate
@samp{C} or @samp{C++}; the extensions @samp{.l}, @samp{.ll},
@samp{.l++}, and @samp{.lxx} are recognized.

You should never explicitly mention the intermediate (@samp{C} or
@samp{C++}) file in any @samp{SOURCES} variable; only list the source
file.

The intermediate files generated by yacc (or lex) will be included in
any distribution that is made.  That way the user doesn't need to have
yacc or lex.

If a yacc source file is seen, then your @file{configure.in} must define
the variable @samp{YACC}.  This is most easily done by invoking the
macro @samp{AC_PROG_YACC}.

Similarly, if a lex source file is seen, then your @file{configure.in}
must define the variable @samp{LEX}.  You can use @samp{AC_PROG_LEX} to
do this.  Automake's lex support also requires that you use the
@samp{AC_DECL_YYTEXT} macro---automake needs to know the value of
@samp{LEX_OUTPUT_ROOT}.

Any program including a lex source file must be linked against
@samp{@@LEXLIB@@}.  You can do this by putting @samp{@@LEXLIB@@} into
the appropriate @samp{LDADD} variable.

Automake makes it possible to include multiple yacc (or lex) source
files in a single program.  Automake uses a small program called
@code{ylwrap} to run @code{yacc} (or @code{lex}) in a subdirectory.
This is necessary because yacc's output filename is fixed, and a
parallel make could conceivably invoke more than one instance of
@code{yacc} simultaneously.  @code{ylwrap} is distributed with automake.
It should appear in the directory specified by @samp{AC_CONFIG_AUX_DIR},
or the current directory if that macro is not used in
@file{configure.in}.

For @code{yacc}, simply managing locking is insufficient.  @code{yacc}
output also always uses the same symbol names internally, so it isn't
possible to link two @code{yacc} parsers into the same executable.

We recommend using the following renaming hack used in @code{gdb}:
@example
#define yymaxdepth c_maxdepth
#define yyparse c_parse
#define yylex   c_lex
#define yyerror c_error
#define yylval  c_lval
#define yychar  c_char
#define yydebug c_debug
#define yypact  c_pact  
#define yyr1    c_r1                    
#define yyr2    c_r2                    
#define yydef   c_def           
#define yychk   c_chk           
#define yypgo   c_pgo           
#define yyact   c_act           
#define yyexca  c_exca
#define yyerrflag c_errflag
#define yynerrs c_nerrs
#define yyps    c_ps
#define yypv    c_pv
#define yys     c_s
#define yy_yys  c_yys
#define yystate c_state
#define yytmp   c_tmp
#define yyv     c_v
#define yy_yyv  c_yyv
#define yyval   c_val
#define yylloc  c_lloc
#define yyreds  c_reds
#define yytoks  c_toks
#define yylhs   c_yylhs
#define yylen   c_yylen
#define yydefred c_yydefred
#define yydgoto c_yydgoto
#define yysindex c_yysindex
#define yyrindex c_yyrindex
#define yygindex c_yygindex
#define yytable  c_yytable
#define yycheck  c_yycheck
@end example

For each define, replace the @samp{c_} prefix with whatever you like.
These defines work for @code{bison}, @code{byacc}, and traditional
@code{yacc}s.  If you find a parser generator that uses a symbol not
covered here, please report the new name so it can be added to the list.


@node C++, ANSI, Yacc and Lex, Programs
@section 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 define the output variable
@samp{CXX} in @file{configure.in}; the simplest way to do this is to use
the @code{AC_PROG_CXX} macro.

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

@table @code
@item CXX
The name of the C++ compiler.
@vindex CXX

@item CXXFLAGS
Any flags to pass to the C++ compiler.
@vindex CXXFLAGS

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

@item CXXLINK
The command used to actually link a C++ program.
@vindex CXXLINK
@end table


@node ANSI, Dependencies, C++, Programs
@section Automatic de-ANSI-fication

Although the GNU standards allow the use of ANSI C, this can have the
effect of limiting portability of a package to some older compilers
(notably SunOS).

Automake allows you to work around this problem on such machines by
``de-ANSI-fying'' each source file before the actual compilation takes
place.

