source: vendor/automake/1.4-p6/automake.texi@ 3124

\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, 98 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 output variables.
@defcodeindex ov
@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 Define an index of commands.
@defcodeindex cm

@c Put the macros and variables into their own index.
@c @syncodeindex fn cp
@syncodeindex ov vr
@syncodeindex cv vr
@syncodeindex fn vr

@c Put everything else into one index (arbitrarily chosen to be the concept index).
@syncodeindex op cp
@syncodeindex tr cp
@syncodeindex cm 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
* Include::                     Including extra files in an Automake template.
* 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
* Macro and Variable Index::    
* General Index::               
@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.

@cindex 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 file 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.

@cindex Constraints of Automake
@cindex Automake constraints

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

@cindex Automake requirements
@cindex Requirements, Automake

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.

@cindex BUGS, reporting
@cindex Reporting BUGS
@cindex E-mail, bug reports

Mail suggestions and bug reports for Automake to
@email{bug-automake@@gnu.org}.


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

The following sections cover a few basic ideas that will help you
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 instance, a @samp{bin_PROGRAMS} macro definition will cause targets
for compiling and linking programs to be generated.

@cindex Non-standard targets
@cindex cvs-dist, non-standard example
@trindex cvs-dist

The macro definitions and targets in the @file{Makefile.am} are copied
verbatim 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.

@cindex GNU make extensions

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 and macro
definitions in an intelligent way.

@cindex Make targets, overriding
@cindex Overriding make targets

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.

@cindex Macros, overriding
@cindex Overriding make macros

Similarly, a macro defined in @file{Makefile.am} will override any
definition of the macro 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 macros generated by
@code{automake} are considered to be for internal use only, and their
names might change in future releases.

@cindex Recursive operation of Automake
@cindex Automake, recursive operation
@cindex Example of recursive operation

When examining a macro definition, Automake will recursively examine
macros referenced in the definition.  For example, if Automake is
looking at the content of @code{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 @code{foo_SOURCES}.

@cindex ## (special Automake comment)
@cindex Special Automake comment
@cindex Comment, special to Automake

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:

@cindex Makefile.am, first line
@cindex First line of Makefile.am

@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

@cindex Flat package
@cindex Package, Flat
@cindex Shallow package
@cindex Package, shallow
@cindex Deep package
@cindex Package, deep

@code{automake} supports three kinds of directory hierarchy:
@samp{flat}, @samp{shallow}, and @samp{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

@cindex SUBDIRS, deep package

A @dfn{deep} package is one in which all the source lies in
subdirectories; the top level directory contains mainly configuration
information.  GNU @code{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

@cindex Non-GNU packages

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.

@cindex Strictness, defined
@cindex Strictness, foreign
@cindex foreign strictness
@cindex Strictness, gnu
@cindex gnits strictness
@cindex Strictness, gnits
@cindex gnits strictness

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 @dfn{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 @ref{Gnits}.


@node Uniform, Canonicalization, Strictness, Generalities
@section The Uniform Naming Scheme

@cindex Uniform naming scheme

Automake macros (from here on referred to as @emph{variables}) generally
follow a @dfn{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.

@cindex _PROGRAMS primary variable
@cindex PROGRAMS primary variable
@cindex Primary variable, PROGRAMS

@cindex Primary variable, defined

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

@cindex pkglibdir, defined
@cindex pkgincludedir, defined
@cindex pkgdatadir, defined

@vindex pkglibdir
@vindex pkgincludedir
@vindex pkgdatadir

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

@cindex EXTRA_, prepending

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 that may be built in
order to generate a @file{Makefile.in} that will work in all cases.

@cindex EXTRA_PROGRAMS, defined
@cindex Example, EXTRA_PROGRAMS
@cindex cpio example

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 (e.g. @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.

@cindex Extending list of installation directories
@cindex Installation directories, extending list

Sometimes the standard directories---even as augmented by Automake---
are not enough.  In particular it is sometimes useful, for clarity, to
install objects in a subdirectory of some predefined directory.  To this
end, Automake allows you to extend the list of possible installation
directories.  A given prefix (e.g. @samp{zar}) is valid if a variable of
the same name with @samp{dir} appended is defined (e.g. @code{zardir}).

@cindex HTML support, example

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

@cindex noinst primary prefix, definition

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

@cindex check primary prefix, definition

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

@cindex canonicalizing Automake macros

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 macro naming rules.  All characters in the name except
for letters, numbers, and the underscore are turned into underscores
when making macro references.  For example, 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

@cindex Complete example

Let's suppose you just finished writing @code{zardoz}, a program to make
your head float from vortex to vortex.  You've been using 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 Automake.

@cindex AM_INIT_AUTOMAKE, example use

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 just after @code{AC_INIT}:

@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!

@cindex aclocal program, introduction
@cindex aclocal.m4, preexisting
@cindex acinclude.m4, defined

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.  The @code{aclocal} program 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

@cindex zardoz example

Now it is time to write your @file{Makefile.am} for @code{zardoz}.
Since @code{zardoz} is a user program, you want to install it where the
rest of the user programs go.  Additionally, @code{zardoz} 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

@cindex Example, GNU Hello
@cindex Hello example
@cindex GNU Hello, example

@uref{ftp://prep.ai.mit.edu/pub/gnu/hello-1.3.tar.gz, GNU hello} is
renowned for its classic simplicity and versatility.  This section shows
how Automake could be used with the GNU Hello package.  The examples
below are from the latest beta version of GNU Hello, but with all of the
maintainer-only code stripped out, as well as all copyright comments.

