@comment This file is included by both standards.texi and make.texinfo.

@comment It was broken out of standards.texi on 1/6/93 by roland.

@node Makefile Conventions

@chapter Makefile Conventions

@comment standards.texi does not print an index, but make.texinfo does.

@cindex makefile, conventions for

@cindex conventions for makefiles

@cindex standards for makefiles

This

@ifinfo

node

@end ifinfo

@iftex

@ifset CODESTD

section

@end ifset

@ifclear CODESTD

chapter

@end ifclear

@end iftex

describes conventions for writing the Makefiles for GNU programs.

@menu

* Makefile Basics::		General Conventions for Makefiles

* Utilities in Makefiles::	Utilities in Makefiles

* Command Variables::		Variables for Specifying Commands

* Directory Variables::		Variables for Installation Directories

* Standard Targets::		Standard Targets for Users

* Install Command Categories::  Three categories of commands in the `install'

                                  rule: normal, pre-install and post-install.

@end menu

@node Makefile Basics

@section General Conventions for Makefiles

Every Makefile should contain this line:

@example

SHELL = /bin/sh

@end example

@noindent

to avoid trouble on systems where the @code{SHELL} variable might be

inherited from the environment.  (This is never a problem with GNU

@code{make}.)

Different @code{make} programs have incompatible suffix lists and

implicit rules, and this sometimes creates confusion or misbehavior.  So

it is a good idea to set the suffix list explicitly using only the

suffixes you need in the particular Makefile, like this:

@example

.SUFFIXES:

.SUFFIXES: .c .o

@end example

@noindent

The first line clears out the suffix list, the second introduces all

suffixes which may be subject to implicit rules in this Makefile.

Don't assume that @file{.} is in the path for command execution.  When

you need to run programs that are a part of your package during the

make, please make sure that it uses @file{./} if the program is built as

part of the make or @file{$(srcdir)/} if the file is an unchanging part

of the source code.  Without one of these prefixes, the current search

path is used.

The distinction between @file{./} (the @dfn{build directory}) and

@file{$(srcdir)/} (the @dfn{source directory}) is important because

users can build in a separate directory using the @samp{--srcdir} option

to @file{configure}.  A rule of the form:

@smallexample

foo.1 : foo.man sedscript

        sed -e sedscript foo.man > foo.1

@end smallexample

@noindent

will fail when the build directory is not the source directory, because

@file{foo.man} and @file{sedscript} are in the the source directory.

When using GNU @code{make}, relying on @samp{VPATH} to find the source

file will work in the case where there is a single dependency file,

since the @code{make} automatic variable @samp{$<} will represent the

source file wherever it is.  (Many versions of @code{make} set @samp{$<}

only in implicit rules.)  A Makefile target like

@smallexample

foo.o : bar.c

        $(CC) -I. -I$(srcdir) $(CFLAGS) -c bar.c -o foo.o

@end smallexample

@noindent

should instead be written as

@smallexample

foo.o : bar.c

        $(CC) -I. -I$(srcdir) $(CFLAGS) -c $< -o $@@

@end smallexample

@noindent

in order to allow @samp{VPATH} to work correctly.  When the target has

multiple dependencies, using an explicit @samp{$(srcdir)} is the easiest

way to make the rule work well.  For example, the target above for

@file{foo.1} is best written as:

@smallexample

foo.1 : foo.man sedscript

        sed -e $(srcdir)/sedscript $(srcdir)/foo.man > $@@

@end smallexample

GNU distributions usually contain some files which are not source

files---for example, Info files, and the output from Autoconf, Automake,

Bison or Flex.  Since these files normally appear in the source

directory, they should always appear in the source directory, not in the

build directory.  So Makefile rules to update them should put the

updated files in the source directory.

However, if a file does not appear in the distribution, then the

Makefile should not put it in the source directory, because building a

program in ordinary circumstances should not modify the source directory

in any way.

Try to make the build and installation targets, at least (and all their

subtargets) work correctly with a parallel @code{make}.

@node Utilities in Makefiles

@section Utilities in Makefiles

Write the Makefile commands (and any shell scripts, such as

@code{configure}) to run in @code{sh}, not in @code{csh}.  Don't use any

special features of @code{ksh} or @code{bash}.