If the @file{Makefile.am} variable @code{AUTOMAKE_OPTIONS}
@vindex AUTOMAKE_OPTIONS
(@ref{Options}) contains the option @code{ansi2knr}
@opindex ansi2knr
then code to handle de-ANSI-fication is inserted into the generated
@file{Makefile.in}.

This causes each C source file in the directory to be treated as ANSI C.
If an ANSI C compiler is available, it is used.  If no ANSI C compiler
is available, the @code{ansi2knr} program is used to convert the source
files into K&R C, which is then compiled.

The @code{ansi2knr} program is simple-minded.  It assumes the source
code will be formatted in a particular way; see the @code{ansi2knr} man
page for details.

De-ANSI-fication support requires the source files @file{ansi2knr.c} and
@file{ansi2knr.1} to be in the same package as the ANSI C source; these
files are distributed with Automake.  Also, the package
@file{configure.in} must call the macro @code{AM_C_PROTOTYPES}.
@cvindex AM_C_PROTOTYPES

Automake also handles finding the @code{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 @code{ansi2knr}
option.  For instance, suppose the package has ANSI C code in the
@file{src} and @file{lib} subdirs.  The files @file{ansi2knr.c} and
@file{ansi2knr.1} appear in @file{lib}.  Then this could appear in
@file{src/Makefile.am}:

@example
AUTOMAKE_OPTIONS = ../lib/ansi2knr
@end example

If no directory prefix is given, the files are assumed to be in the
current directory.

@node Dependencies,  , ANSI, Programs
@section Automatic dependency tracking

As a developer it is often painful to continually update the
@file{Makefile.in} whenever the include-file dependencies change in a
project.  @code{automake} supplies a way to automatically track
dependency changes, and distribute the dependencies in the generated
@file{Makefile.in}.

Currently this support requires the use of GNU @code{make} and
@code{gcc}.  It might become possible in the future to supply a
different dependency generating program, if there is enough demand.  In
the meantime, this mode is enabled by default if any C program or
library is defined in the current directory, so you may get a @samp{Must
be a separator} error from non-GNU make.

When you decide to make a distribution, the @code{dist} target will
@trindex dist
re-run @code{automake} with @samp{--include-deps} and other options.
This will cause the previously generated dependencies to be inserted
into the generated @file{Makefile.in}, and thus into the distribution.
This step also turns off inclusion of the dependency generation code, so
that those who download your distribution but don't use GNU @code{make}
and @code{gcc} will not get errors.

When added to the @file{Makefile.in}, the dependencies have all
system-specific dependencies automatically removed.  This can be done by
listing the files in @samp{OMIT_DEPENDENCIES}.
@vindex OMIT_DEPENDENCIES
For instance all references to system header files are removed by
@code{automake}.  Sometimes it is useful to specify that a certain
header file should be removed.  For instance if your @file{configure.in}
uses @samp{AM_WITH_REGEX}, then any dependency on @file{rx.h} or
@file{regex.h} should be removed, because the correct one cannot be
known until the user configures the package.

As it turns out, @code{automake} is actually smart enough to handle the
particular case of the regular expression header.  It will also
automatically omit @file{libintl.h} if @samp{AM_GNU_GETTEXT} is used.

Automatic dependency tracking can be suppressed by putting
@code{no-dependencies} in the variable @code{AUTOMAKE_OPTIONS}.
@vindex AUTOMAKE_OPTIONS
@opindex no-dependencies

If you unpack a distribution made by @code{make dist}, and you want to
turn on the dependency-tracking code again, simply re-run
@code{automake}.

The actual dependency files are put under the build directory, in a
subdirectory named @file{.deps}.  These dependencies are machine
specific.  It is safe to delete them if you like; they will be
automatically recreated during the next build.


@node Other objects, Other GNU Tools, Programs, Top
@chapter 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.