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

@cindex configure.in, from GNU Hello
@cindex GNU Hello, configure.in
@cindex Hello, configure.in

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.

@cindex Texinfo file handling example
@cindex Example, handling Texinfo files

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 GNU Hello
manual.

@cindex Regression test example
@cindex Example, regression test

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.

@cindex INCLUDES, example usage

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

@cindex Example, ctags and etags
@cindex ctags Example
@cindex etags Example

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 (@pxref{ANSI}).  Supporting de-ANSI-fication 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}

@cindex Multiple configure.in files
@cindex Invoking Automake
@cindex Automake, invoking

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; @file{.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.

@cindex Automake options
@cindex Options, Automake

@code{automake} accepts the following options:

@cindex Extra files distributed with Automake
@cindex Files distributed with Automake
@cindex config.guess

@table @samp
@item -a
@itemx --add-missing
@opindex -a
@opindex --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.  By default Automake tries to
make a symbolic link pointing to its own copy of the missing file; this
can be changed with @code{--copy}.

@item --amdir=@var{dir}
@opindex --amdir
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}
@opindex --build-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 -c
@item --copy
When used with @code{--add-missing}, causes installed files to be
copied.  The default is to make a symbolic link.

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

@item --foreign
@opindex --foreign
Set the global strictness to @samp{foreign}.  For more information, see
@ref{Strictness}.

@item --gnits
@opindex --gnits
Set the global strictness to @samp{gnits}.  For more information, see
@ref{Gnits}.

@item --gnu
@opindex --gnu
Set the global strictness to @samp{gnu}.  For more information, see
@ref{Gnits}.  This is the default strictness.

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

@item -i
@itemx --include-deps
@opindex -i
@opindex --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 --generate-deps
@opindex --generate-deps
Generate a file concatenating all automatically generated dependency
information (@pxref{Dependencies}) into one file, @file{.dep_segment}.
This is generally done when making a distribution; see @ref{Dist}.  It
is useful when maintaining a @file{SMakefile} or makefiles for other
platforms (@file{Makefile.DOS}, etc.)  It can only be used in
conjunction with @samp{--include-deps}, @samp{--srcdir-name}, and
@samp{--build-dir}.  Note that if this option is given, no other
processing is done.

@item --no-force
@opindex --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}
@opindex -o
@opindex --output-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}
@opindex --srcdir-name
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
@opindex -v
@opindex --verbose
Cause Automake to print information about which files are being read or
created.

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


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

@cindex configure.in, scanning
@cindex Scanning 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 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

@cindex Automake requirements
@cindex Requirements of Automake

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.
@xref{Transforming Names, , Transforming Program Names When Installing,
autoconf, The Autoconf}.
@cvindex AC_ARG_PROGRAM

@item
Use @code{AC_PROG_MAKE_SET} if the package is not flat.  @xref{Output, ,
Creating Output Files, autoconf, The Autoconf Manual}.
@cvindex AC_PROG_MAKE_SET

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

@item
Call @code{AC_PROG_INSTALL}
(@pxref{Particular Programs, , Particular Program Checks, autoconf, The
Autoconf Manual}).
@cvindex AC_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}:

@cindex AC_OUTPUT, scanning

@table @code
@item AC_OUTPUT
Automake uses this to determine which files to create (@pxref{Output, ,
Creating Output Files, autoconf, The Autoconf Manual}).  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

@cindex Macros Automake recognizes
@cindex Recognized macros by Automake

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} (@pxref{Configuration Headers, ,
Configuration Header Files, autoconf, The Autoconf Manual}), 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 @samp{standard}
locations (either the top source directory, or in the source directory
corresponding to the current @file{Makefile.am}, whichever is
appropriate).  @xref{Input, , Finding `configure' Input, autoconf, The
Autoconf Manual}.
@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.  @xref{System Services, , System Services, autoconf, The
Autoconf Manual}.
@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.  See both @ref{Canonicalizing, ,
Getting the Canonical System Type, autoconf, The Autoconf Manual}, and
@ref{Generic Programs, , Generic Program Checks, autoconf, The Autoconf
Manual}.
@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}.
@xref{Canonicalizing, , Getting the Canonical System Type, autoconf, The
Autoconf Manual}.
@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.  Also, see @ref{Particular
Functions, , Particular Function Checks, autoconf, The Autoconf Manual}.
@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 @file{.o} files into
@code{LIBOBJS}, and will treat these additional files as if they were
discovered via @code{AC_REPLACE_FUNCS}.  @xref{Generic Functions, ,
Generic Function Checks, autoconf, The Autoconf Manual}.
@cvindex LIBOBJS

@item AC_PROG_RANLIB
This is required if any libraries are built in the package.
@xref{Particular Programs, , Particular Program Checks, autoconf, The
Autoconf Manual}.
@cvindex AC_PROG_RANLIB

@item AC_PROG_CXX
This is required if any C++ source is included.  @xref{Particular
Programs, , Particular Program Checks, autoconf, The Autoconf Manual}.
@cvindex AC_PROG_CXX