The @code{configure} script and the Makefile rules for building and

installation should not use any utilities directly except these:

@c dd find

@c gunzip gzip md5sum

@c mkfifo mknod tee uname 

@example

cat cmp cp diff echo egrep expr false grep install-info

ln ls mkdir mv pwd rm rmdir sed sleep sort tar test touch true

@end example

The compression program @code{gzip} can be used in the @code{dist} rule.

Stick to the generally supported options for these programs.  For

example, don't use @samp{mkdir -p}, convenient as it may be, because

most systems don't support it.

It is a good idea to avoid creating symbolic links in makefiles, since a

few systems don't support them.

The Makefile rules for building and installation can also use compilers

and related programs, but should do so via @code{make} variables so that the

user can substitute alternatives.  Here are some of the programs we

mean:

@example

ar bison cc flex install ld ldconfig lex

make makeinfo ranlib texi2dvi yacc

@end example

Use the following @code{make} variables to run those programs:

@example

$(AR) $(BISON) $(CC) $(FLEX) $(INSTALL) $(LD) $(LDCONFIG) $(LEX)

$(MAKE) $(MAKEINFO) $(RANLIB) $(TEXI2DVI) $(YACC)

@end example

When you use @code{ranlib} or @code{ldconfig}, you should make sure

nothing bad happens if the system does not have the program in question.

Arrange to ignore an error from that command, and print a message before

the command to tell the user that failure of this command does not mean

a problem.  (The Autoconf @samp{AC_PROG_RANLIB} macro can help with

this.)

If you use symbolic links, you should implement a fallback for systems

that don't have symbolic links.

Additional utilities that can be used via Make variables are:

@example

chgrp chmod chown mknod

@end example

It is ok to use other utilities in Makefile portions (or scripts)

intended only for particular systems where you know those utilities

exist.

@node Command Variables

@section Variables for Specifying Commands

Makefiles should provide variables for overriding certain commands, options,

and so on.

In particular, you should run most utility programs via variables.

Thus, if you use Bison, have a variable named @code{BISON} whose default

value is set with @samp{BISON = bison}, and refer to it with

@code{$(BISON)} whenever you need to use Bison.

File management utilities such as @code{ln}, @code{rm}, @code{mv}, and

so on, need not be referred to through variables in this way, since users

don't need to replace them with other programs.

Each program-name variable should come with an options variable that is

used to supply options to the program.  Append @samp{FLAGS} to the

program-name variable name to get the options variable name---for

example, @code{BISONFLAGS}.  (The names @code{CFLAGS} for the C

compiler, @code{YFLAGS} for yacc, and @code{LFLAGS} for lex, are

exceptions to this rule, but we keep them because they are standard.)

Use @code{CPPFLAGS} in any compilation command that runs the

preprocessor, and use @code{LDFLAGS} in any compilation command that

does linking as well as in any direct use of @code{ld}.

If there are C compiler options that @emph{must} be used for proper

compilation of certain files, do not include them in @code{CFLAGS}.

Users expect to be able to specify @code{CFLAGS} freely themselves.

Instead, arrange to pass the necessary options to the C compiler

independently of @code{CFLAGS}, by writing them explicitly in the

compilation commands or by defining an implicit rule, like this:

@smallexample

CFLAGS = -g

ALL_CFLAGS = -I. $(CFLAGS)

.c.o:

        $(CC) -c $(CPPFLAGS) $(ALL_CFLAGS) $<

@end smallexample

Do include the @samp{-g} option in @code{CFLAGS}, because that is not

@emph{required} for proper compilation.  You can consider it a default

that is only recommended.  If the package is set up so that it is

compiled with GCC by default, then you might as well include @samp{-O}

in the default value of @code{CFLAGS} as well.

Put @code{CFLAGS} last in the compilation command, after other variables

containing compiler options, so the user can use @code{CFLAGS} to

override the others.

@code{CFLAGS} should be used in every invocation of the C compiler,

both those which do compilation and those which do linking.

Every Makefile should define the variable @code{INSTALL}, which is the

basic command for installing a file into the system.