@menu
* Scripts::                     Executable scripts
* Headers::                     Header files
* Data::                        Architecture-independent data files
* Sources::                     Derived sources
@end menu


@node Scripts, Headers, Other objects, Other objects
@section Executable Scripts

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

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

@code{automake} itself is a script that is generated at configure time
from @file{automake.in}.  Here is how this is handled:

@example
bin_SCRIPTS = automake
@end example

Since @code{automake} appears in the @code{AC_OUTPUT} macro, a target
for it is automatically generated.

Script objects can be installed in @code{bindir}, @code{sbindir},
@code{libexecdir}, or @code{pkgdatadir}.


@node Headers, Data, Scripts, Other objects
@section Header files

Header files are specified by the @samp{HEADERS} family of variables.
Generally header files are not installed, so the @code{noinst_HEADERS}
variable will be the most used.
@vindex HEADERS

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.  @xref{A Program}.  Headers
listed in a @samp{_SOURCES} variable need not be listed in any
@samp{_HEADERS} variable.

Headers can be installed in @code{includedir}, @code{oldincludedir}, or
@code{pkgincludedir}.


@node Data, Sources, Headers, Other objects
@section Architecture-independent data files

Automake supports the installation of miscellaneous data files using the
@samp{DATA} family of variables.
@vindex DATA

Such data can be installed in the directories @code{datadir},
@code{sysconfdir}, @code{sharedstatedir}, @code{localstatedir}, or
@code{pkgdatadir}.

By default, data files are not included in a distribution.

Here is how @code{automake} installs its auxiliary data files:

@example
pkgdata_DATA = clean-kr.am clean.am @dots{}
@end example


@node Sources,  , Data, Other objects
@section Built sources

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

Built sources are also not compiled by default.  You must either
explicitly mention them in some other @samp{_SOURCES} variable for this
to happen.

Note that, in some cases, @code{BUILT_SOURCES} will work in somewhat
suprising ways.  In order to get the built sources to work with
automatic dependency tracking, the @file{Makefile} must depend on
@code{$(BUILT_SOURCES)}.  This can cause these sources to be rebuilt at
what might seem like funny times.


@node Other GNU Tools, Documentation, Other objects, Top
@chapter Other GNU Tools

Since Automake is primarily intended to generate @file{Makefile.in}s for
use in GNU programs, it tries hard to interoperate with other GNU tools.

@menu
* Emacs Lisp::                  Emacs Lisp
* gettext::                     Gettext
* Guile::                       Guile
* Libtool::                     Libtool
@end menu

@node Emacs Lisp, gettext, Other GNU Tools, Other GNU Tools
@section Emacs Lisp

Automake provides some support for Emacs Lisp.  The @samp{LISP} primary
is used to hold a list of @samp{.el} files.  Possible prefixes for this
primary are @samp{lisp_} and @samp{noinst_}.  Note that if
@code{lisp_LISP} is defined, then @file{configure.in} must run
@code{AM_PATH_LISPDIR} (@pxref{Macros}).
@vindex LISP
@vindex lisp_LISP
@vindex noinst_LISP

By default Automake will byte-compile all Emacs Lisp source files using
the Emacs found by @code{AM_PATH_LISPDIR}.  If you wish to avoid
byte-compiling, simply define the variable @samp{ELCFILES} to be empty.
@vindex ELCFILES
Byte-compiled Emacs Lisp files are not portable among all versions of
Emacs, so it makes sense to turn this off if you expect sites to have
more than one version of Emacs installed.  Furthermore, many packages
don't actually benefit from byte-compilation.  Still, we recommand that
you leave it enabled by default.  It is probably better for sites with
strange setups to cope for themselves than to make the installation less
nice for everybody else.

@node gettext, Guile, Emacs Lisp, Other GNU Tools
@section Gettext

If @code{AM_GNU_GETTEXT} is seen in @file{configure.in}, then Automake
turns on support for GNU gettext, a message catalog system for
internationalization
(@pxref{GNU Gettext, , , gettext, GNU gettext utilities}).

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

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


@node Guile, Libtool, gettext, Other GNU Tools
@section Guile

Automake provides some automatic support for writing Guile modules.
Automake will turn on Guile support if the @code{AM_INIT_GUILE_MODULE}
macro is used in @file{configure.in}.