@item AC_PROG_F77
This is required if any Fortran 77 source is included.  This macro is
distributed with Autoconf version 2.13 and later.  @xref{Particular
Programs, , Particular Program Checks, autoconf, The Autoconf Manual}.
@cvindex AC_PROG_F77

@item AC_F77_LIBRARY_LDFLAGS
This is required for programs and shared libraries that are a mixture of
languages that include Fortran 77 (@pxref{Mixing Fortran 77 With C and
C++}).  @xref{Macros, , Autoconf macros supplied with Automake}.
@cvindex AC_F77_LIBRARY_LDFLAGS

@item AM_PROG_LIBTOOL
Automake will turn on processing for @code{libtool} (@pxref{Top, ,
Introduction, 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 (@pxref{Particular Programs, , Particular Program Checks,
autoconf, The Autoconf Manual}).
@cvindex AC_PROG_YACC
@cvindex YACC

@item AC_DECL_YYTEXT
This macro is required if there is Lex source in the package.
@xref{Particular Programs, , Particular Program Checks, autoconf, The
Autoconf Manual}.
@cvindex AC_DECL_YYTEXT

@item AC_PROG_LEX
If a Lex source file is seen, then this macro must be used.
@xref{Particular Programs, , Particular Program Checks, autoconf, The
Autoconf Manual}.
@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
@opindex --enable-maintainer-mode
This macro adds a @samp{--enable-maintainer-mode} option to
@code{configure}.  If this is used, @code{automake} will cause
@samp{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}).  This macro defines the @samp{MAINTAINER_MODE}
conditional, which you can use in your own @file{Makefile.am}.
@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}.  @xref{Setting Output
Variables, , Setting Output Variables, autoconf, The Autoconf Manual},
and @ref{Generic Programs, , Generic Program Checks, autoconf, The
Autoconf Manual}.
@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

@cindex Invoking aclocal
@cindex aclocal, Invoking

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 @file{.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}
@opindex --acdir
Look for the macro files in @var{dir} instead of the installation
directory.  This is typically used for debugging.

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

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

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

@item --print-ac-dir
@opindex --print-ac-dir
Prints the name of the directory which @code{aclocal} will search to
find the @file{.m4} files.  When this option is given, normal processing
is suppressed.  This option can be used by a package to determine where
to install a macro file.

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

@item --version
@opindex --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_ENABLE_MULTILIB
This is used when a ``multilib'' library is being built.  A
@dfn{multilib} library is one that is built multiple times, once per
target flag combination.  This is only useful when the library is
intended to be cross-compiled.  The first optional argument is the name
of the @file{Makefile} being generated; it defaults to @samp{Makefile}.
The second option argument is used to find the top source directory; it
defaults to the empty string (generally this should not be used unless
you are familiar with the internals).

@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 (@pxref{ANSI}).

@item AM_PROG_LEX
@cindex HP-UX 10, lex problems
@cindex lex problems with HP-UX 10
Like @code{AC_PROG_LEX} with @code{AC_DECL_YYTEXT} (@pxref{Particular
Programs, , Particular Program Checks, autoconf, The Autoconf Manual}),
but uses the @code{missing} script on systems that do not have
@code{lex}.  @samp{HP-UX 10} is one such system.

@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}.

@item AM_SYS_POSIX_TERMIOS
@cvindex am_cv_sys_posix_termios
@cindex POSIX termios headers
@cindex termios POSIX headers
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}.

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

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

@item AM_WITH_REGEX
@cvindex WITH_REGEX
@opindex --with-regex
@cindex regex package
@cindex rx package
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}.

@end table


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

@cindex aclocal, extending
@cindex Extending aclocal

The @code{aclocal} program doesn't have any built-in knowledge of any
macros, so it is easy to extend it with your own macros.

This is mostly used for libraries which want to supply their own
Autoconf macros for use by other programs.  For instance the
@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.  The
@code{aclocal} programs also understands @code{AC_REQUIRE}, so it is
safe to put each macro in a separate file.  @xref{Prerequisite Macros, ,
, autoconf, The Autoconf Manual}, and @ref{Macro Definitions, , ,
autoconf, The Autoconf Manual}.

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


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

@cindex SUBDIRS, explained

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 (e.g. @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 GNU Hello
distribution:

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

@cindex SUBDIRS, overriding
@cindex Overriding SUBDIRS

It is possible to override the @code{SUBDIRS} variable if, like in the
case of GNU @code{Inetutils}, you want to only build a subset of the
entire package.  In your @file{Makefile.am} include:

@example
SUBDIRS = @@SUBDIRS@@
@end example

Then in your @file{configure.in} you can specify:

@example
SUBDIRS = "src doc lib po"
AC_SUBST(SUBDIRS)
@end example

The upshot of this is that Automake is tricked into building the package
to take the subdirs, but doesn't actually bind that list until
@code{configure} is run.

Although the @code{SUBDIRS} macro can contain configure substitutions
(e.g. @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.

By default, Automake generates @file{Makefiles} which work depth-first
(@samp{postfix}).  However, it is possible to change this ordering.  You
can do this by putting @samp{.} into @code{SUBDIRS}.  For instance,
putting @samp{.}  first will cause a @samp{prefix} ordering of
directories.