Every Makefile should also define the variables @code{INSTALL_PROGRAM}

and @code{INSTALL_DATA}.  (The default for each of these should be

@code{$(INSTALL)}.)  Then it should use those variables as the commands

for actual installation, for executables and nonexecutables

respectively.  Use these variables as follows:

@example

$(INSTALL_PROGRAM) foo $(bindir)/foo

$(INSTALL_DATA) libfoo.a $(libdir)/libfoo.a

@end example

@noindent

Always use a file name, not a directory name, as the second argument of

the installation commands.  Use a separate command for each file to be

installed.

@node Directory Variables

@section Variables for Installation Directories

Installation directories should always be named by variables, so it is

easy to install in a nonstandard place.  The standard names for these

variables are described below.  They are based on a standard filesystem

layout; variants of it are used in SVR4, 4.4BSD, Linux, Ultrix v4, and

other modern operating systems.

These two variables set the root for the installation.  All the other

installation directories should be subdirectories of one of these two,

and nothing should be directly installed into these two directories.

@table @samp

@item prefix

A prefix used in constructing the default values of the variables listed

below.  The default value of @code{prefix} should be @file{/usr/local}.

When building the complete GNU system, the prefix will be empty and

@file{/usr} will be a symbolic link to @file{/}.

(If you are using Autoconf, write it as @samp{@@prefix@@}.)

@item exec_prefix

A prefix used in constructing the default values of some of the

variables listed below.  The default value of @code{exec_prefix} should

be @code{$(prefix)}.

(If you are using Autoconf, write it as @samp{@@exec_prefix@@}.)

Generally, @code{$(exec_prefix)} is used for directories that contain

machine-specific files (such as executables and subroutine libraries),

while @code{$(prefix)} is used directly for other directories.

@end table

Executable programs are installed in one of the following directories.

@table @samp

@item bindir

The directory for installing executable programs that users can run.

This should normally be @file{/usr/local/bin}, but write it as

@file{$(exec_prefix)/bin}.

(If you are using Autoconf, write it as @samp{@@bindir@@}.)

@item sbindir

The directory for installing executable programs that can be run from

the shell, but are only generally useful to system administrators.  This

should normally be @file{/usr/local/sbin}, but write it as

@file{$(exec_prefix)/sbin}.

(If you are using Autoconf, write it as @samp{@@sbindir@@}.)

@item libexecdir

@comment This paragraph adjusted to avoid overfull hbox --roland 5jul94

The directory for installing executable programs to be run by other

programs rather than by users.  This directory should normally be

@file{/usr/local/libexec}, but write it as @file{$(exec_prefix)/libexec}.

(If you are using Autoconf, write it as @samp{@@libexecdir@@}.)

@end table

Data files used by the program during its execution are divided into

categories in two ways.

@itemize @bullet

@item

Some files are normally modified by programs; others are never normally

modified (though users may edit some of these).

@item

Some files are architecture-independent and can be shared by all

machines at a site; some are architecture-dependent and can be shared

only by machines of the same kind and operating system; others may never

be shared between two machines.

@end itemize

This makes for six different possibilities.  However, we want to

discourage the use of architecture-dependent files, aside from object

files and libraries.  It is much cleaner to make other data files

architecture-independent, and it is generally not hard.

Therefore, here are the variables Makefiles should use to specify

directories:

@table @samp

@item datadir

The directory for installing read-only architecture independent data

files.  This should normally be @file{/usr/local/share}, but write it as

@file{$(prefix)/share}.

(If you are using Autoconf, write it as @samp{@@datadir@@}.)

As a special exception, see @file{$(infodir)}

and @file{$(includedir)} below.

@item sysconfdir

The directory for installing read-only data files that pertain to a

single machine--that is to say, files for configuring a host.  Mailer

and network configuration files, @file{/etc/passwd}, and so forth belong

here.  All the files in this directory should be ordinary ASCII text

files.  This directory should normally be @file{/usr/local/etc}, but

write it as @file{$(prefix)/etc}.

(If you are using Autoconf, write it as @samp{@@sysconfdir@@}.)

Do not install executables here in this directory (they probably belong

in @file{$(libexecdir)} or @file{$(sbindir)}).  Also do not install

files that are modified in the normal course of their use (programs

whose purpose is to change the configuration of the system excluded).