Right now Guile support just means that the @code{AM_INIT_GUILE_MODULE}
macro is understood to mean:
@itemize @bullet
@item
@code{AM_INIT_AUTOMAKE} is run.

@item
@code{AC_CONFIG_AUX_DIR} is run, with a path of @file{..}.
@end itemize

As the Guile module code matures, no doubt the Automake support will
grow as well.

@node Libtool,  , Guile, Other GNU Tools
@section Libtool

Automake provides support for GNU Libtool (@pxref{Top, , The Libtool
Manual, libtool, The Libtool Manual}) with the @samp{LTLIBRARIES}
primary.  @xref{A Shared Library}.

@node Documentation, Install, Other GNU Tools, Top
@chapter Building documentation

Currently Automake provides support for Texinfo and man pages.

@menu
* Texinfo::                     Texinfo
* Man pages::                   Man pages
@end menu


@node Texinfo, Man pages, Documentation, Documentation
@section Texinfo

If the current directory contains Texinfo source, you must declare it
with the @samp{TEXINFOS} primary.  Generally Texinfo files are converted
into info, and thus the @code{info_TEXINFOS} macro is most commonly used
here.  Note that any Texinfo source file must end in the @samp{.texi} or
@samp{.texinfo} extension.
@vindex TEXINFOS
@vindex info_TEXINFOS

If the @samp{.texi} file @code{@@include}s @file{version.texi}, then that
file will be automatically generated.  @file{version.texi} defines three
Texinfo macros you can reference: @code{EDITION}, @code{VERSION}, and
@code{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 @file{version.texi} support requires the
@code{mdate-sh} program; this program is supplied with Automake.

Sometimes an info file actually depends on more than one @samp{.texi}
file.  For instance, in GNU Hello, @file{hello.texi} includes the file
@file{gpl.texi}.  You can tell Automake about these dependencies using
the @samp{@var{texi}_TEXINFOS} variable.  Here is how Hello does it:
@vindex TEXINFOS
@vindex _TEXINFOS

@example
info_TEXINFOS = hello.texi
hello_TEXINFOS = gpl.texi
@end example

By default, Automake requires the file @file{texinfo.tex} to appear in
the same directory as the Texinfo source.  However, if you used
@code{AC_CONFIG_AUX_DIR} in @file{configure.in}, then @file{texinfo.tex}
is looked for there.  Automake supplies @file{texinfo.tex} if
@samp{--add-missing} is given.

If your package has Texinfo files in many directories, you can use the
variable @code{TEXINFO_TEX} to tell automake where to find the canonical
@file{texinfo.tex} for your package.  The value of this variable should
be the relative path from the current @file{Makefile.am} to
@file{texinfo.tex}:

@example
TEXINFO_TEX = ../doc/texinfo.tex
@end example

The option @samp{no-texinfo.tex} can be used to eliminate the
requirement for @file{texinfo.tex}.  Use of the variable
@code{TEXINFO_TEX} is preferable, however, because that allows the
@code{dvi} target to still work.

Automake generates an @code{install-info} target; some people apparently
use this.  By default, info pages are installed by @samp{make install}.
This can be prevented via the @code{no-installinfo} option.


@node Man pages,  , Texinfo, Documentation
@section Man pages

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

@c Use @samp{make install} per documentation: (texi)code.
By default, man pages are installed by @samp{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
@code{no-installman} option will prevent the man pages from being
installed by default.  The user can still explicitly install them via
@samp{make install-man}.
@opindex no-installman
@trindex install-man

Here is how the documentation is handled in GNU @code{cpio} (which
includes both Texinfo documentation and man pages):

@example
info_TEXINFOS = cpio.texi
man_MANS = cpio.1 mt.1
@end example

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

Man pages are not currently considered to be source, because it is not
uncommon for man pages to be automatically generated.


@node Install, Clean, Documentation, Top
@chapter What Gets Installed

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

Automake also handles installing any specified info and man pages.