@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 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++ Support::                 
* Fortran 77 Support::          
* Support for Other Languages::  
* ANSI::                        Automatic de-ANSI-fication
* Dependencies::                Automatic dependency tracking
@end menu


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

@cindex PROGRAMS, bindir
@vindex bin_PROGRAMS
@vindex sbin_PROGRAMS
@vindex libexec_PROGRAMS
@vindex pkglib_PROGRAMS
@vindex noinst_PROGRAMS

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 @code{bindir}, @code{sbindir}, @code{libexecdir},
@code{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}.

@cindex _SOURCES primary, defined
@cindex SOURCES primary, defined
@cindex Primary variable, SOURCES

If @samp{@var{prog}_SOURCES} is needed, but not specified, then it
defaults to the single file @file{prog.c}.
@vindex _SOURCES
@vindex SOURCES

Multiple programs can be built in a single directory.  Multiple programs
can share a single source file, which must be listed in each
@samp{_SOURCES} definition.

@cindex Header files in _SOURCES
@cindex _SOURCES and header files

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}.

@cindex EXTRA_prog_SOURCES, defined

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.

@cindex EXTRA_PROGRAMS, defined

In this case, you must notify 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

@cindex prog_LDADD, defined

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

@cindex _LDFLAGS, defined

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

@cindex _DEPENDENCIES, defined

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

If @samp{@var{prog}_DEPENDENCIES} is not supplied, it is computed by
Automake.  The automatically-assigned value is the contents of
@samp{@var{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{@var{prog}_DEPENDENCIES} to be generated.


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

@cindex _LIBRARIES primary, defined
@cindex LIBRARIES primary, defined
@cindex Primary variable, LIBRARIES

@vindex lib_LIBRARIES
@vindex pkglib_LIBRARIES
@vindex noinst_LIBRARIES

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}.

@cindex _LIBADD primary, defined
@cindex LIBADD primary, defined
@cindex Primary variable, LIBADD

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

@cindex @@LIBOBJS@@, special handling
@cindex @@ALLOCA@@, special handling

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

@cindex Shared libraries, support for

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

@cindex _LTLIBRARIES primary, defined
@cindex LTLIBRARIES primary, defined
@cindex Primary variable, LTLIBRARIES
@cindex Example of shared libraries

@cindex suffix .la, defined

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

@vindex lib_LTLIBRARIES
@vindex pkglib_LTLIBRARIES
@vindex noinst_LTLIBRARIES
@vindex check_LTLIBRARIES

@cindex check_LTLIBRARIES, not allowed

Note that shared libraries @emph{must} be installed, so
@code{check_LTLIBRARIES} is not allowed.  However,
@code{noinst_LTLIBRARIES} is allowed.  This feature should be used for
libtool ``convenience libraries''.

@cindex suffix .lo, defined

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

@cindex @@LTLIBOBJS@@, special handling

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
@file{.o}.  The libtool manual contains more details on this topic.

For libraries installed in some directory, Automake will automatically
supply the appropriate @samp{-rpath} option.  However, for libraries
determined at configure time (and thus mentioned in
@code{EXTRA_LTLIBRARIES}), 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:

@vtable @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.  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 vtable


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

Automake has somewhat idiosyncratic support for Yacc and Lex.

Automake assumes that the @file{.c} file generated by @code{yacc} (or
@code{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 @code{yacc} (or @code{lex}) will be
included in any distribution that is made.  That way the user doesn't
need to have @code{yacc} or @code{lex}.

If a @code{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} (@pxref{Particular Programs, , Particular
Program Checks, autoconf, The Autoconf Manual}).

Similarly, if a @code{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 (@pxref{Particular Programs, , Particular
Program Checks, autoconf, The Autoconf Manual}).  Automake's @code{lex}
support also requires that you use the @samp{AC_DECL_YYTEXT}
macro---automake needs to know the value of @samp{LEX_OUTPUT_ROOT}.
This is all handled for you if you use the @code{AM_PROG_LEX} macro
(@pxref{Macros}).

@cindex ylwrap
@cindex yacc, multiple parsers
@cindex Multiple yacc parsers
@cindex Multiple lex lexers
@cindex lex, multiple lexers


Automake makes it possible to include multiple @code{yacc} (or
@code{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.  The @code{ylwrap} program is
distributed with Automake.  It should appear in the directory specified
by @samp{AC_CONFIG_AUX_DIR} (@pxref{Input, , Finding `configure' Input,
autoconf, The Autoconf Manual}), or the current directory if that macro
is not used in @file{configure.in}.

For @code{yacc}, simply managing locking is insufficient.  The output of
@code{yacc} 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
#define yyname   c_yyname
#define yyrule   c_yyrule
@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++ Support, Fortran 77 Support, Yacc and Lex, Programs
@section C++ Support

@cindex C++ support
@cindex Support for C++

Automake includes full support for C++.

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 (@pxref{Particular Programs, , Particular
Program Checks, autoconf, The Autoconf Manual}).

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

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

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

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

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


@node Fortran 77 Support, Support for Other Languages, C++ Support, Programs
@comment  node-name,  next,  previous,  up
@section Fortran 77 Support

@cindex Fortran 77 support
@cindex Support for Fortran 77

Automake includes full support for Fortran 77.