Those probably belong in @file{$(localstatedir)}.

@item sharedstatedir

The directory for installing architecture-independent data files which

the programs modify while they run.  This should normally be

@file{/usr/local/com}, but write it as @file{$(prefix)/com}.

(If you are using Autoconf, write it as @samp{@@sharedstatedir@@}.)

@item localstatedir

The directory for installing data files which the programs modify while

they run, and that pertain to one specific machine.  Users should never

need to modify files in this directory to configure the package's

operation; put such configuration information in separate files that go

in @file{$(datadir)} or @file{$(sysconfdir)}.  @file{$(localstatedir)}

should normally be @file{/usr/local/var}, but write it as

@file{$(prefix)/var}.

(If you are using Autoconf, write it as @samp{@@localstatedir@@}.)

@item libdir

The directory for object files and libraries of object code.  Do not

install executables here, they probably ought to go in @file{$(libexecdir)}

instead.  The value of @code{libdir} should normally be

@file{/usr/local/lib}, but write it as @file{$(exec_prefix)/lib}.

(If you are using Autoconf, write it as @samp{@@libdir@@}.)

@item infodir

The directory for installing the Info files for this package.  By

default, it should be @file{/usr/local/info}, but it should be written

as @file{$(prefix)/info}.

(If you are using Autoconf, write it as @samp{@@infodir@@}.)

@item lispdir

The directory for installing any Emacs Lisp files in this package.  By

default, it should be @file{/usr/local/share/emacs/site-lisp}, but it

should be written as @file{$(prefix)/share/emacs/site-lisp}.

If you are using Autoconf, write the default as @samp{@@lispdir@@}.

In order to make @samp{@@lispdir@@} work, you need the following lines

in your @file{configure.in} file:

@example

lispdir='$@{datadir@}/emacs/site-lisp'

AC_SUBST(lispdir)

@end example

@item includedir

@c rewritten to avoid overfull hbox --roland

The directory for installing header files to be included by user

programs with the C @samp{#include} preprocessor directive.  This

should normally be @file{/usr/local/include}, but write it as

@file{$(prefix)/include}.

(If you are using Autoconf, write it as @samp{@@includedir@@}.)

Most compilers other than GCC do not look for header files in directory

@file{/usr/local/include}.  So installing the header files this way is

only useful with GCC.  Sometimes this is not a problem because some

libraries are only really intended to work with GCC.  But some libraries

are intended to work with other compilers.  They should install their

header files in two places, one specified by @code{includedir} and one

specified by @code{oldincludedir}.

@item oldincludedir

The directory for installing @samp{#include} header files for use with

compilers other than GCC.  This should normally be @file{/usr/include}.

(If you are using Autoconf, you can write it as @samp{@@oldincludedir@@}.)

The Makefile commands should check whether the value of

@code{oldincludedir} is empty.  If it is, they should not try to use

it; they should cancel the second installation of the header files.

A package should not replace an existing header in this directory unless

the header came from the same package.  Thus, if your Foo package

provides a header file @file{foo.h}, then it should install the header

file in the @code{oldincludedir} directory if either (1) there is no

@file{foo.h} there or (2) the @file{foo.h} that exists came from the Foo

package.

To tell whether @file{foo.h} came from the Foo package, put a magic

string in the file---part of a comment---and @code{grep} for that string.

@end table

Unix-style man pages are installed in one of the following:

@table @samp

@item mandir

The top-level directory for installing the man pages (if any) for this

package.  It will normally be @file{/usr/local/man}, but you should

write it as @file{$(prefix)/man}.

(If you are using Autoconf, write it as @samp{@@mandir@@}.)

@item man1dir

The directory for installing section 1 man pages.  Write it as

@file{$(mandir)/man1}.

@item man2dir

The directory for installing section 2 man pages.  Write it as

@file{$(mandir)/man2}

@item @dots{}

@strong{Don't make the primary documentation for any GNU software be a

man page.  Write a manual in Texinfo instead.  Man pages are just for

the sake of people running GNU software on Unix, which is a secondary

application only.}

@item manext

The file name extension for the installed man page.  This should contain

a period followed by the appropriate digit; it should normally be @samp{.1}.