Automake generates separate @code{install-data} and @code{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 @code{install} target depends on
both of these targets.
@trindex install-data
@trindex install-exec
@trindex install

Automake also generates an @code{uninstall} target, and an
@code{installdirs} target.
@trindex uninstall
@trindex installdirs

It is possible to extend this mechanism by defining an
@code{install-exec-local} or @code{install-data-local} target.  If these
targets exist, they will be run at @samp{make install} time.
@trindex install-exec-local
@trindex install-data-local

Variables using the standard directory prefixes @samp{data},
@samp{info}, @samp{man}, @samp{include}, @samp{oldinclude},
@samp{pkgdata}, or @samp{pkginclude} (eg @samp{data_DATA}) are installed
by @samp{install-data}.

Variables using the standard directory prefixes @samp{bin}, @samp{sbin},
@samp{libexec}, @samp{sysconf}, @samp{localstate}, @samp{lib}, or
@samp{pkglib} (eg @samp{bin_PROGRAMS}) are installed by
@samp{install-exec}.

Any variable using a user-defined directory prefix with @samp{exec} in
the name (eg @samp{myexecbin_PROGRAMS} is installed by
@samp{install-exec}.  All other user-defined prefixes are installed by
@samp{install-data}.


@node Clean, Dist, Install, Top
@chapter What Gets Cleaned

The GNU Makefile Standards specify a number of different clean rules.
@c FIXME xref
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
@code{MOSTLYCLEANFILES}, @code{CLEANFILES}, @code{DISTCLEANFILES}, and
@code{MAINTAINERCLEANFILES}.
@vindex MOSTLYCLEANFILES
@vindex CLEANFILES
@vindex DISTCLEANFILES
@vindex MAINTAINERCLEANFILES


@node Dist, Tests, Clean, Top
@chapter What Goes in a Distribution

The @code{dist} target in the generated @file{Makefile.in} can be used
to generate a gzip'd @code{tar} file for distribution.  The tar file is
named based on the @samp{PACKAGE} and @samp{VERSION} variables; more
precisely it is named @samp{@var{package}-@var{version}.tar.gz}.
@cvindex PACKAGE
@cvindex VERSION
@trindex dist

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 @file{Makefile.am}s and @file{Makefile.in}s.  Automake also
has a built-in list of commonly used files which, if present in the
current directory, are automatically included.  This list is printed by
@samp{automake --help}.  Also, files which are read by @code{configure}
(ie, the source files corresponding to the files specified in the
@code{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 @code{EXTRA_DIST} variable.  Note that @code{EXTRA_DIST} can only
handle files in the current directory; files in other directories will
cause @code{make dist} runtime failures.
@vindex EXTRA_DIST

If you define @code{SUBDIRS}, automake will recursively include the
subdirectories in the distribution.  If @code{SUBDIRS} is defined
conditionally (@pxref{Conditionals}), automake will normally include all
directories that could possibly appear in @code{SUBDIRS} in the
distribution.  If you need to specify the set of directories
conditionally, you can set the variable @code{DIST_SUBDIRS} to the exact
list of subdirectories to include in the distribution.
@vindex DIST_SUBDIRS

Occasionally it is useful to be able to change the distribution before
it is packaged up.  If the @code{dist-hook} target exists, it is run
after the distribution directory is filled, but before the actual tar
(or shar) file is created.  One way to use this is for distributing
files in subdirectories for which a new @file{Makefile.am} is overkill:

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

Automake also generates a @code{distcheck} target which can be help to
ensure that a given distribution will actually work.  @code{distcheck}
makes a distribution, and then tries to do a @code{VPATH} build.
@trindex distcheck
@c FIXME: document distcheck-hook here

@node Tests, Options, Dist, Top
@chapter Support for test suites

Automake supports a two forms of test suite.

If the variable @code{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 @var{srcdir} and @file{.}.

The number of failures will be printed at the end of the run.  If a
given test program exits with a status of 77, then its result is ignored
in the final count.  This feature allows non-portable tests to be
ignored in environments where they don't make sense.