Any package including Fortran 77 code must define the output variable
@samp{F77} in @file{configure.in}; the simplest way to do this is to use
the @code{AC_PROG_F77} macro (@pxref{Particular Programs, , Particular
Program Checks, autoconf, The Autoconf Manual}).  @xref{Fortran 77 and
Autoconf}.

A few additional variables are defined when a Fortran 77 source file is
seen:

@vtable @code

@item F77
The name of the Fortran 77 compiler.

@item FFLAGS
Any flags to pass to the Fortran 77 compiler.

@item RFLAGS
Any flags to pass to the Ratfor compiler.

@item F77COMPILE
The command used to actually compile a Fortran 77 source file.  The file
name is appended to form the complete command line.

@item FLINK
The command used to actually link a pure Fortran 77 program or shared
library.

@end vtable

Automake can handle preprocessing Fortran 77 and Ratfor source files in
addition to compiling them@footnote{Much, if not most, of the
information in the following sections pertaining to preprocessing
Fortran 77 programs was taken almost verbatim from @ref{Catalogue of
Rules, , Catalogue of Rules, make, The GNU Make Manual}.}.  Automake
also contains some support for creating programs and shared libraries
that are a mixture of Fortran 77 and other languages (@pxref{Mixing
Fortran 77 With C and C++}).

These issues are covered in the following sections.

@menu
* Preprocessing Fortran 77::    
* Compiling Fortran 77 Files::  
* Mixing Fortran 77 With C and C++::  
* Fortran 77 and Autoconf::     
@end menu


@node Preprocessing Fortran 77, Compiling Fortran 77 Files, Fortran 77 Support, Fortran 77 Support
@comment  node-name,  next,  previous,  up
@subsection Preprocessing Fortran 77

@cindex Preprocessing Fortran 77
@cindex Fortran 77, Preprocessing
@cindex Ratfor programs

@file{N.f} is made automatically from @file{N.F} or @file{N.r}.  This
rule runs just the preprocessor to convert a preprocessable Fortran 77
or Ratfor source file into a strict Fortran 77 source file.  The precise
command used is as follows:

@table @file

@item .F
@code{$(F77) -F $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_FFLAGS) $(FFLAGS)}

@item .r
@code{$(F77) -F $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)}

@end table


@node Compiling Fortran 77 Files, Mixing Fortran 77 With C and C++, Preprocessing Fortran 77, Fortran 77 Support
@comment  node-name,  next,  previous,  up
@subsection Compiling Fortran 77 Files

@file{N.o} is made automatically from @file{N.f}, @file{N.F} or
@file{N.r} by running the Fortran 77 compiler.  The precise command used
is as follows:

@table @file

@item .f
@code{$(F77) -c $(AM_FFLAGS) $(FFLAGS)}

@item .F
@code{$(F77) -c $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_FFLAGS) $(FFLAGS)}

@item .r
@code{$(F77) -c $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)}

@end table


@node Mixing Fortran 77 With C and C++, Fortran 77 and Autoconf, Compiling Fortran 77 Files, Fortran 77 Support
@comment  node-name,  next,  previous,  up
@subsection Mixing Fortran 77 With C and C++

@cindex Fortran 77, mixing with C and C++
@cindex Mixing Fortran 77 with C and C++
@cindex Linking Fortran 77 with C and C++
@cindex cfortran
@cindex Mixing Fortran 77 with C and/or C++

Automake currently provides @emph{limited} support for creating programs
and shared libraries that are a mixture of Fortran 77 and C and/or C++.
However, there are many other issues related to mixing Fortran 77 with
other languages that are @emph{not} (currently) handled by Automake, but
that are handled by other packages@footnote{For example,
@uref{http://www-zeus.desy.de/~burow/cfortran/, the cfortran package}
addresses all of these inter-language issues, and runs under nearly all
Fortran 77, C and C++ compilers on nearly all platforms.  However,
@code{cfortran} is not yet Free Software, but it will be in the next
major release.}.

@page
Automake can help in two ways:

@enumerate
@item
Automatic selection of the linker depending on which combinations of
source code.

@item
Automatic selection of the appropriate linker flags (e.g. @samp{-L} and
@samp{-l}) to pass to the automatically selected linker in order to link
in the appropriate Fortran 77 intrinsic and run-time libraries.

@cindex FLIBS, defined
These extra Fortran 77 linker flags are supplied in the output variable
@code{FLIBS} by the @code{AC_F77_LIBRARY_LDFLAGS} Autoconf macro
supplied with newer versions of Autoconf (Autoconf version 2.13 and
later).  @xref{Fortran 77 Compiler Characteristics, , , autoconf, The
Autoconf}.
@end enumerate

If Automake detects that a program or shared library (as mentioned in
some @code{_PROGRAMS} or @code{_LTLIBRARIES} primary) contains source
code that is a mixture of Fortran 77 and C and/or C++, then it requires
that the macro @code{AC_F77_LIBRARY_LDFLAGS} be called in
@file{configure.in}, and that either @code{$(FLIBS)} or @code{@@FLIBS@@}
appear in the appropriate @code{_LDADD} (for programs) or @code{_LIBADD}
(for shared libraries) variables.  It is the responsibility of the
person writing the @file{Makefile.am} to make sure that @code{$(FLIBS)}
or @code{@@FLIBS@@} appears in the appropriate @code{_LDADD} or
@code{_LIBADD} variable.