@item man1ext

The file name extension for installed section 1 man pages.

@item man2ext

The file name extension for installed section 2 man pages.

@item @dots{}

Use these names instead of @samp{manext} if the package needs to install man

pages in more than one section of the manual.

@end table

And finally, you should set the following variable:

@table @samp

@item srcdir

The directory for the sources being compiled.  The value of this

variable is normally inserted by the @code{configure} shell script.

(If you are using Autconf, use @samp{srcdir = @@srcdir@@}.)

@end table

For example:

@smallexample

@c I have changed some of the comments here slightly to fix an overfull

@c hbox, so the make manual can format correctly. --roland

# Common prefix for installation directories.

# NOTE: This directory must exist when you start the install.

prefix = /usr/local

exec_prefix = $(prefix)

# Where to put the executable for the command `gcc'.

bindir = $(exec_prefix)/bin

# Where to put the directories used by the compiler.

libexecdir = $(exec_prefix)/libexec

# Where to put the Info files.

infodir = $(prefix)/info

@end smallexample

If your program installs a large number of files into one of the

standard user-specified directories, it might be useful to group them

into a subdirectory particular to that program.  If you do this, you

should write the @code{install} rule to create these subdirectories.

Do not expect the user to include the subdirectory name in the value of

any of the variables listed above.  The idea of having a uniform set of

variable names for installation directories is to enable the user to

specify the exact same values for several different GNU packages.  In

order for this to be useful, all the packages must be designed so that

they will work sensibly when the user does so.

@node Standard Targets

@section Standard Targets for Users

All GNU programs should have the following targets in their Makefiles:

@table @samp

@item all

Compile the entire program.  This should be the default target.  This

target need not rebuild any documentation files; Info files should

normally be included in the distribution, and DVI files should be made

only when explicitly asked for.

By default, the Make rules should compile and link with @samp{-g}, so

that executable programs have debugging symbols.  Users who don't mind

being helpless can strip the executables later if they wish.

@item install

Compile the program and copy the executables, libraries, and so on to

the file names where they should reside for actual use.  If there is a

simple test to verify that a program is properly installed, this target

should run that test.

Do not strip executables when installing them.  Devil-may-care users can

use the @code{install-strip} target to do that.

If possible, write the @code{install} target rule so that it does not

modify anything in the directory where the program was built, provided

@samp{make all} has just been done.  This is convenient for building the

program under one user name and installing it under another.

The commands should create all the directories in which files are to be

installed, if they don't already exist.  This includes the directories

specified as the values of the variables @code{prefix} and

@code{exec_prefix}, as well as all subdirectories that are needed.

One way to do this is by means of an @code{installdirs} target

as described below.

Use @samp{-} before any command for installing a man page, so that

@code{make} will ignore any errors.  This is in case there are systems

that don't have the Unix man page documentation system installed.

The way to install Info files is to copy them into @file{$(infodir)}

with @code{$(INSTALL_DATA)} (@pxref{Command Variables}), and then run

the @code{install-info} program if it is present.  @code{install-info}

is a program that edits the Info @file{dir} file to add or update the

menu entry for the given Info file; it is part of the Texinfo package.

Here is a sample rule to install an Info file:

@comment This example has been carefully formatted for the Make manual.

@comment Please do not reformat it without talking to roland@gnu.ai.mit.edu.

@smallexample

$(infodir)/foo.info: foo.info

        $(POST_INSTALL)

# There may be a newer info file in . than in srcdir.

        -if test -f foo.info; then d=.; \

         else d=$(srcdir); fi; \

        $(INSTALL_DATA) $$d/foo.info $@@; \

# Run install-info only if it exists.

# Use `if' instead of just prepending `-' to the

# line so we notice real errors from install-info.

# We use `$(SHELL) -c' because some shells do not

# fail gracefully when there is an unknown command.

        if $(SHELL) -c 'install-info --version' \

           >/dev/null 2>&1; then \

          install-info --dir-file=$(infodir)/dir \

                       $(infodir)/foo.info; \

        else true; fi

@end smallexample

When writing the @code{install} target, you must classify all the

commands into three categories: normal ones, @dfn{pre-installation}

commands and @dfn{post-installation} commands.  @xref{Install Command

Categories}.