The variable @code{TESTS_ENVIRONMENT} can be used to set environment
variables for the test run; the environment variable @code{srcdir} is
set in the rule.  If all your test programs are scripts, you can also
set @code{TESTS_ENVIRONMENT} to an invocation of the shell (eg
@samp{$(SHELL) -x}); this can be useful for debugging the tests.
@vindex TESTS
@vindex TESTS_ENVIRONMENT

If @samp{dejagnu} appears in @code{AUTOMAKE_OPTIONS}, then the a
@code{dejagnu}-based test suite is assumed.  The value of the variable
@code{DEJATOOL} is passed as the @code{--tool} argument to
@code{runtest}; it defaults to the name of the package.

The variable @code{RUNTESTDEFAULTFLAGS} holds the @code{--tool} and
@code{--srcdir} flags that are passed to dejagnu by default; this can be
overridden if necessary.
@vindex RUNTESTDEFAULTFLAGS

The variables @code{EXPECT}, @code{RUNTEST} and @code{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.
@opindex dejagnu
@vindex DEJATOOL
@vindex EXPECT
@vindex RUNTEST
@vindex RUNTESTFLAGS
@c FIXME xref dejagnu

In either case, the testing is done via @samp{make check}.


@node Options, Miscellaneous, Tests, Top
@chapter Changing Automake's Behavior

Various features of Automake can be controlled by options in the
@file{Makefile.am}.  Such options are listed in a special variable named
@code{AUTOMAKE_OPTIONS}.  Currently understood options are:
@vindex AUTOMAKE_OPTIONS

@table @asis
@item @code{gnits}
@itemx @code{gnu}
@itemx @code{foreign}
Set the strictness as appropriate.

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

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

@item @code{ansi2knr}
@itemx @code{path/ansi2knr}
Turn on automatic de-ANSI-fication.  @xref{ANSI}.  If preceeded by a
path, the generated @file{Makefile.in} will look in the specified
directory to find the @file{ansi2knr} program.  Generally the path
should be a relative path to another directory in the same distribution
(though Automake currently does not check this).

@item @code{dejagnu}
Cause @code{dejagnu}-specific rules to be generated.  @xref{Tests}.

@item @code{dist-shar}
Generate a @code{dist-shar} target as well as the ordinary @code{dist}
target.  This new target will create a shar archive of the
distribution.
@trindex dist-shar

@item @code{dist-zip}
Generate a @code{dist-zip} target as well as the ordinary @code{dist}
target.  This new target will create a zip archive of the distribution.
@trindex dist-zip

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

@item @code{no-dependencies}
This is similar to using @samp{--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 @xref{Dependencies}.  In this
case the effect is to effectively disable automatic dependency tracking.

@item @code{no-texinfo.tex}
Don't require @file{texinfo.tex}, even if there are texinfo files in
this directory.

@item @var{version}
A version number (eg @samp{0.30}) can be specified.  If Automake is not
newer than the version specified, creation of the @file{Makefile.in}
will be suppressed.
@end table

Unrecognized options are diagnosed by @code{automake}.


@node Miscellaneous, Conditionals, Options, Top
@chapter Miscellaneous Rules

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

@menu
* Tags::                        Interfacing to etags and mkid
* Suffixes::                    Handling new file extensions
@end menu


@node Tags, Suffixes, Miscellaneous, Miscellaneous
@section Interfacing to @code{etags}

@code{automake} will generate rules to generate @file{TAGS} files for
use with GNU Emacs under some circumstances.

If any C source code or headers are present, then @code{tags} and
@code{TAGS} targets will be generated for the directory.
@trindex tags

At the topmost directory of a multi-directory package, a @code{tags}
target file will be generated which, when run, will generate a
@file{TAGS} file that includes by reference all @file{TAGS} files from
subdirectories.