@cindex Mixed language example
@cindex Example, mixed language

For example, consider the following @file{Makefile.am}:

@example
bin_PROGRAMS = foo
foo_SOURCES  = main.cc foo.f
foo_LDADD    = libfoo.la @@FLIBS@@

pkglib_LTLIBRARIES = libfoo.la
libfoo_la_SOURCES  = bar.f baz.c zardoz.cc
libfoo_la_LIBADD   = $(FLIBS)
@end example

In this case, Automake will insist that @code{AC_F77_LIBRARY_LDFLAGS}
is mentioned in @file{configure.in}.  Also, if @code{@@FLIBS@@} hadn't
been mentioned in @code{foo_LDADD} and @code{libfoo_la_LIBADD}, then
Automake would have issued a warning.


@page
@menu
* How the Linker is Chosen::    
@end menu

@node How the Linker is Chosen,  , Mixing Fortran 77 With C and C++, Mixing Fortran 77 With C and C++
@comment  node-name,  next,  previous,  up
@subsubsection How the Linker is Chosen

@cindex Automatic linker selection
@cindex Selecting the linker automatically

The following diagram demonstrates under what conditions a particular
linker is chosen by Automake.

For example, if Fortran 77, C and C++ source code were to be compiled
into a program, then the C++ linker will be used.  In this case, if the
C or Fortran 77 linkers required any special libraries that weren't
included by the C++ linker, then they must be manually added to an
@code{_LDADD} or @code{_LIBADD} variable by the user writing the
@file{Makefile.am}.

@example
                     \              Linker
          source      \
           code        \     C        C++     Fortran
     -----------------  +---------+---------+---------+
                        |         |         |         |
     C                  |    x    |         |         |
                        |         |         |         |
                        +---------+---------+---------+
                        |         |         |         |
         C++            |         |    x    |         |
                        |         |         |         |
                        +---------+---------+---------+
                        |         |         |         |
               Fortran  |         |         |    x    |
                        |         |         |         |
                        +---------+---------+---------+
                        |         |         |         |
     C + C++            |         |    x    |         |
                        |         |         |         |
                        +---------+---------+---------+
                        |         |         |         |
     C +       Fortran  |         |         |    x    |
                        |         |         |         |
                        +---------+---------+---------+
                        |         |         |         |
         C++ + Fortran  |         |    x    |         |
                        |         |         |         |
                        +---------+---------+---------+
                        |         |         |         |
     C + C++ + Fortran  |         |    x    |         |
                        |         |         |         |
                        +---------+---------+---------+
@end example


@node Fortran 77 and Autoconf,  , Mixing Fortran 77 With C and C++, Fortran 77 Support
@comment  node-name,  next,  previous,  up
@subsection Fortran 77 and Autoconf

The current Automake support for Fortran 77 requires a recent enough
version Autoconf that also includes support for Fortran 77.  Full
Fortran 77 support was added to Autoconf 2.13, so you will want to use
that version of Autoconf or later.


@node Support for Other Languages, ANSI, Fortran 77 Support, Programs
@comment  node-name,  next,  previous,  up
@section Support for Other Languages

Automake currently only includes full support for C, C++ (@pxref{C++
Support})and Fortran 77 (@pxref{Fortran 77 Support}).  There is only
rudimentary support for other languages, support for which will be
improved based on user demand.


@node ANSI, Dependencies, Support for Other Languages, Programs
@section Automatic de-ANSI-fication

@cindex de-ANSI-fication, defined

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
@dfn{de-ANSI-fying} each source file before the actual compilation takes
place.

@vindex AUTOMAKE_OPTIONS
@opindex ansi2knr

If the @file{Makefile.am} variable @code{AUTOMAKE_OPTIONS}
(@pxref{Options}) contains the option @code{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.

Support for de-ANSI-fication 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}
(@pxref{Macros}).
@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.

Files mentioned in @code{LIBOBJS} which need de-ANSI-fication will not
be automatically handled.  That's because @code{configure} will generate
an object name like @file{regex.o}, while @code{make} will be looking
for @file{regex_.o} (when de-ANSI-fying).  Eventually this problem will
be fixed via @code{autoconf} magic, but for now you must put this code
into your @file{configure.in}, just before the @code{AC_OUTPUT} call:

@example
# This is necessary so that .o files in LIBOBJS are also built via
# the ANSI2KNR-filtering rules.
LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
@end example


@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.  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.

@trindex dist

When you decide to make a distribution, the @code{dist} target will
re-run @code{automake} with @samp{--include-deps} and other options.
@xref{Invoking Automake}, and @ref{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.

@vindex OMIT_DEPENDENCIES

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}.  For instance all
references to system header files are removed by 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, 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.

@vindex AUTOMAKE_OPTIONS
@opindex no-dependencies

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

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

@cindex _SCRIPTS primary, defined
@cindex SCRIPTS primary, defined
@cindex Primary variable, SCRIPTS

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

Automake does not assume that scripts are derived objects; such objects
must be deleted by hand (@pxref{Clean}).

The @code{automake} program itself is a Perl 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.

@cindex SCRIPTS, installation directories
@cindex Installing scripts

@vindex bin_SCRIPTS
@vindex sbin_SCRIPTS
@vindex libexec_SCRIPTS
@vindex pkgdata_SCRIPTS
@vindex noinst_SCRIPTS

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


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

@cindex _HEADERS primary, defined
@cindex HEADERS primary, defined
@cindex Primary variable, HEADERS

@vindex noinst_HEADERS

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.