@item uninstall

Delete all the installed files---the copies that the @samp{install}

target creates.

This rule should not modify the directories where compilation is done,

only the directories where files are installed.

The uninstallation commands are divided into three categories, just like

the installation commands.  @xref{Install Command Categories}.

@item install-strip

Like @code{install}, but strip the executable files while installing

them.  In many cases, the definition of this target can be very simple:

@smallexample

install-strip:

        $(MAKE) INSTALL_PROGRAM='$(INSTALL_PROGRAM) -s' \

                install

@end smallexample

Normally we do not recommend stripping an executable unless you are sure

the program has no bugs.  However, it can be reasonable to install a

stripped executable for actual execution while saving the unstripped

executable elsewhere in case there is a bug.

@comment The gratuitous blank line here is to make the table look better

@comment in the printed Make manual.  Please leave it in.

@item clean

Delete all files from the current directory that are normally created by

building the program.  Don't delete the files that record the

configuration.  Also preserve files that could be made by building, but

normally aren't because the distribution comes with them.

Delete @file{.dvi} files here if they are not part of the distribution.

@item distclean

Delete all files from the current directory that are created by

configuring or building the program.  If you have unpacked the source

and built the program without creating any other files, @samp{make

distclean} should leave only the files that were in the distribution.

@item mostlyclean

Like @samp{clean}, but may refrain from deleting a few files that people

normally don't want to recompile.  For example, the @samp{mostlyclean}

target for GCC does not delete @file{libgcc.a}, because recompiling it

is rarely necessary and takes a lot of time.

@item maintainer-clean

Delete almost everything from the current directory that can be

reconstructed with this Makefile.  This typically includes everything

deleted by @code{distclean}, plus more: C source files produced by

Bison, tags tables, Info files, and so on.

The reason we say ``almost everything'' is that running the command

@samp{make maintainer-clean} should not delete @file{configure} even if

@file{configure} can be remade using a rule in the Makefile.  More generally,

@samp{make maintainer-clean} should not delete anything that needs to

exist in order to run @file{configure} and then begin to build the

program.  This is the only exception; @code{maintainer-clean} should

delete everything else that can be rebuilt.

The @samp{maintainer-clean} target is intended to be used by a maintainer of

the package, not by ordinary users.  You may need special tools to

reconstruct some of the files that @samp{make maintainer-clean} deletes.

Since these files are normally included in the distribution, we don't

take care to make them easy to reconstruct.  If you find you need to

unpack the full distribution again, don't blame us.

To help make users aware of this, the commands for the special

@code{maintainer-clean} target should start with these two:

@smallexample

@@echo 'This command is intended for maintainers to use; it'

@@echo 'deletes files that may need special tools to rebuild.'

@end smallexample

@item TAGS

Update a tags table for this program.

@c ADR: how?

@item info

Generate any Info files needed.  The best way to write the rules is as

follows:

@smallexample

info: foo.info

foo.info: foo.texi chap1.texi chap2.texi

        $(MAKEINFO) $(srcdir)/foo.texi

@end smallexample

@noindent

You must define the variable @code{MAKEINFO} in the Makefile.  It should

run the @code{makeinfo} program, which is part of the Texinfo

distribution.

Normally a GNU distribution comes with Info files, and that means the

Info files are present in the source directory.  Therefore, the Make

rule for an info file should update it in the source directory.  When

users build the package, ordinarily Make will not update the Info files

because they will already be up to date.

@item dvi

Generate DVI files for all Texinfo documentation.

For example:

@smallexample

dvi: foo.dvi

foo.dvi: foo.texi chap1.texi chap2.texi

        $(TEXI2DVI) $(srcdir)/foo.texi

@end smallexample

@noindent

You must define the variable @code{TEXI2DVI} in the Makefile.  It should

run the program @code{texi2dvi}, which is part of the Texinfo

distribution.@footnote{@code{texi2dvi} uses @TeX{} to do the real work

of formatting. @TeX{} is not distributed with Texinfo.}  Alternatively,

write just the dependencies, and allow GNU @code{make} to provide the command.