Also, if the variable @code{ETAGS_ARGS} is defined, a @code{tags} target
will be generated.  This variable is intended for use in directories
which contain taggable source that @code{etags} does not understand.
@vindex ETAGS_ARGS

Here is how Automake generates tags for its source, and for nodes in its
Texinfo file:

@example
ETAGS_ARGS = automake.in --lang=none \
 --regex='/^@@node[ \t]+\([^,]+\)/\1/' automake.texi
@end example

If you add filenames to @samp{ETAGS_ARGS}, you will probably also
want to set @samp{TAGS_DEPENDENCIES}.  The contents of this variable
are added directly to the dependencies for the @code{tags} target.
@vindex TAGS_DEPENDENCIES

Automake will also generate an @code{ID} target which will run
@code{mkid} on the source.  This is only supported on a
directory-by-directory basis.
@trindex id


@node Suffixes,  , Tags, Miscellaneous
@section 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 @code{SUFFIXES} variable.
@vindex SUFFIXES

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

@example
SUFFIXES = .java .class
@end example

@node Conditionals, Gnits, Miscellaneous, Top
@chapter Conditionals

Automake supports a simple type of conditionals.

@cvindex AM_CONDITIONAL
Before using a conditional, you must define it by using
@code{AM_CONDITIONAL} in the @code{configure.in} file.  The
@code{AM_CONDITIONAL} macro takes two arguments.

The first argument to @code{AM_CONDITIONAL} is the name of the
conditional.  This should be a simple string starting with a letter and
containing only letters, digits, and underscores.

The second argument to @code{AM_CONDITIONAL} is a shell condition,
suitable for use in a shell if statement.  The condition is evaluated
when @code{configure} is run.

Conditionals typically depend upon options which the user provides to
the @code{configure} script.  Here is an example of how to write a
conditional which is true if the user uses the @samp{--enable-debug}
option.

@example
AC_ARG_ENABLE(debug,
[  --enable-debug    Turn on debugging],
[case "$@{enableval@}" in
  yes) debug=true ;;
  no)  debug=false ;;
  *) AC_MSG_ERROR(bad value $@{enableval@} for --enable-debug) ;;
esac],[debug=false])
AM_CONDITIONAL(DEBUG, test x$debug = xtrue)
@end example

Here is an example of how to use that conditional in @file{Makefile.am}:

@example
if DEBUG
DBG = debug
else
DBG =
endif
noinst_PROGRAMS = $(DBG)
@end example

This trivial example could also be handled using EXTRA_PROGRAMS
(@pxref{A Program}).

You may only test a single variable in an @code{if} statement.  The
@code{else} statement may be omitted.  Conditionals may be nested to any
depth.

Note that conditionals in Automake are not the same as conditionals in
GNU Make.  Automake conditionals are checked at configure time by the
@file{configure} script, and affect the translation from
@file{Makefile.in} to @file{Makefile}.  They are based on options passed
to @file{configure} and on results that @file{configure} has discovered
about the host system.  GNU Make conditionals are checked at make time,
and are based on variables passed to the make program or defined in the
@file{Makefile}.

Automake conditionals will work with any make program.

@node Gnits, Cygnus, Conditionals, Top
@chapter The effect of @code{--gnu} and @code{--gnits}

The @samp{--gnu} option (or @samp{gnu} in the @samp{AUTOMAKE_OPTIONS}
variable) causes @code{automake} to check the following:

@itemize @bullet
@item
The files @file{INSTALL}, @file{NEWS}, @file{README}, @file{COPYING},
@file{AUTHORS}, and @file{ChangeLog} are required at the topmost
directory of the package.

@item
The options @samp{no-installman} and @samp{no-installinfo} are
prohibited.
@end itemize

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, @samp{--gnu} can require certain
non-standard GNU programs to exist for use by various maintainer-only
targets; for instance in the future @code{pathchk} might be required for
@samp{make dist}.

The @samp{--gnits} option does everything that @samp{--gnu} does, and
checks the following as well:

@itemize @bullet
@item
@samp{make dist} will check to make sure the @file{NEWS} file has been
updated to the current version.

@item
The file @file{COPYING.LIB} is prohibited.  The LGPL is apparently
considered a failed experiment.

@item
@samp{VERSION} is checked to make sure its format complies with Gnits
standards.
@c FIXME xref when standards are finished

@item
If @samp{VERSION} indicates that this is an alpha release, and the file
@file{README-alpha} appears in the topmost directory of a package, then
it is included in the distribution.  This is done in @samp{--gnits}
mode, and no other, because this mode is the only one where version
number formats are constrained, and hence the only mode where
@code{automake} can automatically determine whether @file{README-alpha}
should be included.