@cindex HEADERS, installation directories
@cindex Installing headers

@vindex include_HEADERS
@vindex oldinclude_HEADERS
@vindex pkginclude_HEADERS

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


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

@cindex _DATA primary, defined
@cindex DATA primary, defined
@cindex Primary variable, DATA

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

@vindex data_DATA
@vindex sysconf_DATA
@vindex sharedstate_DATA
@vindex localstate_DATA
@vindex pkgdata_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 @emph{not} included in a distribution.

Here is how 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

@cindex BUILT_SOURCES, defined

Occasionally a file which would otherwise be called @samp{source}
(e.g. 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 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
surprising 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
* Java::                        Java
@end menu


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

@cindex _LISP primary, defined
@cindex LISP primary, defined
@cindex Primary variable, LISP

@vindex LISP
@vindex lisp_LISP
@vindex noinst_LISP

Automake provides some support for Emacs Lisp.  The @samp{LISP} primary
is used to hold a list of @file{.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 ELCFILES

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 @code{ELCFILES} to be empty.
Byte-compiled Emacs Lisp files are not portable among all versions of
Emacs, so it makes sense to turn this off if you expect sites to have
more than one version of Emacs installed.  Furthermore, many packages
don't actually benefit from byte-compilation.  Still, we recommend that
you leave it enabled by default.  It is probably better for sites with
strange setups to cope for themselves than to make the installation less
nice for everybody else.


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

@cindex GNU Gettext support
@cindex Gettext support
@cindex Support for GNU 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
insures that these directories exist and are mentioned in
@code{SUBDIRS}.

Furthermore, Automake checks that the definition of @code{ALL_LINGUAS}
in @file{configure.in} corresponds to all the valid @file{.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, Java, Guile, Other GNU Tools
@section Libtool

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


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

@cindex _JAVA primary, defined
@cindex JAVA primary, defined
@cindex Primary variable, JAVA

Automake provides some minimal support for Java compilation with the
@samp{JAVA} primary.

Any @file{.java} files listed in a @samp{_JAVA} variable will be
compiled with @code{JAVAC} at build time.  By default, @file{.class}
files are not included in the distribution.

@cindex JAVA restrictions
@cindex Restrictions for JAVA

Currently Automake enforces the restriction that only one @samp{_JAVA}
primary can be used in a given @file{Makefile.am}.  The reason for this
restriction is that, in general, it isn't possible to know which
@file{.class} files were generated from which @file{.java} files -- so
it would be impossible to know which files to install where.


@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

@cindex _TEXINFOS primary, defined
@cindex TEXINFOS primary, defined
@cindex Primary variable, TEXINFOS

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 @file{.texi} or
@file{.texinfo} extension.
@vindex TEXINFOS
@vindex info_TEXINFOS

@cindex Texinfo macro, VERSION
@cindex Texinfo macro, UPDATED
@cindex Texinfo macro, EDITION

@cindex VERSION Texinfo macro
@cindex UPDATED Texinfo macro
@cindex EDITION Texinfo macro

@cindex mdate-sh

If the @file{.texi} file @code{@@include}s @file{version.texi}, then
that file will be automatically generated.  The file @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 and automatically included when @code{automake} is invoked
with the @code{--add-missing} option.

Sometimes an info file actually depends on more than one @file{.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 @code{@var{texi}_TEXINFOS} variable.  Here is how GNU Hello does it:
@vindex TEXINFOS
@vindex _TEXINFOS

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

@cindex texinfo.tex

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} (@pxref{Input, , Finding
`configure' Input, autoconf, The Autoconf Manual}), then
@file{texinfo.tex} is looked for there.  Automake supplies
@file{texinfo.tex} if @samp{--add-missing} is given.

@vindex TEXINFO_TEX

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

@opindex no-texinfo.tex

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.

@cindex Target, install-info
@cindex Target, noinstall-info
@cindex install-info target
@cindex noinstall-info target

@opindex no-installinfo
@trindex install-info

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

@cindex _MANS primary, defined
@cindex MANS primary, defined
@cindex Primary variable, MANS

A package can also include man pages (but 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.
They are not automatically included in the distribution.
@vindex MANS
@vindex man_MANS

@cindex Target, install-man
@cindex Target, noinstall-man
@cindex install-man target
@cindex noinstall-man target

@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
EXTRA_DIST = $(man_MANS)
@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.  For the same
reason, they are not automatically included in the distribution.


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

@cindex Installation support
@cindex make install support

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, an
@code{installdirs} target, and an @code{install-strip} target.
@trindex uninstall
@trindex installdirs
@trindex install-strip

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} (e.g. @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} (e.g. @samp{bin_PROGRAMS}) are installed by
@samp{install-exec}.

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

@vindex DESTDIR
Automake generates support for the @samp{DESTDIR} variable in all
install rules.  @samp{DESTDIR} is used during the @samp{make install}
step to relocate install objects into a staging area.  Each object and
path is prefixed with the value of @samp{DESTDIR} before being copied
into the install area.  Here is an example of typical DESTDIR usage:

@example
make DESTDIR=/tmp/staging install
@end example

This places install objects in a directory tree built under
@file{/tmp/staging}.  If @file{/gnu/bin/foo} and
@file{/gnu/share/aclocal/foo.m4} are to be installed, the above command
would install @file{/tmp/staging/gnu/bin/foo} and
@file{/tmp/staging/gnu/share/aclocal/foo.m4}.