@item
The file @file{THANKS} is required.
@end itemize


@node Cygnus, Extending, Gnits, Top
@chapter The effect of @code{--cygnus}

Cygnus Solutions has slightly different rules for how a
@file{Makefile.in} is to be constructed.  Passing @samp{--cygnus} to
@code{automake} will cause any generated @file{Makefile.in} to comply
with Cygnus rules.

Here are the precise effects of @samp{--cygnus}:

@itemize @bullet
@item
Info files are always created in the build directory, and not in the
source directory.

@item
@file{texinfo.tex} is not required if a Texinfo source file is
specified.  The assumption is that the file will be supplied, but in a
place that @code{automake} cannot find.  This assumption is an artifact
of how Cygnus packages are typically bundled.

@item
@samp{make dist} will look for files in the build directory as well as
the source directory.  This is required to support putting info files
into the build directory.

@item
Certain tools will be searched for in the build tree as well as in the
user's @samp{PATH}.  These tools are @code{runtest}, @code{expect},
@code{makeinfo} and @code{texi2dvi}.

@item
@code{--foreign} is implied.

@item
The options @samp{no-installinfo} and @samp{no-dependencies} are
implied.

@item
The macros @samp{AM_MAINTAINER_MODE} and @samp{AM_CYGWIN32} are
required.

@item
The @code{check} target doesn't depend on @code{all}.
@end itemize

GNU maintainers are advised to use @samp{gnu} strictness in preference
to the special Cygnus mode.


@node Extending, Distributing, Cygnus, Top
@chapter When Automake Isn't Enough

Automake's implicit copying semantics means that many problems can be
worked around by simply adding some @code{make} targets and rules to
@file{Makefile.in}.  @code{automake} will ignore these additions.

There are some caveats to doing this.  Although you can overload a
target already used by @code{automake}, it is often inadvisable,
particularly in the topmost directory of a non-flat package.  However,
various useful targets have a @samp{-local} version you can specify in your
@file{Makefile.in}.  Automake will supplement the standard target with
these user-supplied targets.

The targets that support a local version are @code{all}, @code{info},
@code{dvi}, @code{check}, @code{install-data}, @code{install-exec},
@code{uninstall}, and the various @code{clean} targets
(@code{mostlyclean}, @code{clean}, @code{distclean}, and
@code{maintainer-clean}).  Note that there are no
@code{uninstall-exec-local} or @code{uninstall-data-local} targets; just
use @code{uninstall-local}.  It doesn't make sense to uninstall just
data or just executables.
@trindex all
@trindex info
@trindex dvi
@trindex check
@trindex install-data
@trindex install-exec
@trindex uninstall

For instance, here is one way to install a file in @file{/etc}:

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

Some targets also have a way to run another target, called a @dfn{hook},
after their work is done.  The hook is named after the principal target,
with @samp{-hook} appended.  The targets allowing hooks are
@code{install-data}, @code{install-exec}, @code{dist}, and
@code{distcheck}.
@trindex install-data-hook
@trindex install-exec-hook
@trindex dist-hook

For instance, here is how to create a hard link to an installed program:

@example
install-exec-hook:
        ln $(bindir)/program $(bindir)/proglink
@end example

@c FIXME should include discussion of variables you can use in these
@c rules


@node Distributing, Future, Extending, Top
@chapter Distributing @file{Makefile.in}s

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

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


@node Future, Index, Distributing, Top
@chapter Some ideas for the future

Here are some things that might happen in the future:

@itemize @bullet
@item
HTML support.

@item
The output will be cleaned up.  For instance, only variables which are
actually used will appear in the generated @file{Makefile.in}.

@item
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
@w{ISO 10646} with the UTF-8 encoding.

@item
Support for automatically generating packages (eg Debian packages, RPM
packages, Solaris packages, etc).  This will happen more quickly if
someone with package-building experience can tell me what would be
helpful.

@item
Rewrite in Guile.  This won't happen in the near future, but it will
eventually happen.
@end itemize

@node Index,  , Future, Top
@unnumbered Index

@printindex cp

@contents
@bye