This feature is commonly used to build install images and packages.  For
more information, see @ref{Makefile Conventions, , , standards, The GNU
Coding Standards}.


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

@cindex make clean support

The GNU Makefile Standards specify a number of different clean rules.
@c FIXME xref
Generally the files that can be cleaned are determined automatically by
Automake.  Of course, Automake also recognizes some variables that can
be defined to specify additional files to clean.  These variables are
@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

@cindex make dist
@cindex make distcheck

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
You can use the @code{make} variable @samp{GZIP_ENV} to control how gzip
is run.  The default setting is @samp{--best}.

For the most part, the files to distribute are automatically found by
Automake: all source files are automatically included in a distribution,
as are all @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}
(i.e. 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.  You can mention files from
subdirectories in @code{EXTRA_DIST}.  You can also mention a directory
there; in this case the entire directory will be recursively copied into
the distribution.
@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

@trindex dist-hook

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 $(srcdir)/random/a1 $(srcdir)/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

@cindex Test suites
@cindex make check

Automake supports two forms of test suites.

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 @code{srcdir} and @file{.}.  Programs needing data files should look
for them in @code{srcdir} (which is both an environment variable and a
make variable) so they work when building in a separate directory
(@pxref{Build Directories, , Build Directories , autoconf, The Autoconf
Manual}), and in particular for the @code{distcheck} target
(@pxref{Dist}).

@cindex Exit status 77, special interpretation

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 (e.g.
@samp{$(SHELL) -x}); this can be useful for debugging the tests.
@vindex TESTS
@vindex TESTS_ENVIRONMENT

If @uref{ftp://prep.ai.mit.edu/pub/gnu/dejagnu-1.3.tar.gz,
@samp{dejagnu}} appears in @code{AUTOMAKE_OPTIONS}, then 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}
@item @code{cygnus}
@cindex Option, gnits
@cindex Option, gnu
@cindex Option, foreign
@cindex Option, cygnus

Set the strictness as appropriate.  The @code{gnits} option also implies
@code{readme-alpha} and @code{check-news}.

@item @code{ansi2knr}
@itemx @code{path/ansi2knr}
@cindex Option, ansi2knr
Turn on automatic de-ANSI-fication.  @xref{ANSI}.  If preceded 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{check-news}
@cindex Option, check-news
Cause @code{make dist} to fail unless the current version number appears
in the first few lines of the @file{NEWS} file.

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

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

@item @code{readme-alpha}
@cindex Option, readme-alpha
If this release is an alpha release, and the file @file{README-alpha}
exists, then it will be added to the distribution.  If this option is
given, version numbers are expected to follow one of two forms.  The
first form is @samp{@var{MAJOR}.@var{MINOR}.@var{ALPHA}}, where each
element is a number; the final period and number should be left off for
non-alpha releases.  The second form is
@samp{@var{MAJOR}.@var{MINOR}@var{ALPHA}}, where @var{ALPHA} is a
letter; it should be omitted for non-alpha releases.

@item @var{version}
@cindex Option, version
A version number (e.g. @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, Include, 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}

@cindex TAGS support

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

If any C, C++ or Fortran 77 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

@cindex Adding new SUFFIXES
@cindex SUFFIXES, adding

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 Include, Conditionals, Miscellaneous, Top
@chapter Include

@cmindex include
To include another file (perhaps for common rules),
the following syntax is supported:

include ($(srcdir)|$(top_srcdir))/filename

Using files in the current directory:
@example
include $(srcdir)/Makefile.extra
@end example

@example
include Makefile.generated
@end example

Using a file in the top level directory:
@example
include $(top_srcdir)/filename
@end example


@node Conditionals, Gnits, Include, Top
@chapter Conditionals

@cindex 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 (@pxref{Macros}).
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 @code{if} statement.  The condition is
evaluated when @code{configure} is run.

@cindex --enable-debug, example
@cindex Example conditional --enable-debug
@cindex Conditional example,  --enable-debug

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}:

@cmindex if
@cmindex endif
@cmindex else

@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 @code{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}

@cindex --gnu, required files
@cindex --gnu, complete description

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}.

@cindex --gnits, complete description

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
@cindex README-alpha
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 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}

@cindex Cygnus strictness

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 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}.  Automake will ignore these additions.

@cindex -local targets
@cindex local targets

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

@trindex  all-local
@trindex  info-local
@trindex  dvi-local
@trindex  check-local
@trindex  install-data-local
@trindex  install-exec-local
@trindex  uninstall-local
@trindex  mostlyclean-local
@trindex  clean-local
@trindex  distclean-local

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

@cindex -hook targets
@cindex hook targets

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, Macro and Variable Index, Distributing, Top
@chapter Some ideas for the future

@cindex Future directions

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.

@cindex Guile rewrite

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


@page
@node Macro and Variable Index, General Index, Future, Top
@unnumbered Macro and Variable Index

@printindex vr


@page
@node General Index,  , Macro and Variable Index, Top
@unnumbered General Index

@printindex cp


@page
@contents
@bye