@item dist

Create a distribution tar file for this program.  The tar file should be

set up so that the file names in the tar file start with a subdirectory

name which is the name of the package it is a distribution for.  This

name can include the version number.

For example, the distribution tar file of GCC version 1.40 unpacks into

a subdirectory named @file{gcc-1.40}.

The easiest way to do this is to create a subdirectory appropriately

named, use @code{ln} or @code{cp} to install the proper files in it, and

then @code{tar} that subdirectory.

Compress the tar file file with @code{gzip}.  For example, the actual

distribution file for GCC version 1.40 is called @file{gcc-1.40.tar.gz}.

The @code{dist} target should explicitly depend on all non-source files

that are in the distribution, to make sure they are up to date in the

distribution.

@ifset CODESTD

@xref{Releases, , Making Releases}.

@end ifset

@ifclear CODESTD

@xref{Releases, , Making Releases, standards, GNU Coding Standards}.

@end ifclear

@item check

Perform self-tests (if any).  The user must build the program before

running the tests, but need not install the program; you should write

the self-tests so that they work when the program is built but not

installed.

@end table

The following targets are suggested as conventional names, for programs

in which they are useful.

@table @code

@item installcheck

Perform installation tests (if any).  The user must build and install

the program before running the tests.  You should not assume that

@file{$(bindir)} is in the search path.

@item installdirs

It's useful to add a target named @samp{installdirs} to create the

directories where files are installed, and their parent directories.

There is a script called @file{mkinstalldirs} which is convenient for

this; you can find it in the Texinfo package.

@c It's in /gd/gnu/lib/mkinstalldirs.

You can use a rule like this:

@comment This has been carefully formatted to look decent in the Make manual.

@comment Please be sure not to make it extend any further to the right.--roland

@smallexample

# Make sure all installation directories (e.g. $(bindir))

# actually exist by making them if necessary.

installdirs: mkinstalldirs

        $(srcdir)/mkinstalldirs $(bindir) $(datadir) \

                                $(libdir) $(infodir) \

                                $(mandir)

@end smallexample

This rule should not modify the directories where compilation is done.

It should do nothing but create installation directories.

@end table

@node Install Command Categories

@section Install Command Categories

@cindex pre-installation commands

@cindex post-installation commands

When writing the @code{install} target, you must classify all the

commands into three categories: normal ones, @dfn{pre-installation}

commands and @dfn{post-installation} commands.

Normal commands move files into their proper places, and set their

modes.  They may not alter any files except the ones that come entirely

from the package they belong to.

Pre-installation and post-installation commands may alter other files;

in particular, they can edit global configuration files or data bases.

Pre-installation commands are typically executed before the normal

commands, and post-installation commands are typically run after the

normal commands.

The most common use for a post-installation command is to run

@code{install-info}.  This cannot be done with a normal command, since

it alters a file (the Info directory) which does not come entirely and

solely from the package being installed.  It is a post-installation

command because it needs to be done after the normal command which

installs the package's Info files.

Most programs don't need any pre-installation commands, but we have the

feature just in case it is needed.

To classify the commands in the @code{install} rule into these three

categories, insert @dfn{category lines} among them.  A category line

specifies the category for the commands that follow.

A category line consists of a tab and a reference to a special Make

variable, plus an optional comment at the end.  There are three

variables you can use, one for each category; the variable name

specifies the category.  Category lines are no-ops in ordinary execution

because these three Make variables are normally undefined (and you

@emph{should not} define them in the makefile).

Here are the three possible category lines, each with a comment that

explains what it means:

@smallexample

        $(PRE_INSTALL)     # @r{Pre-install commands follow.}

        $(POST_INSTALL)    # @r{Post-install commands follow.}

        $(NORMAL_INSTALL)  # @r{Normal commands follow.}

@end smallexample

If you don't use a category line at the beginning of the @code{install}

rule, all the commands are classified as normal until the first category

line.  If you don't use any category lines, all the commands are

classified as normal.

These are the category lines for @code{uninstall}:

@smallexample

        $(PRE_UNINSTALL)     # @r{Pre-uninstall commands follow.}

        $(POST_UNINSTALL)    # @r{Post-uninstall commands follow.}

        $(NORMAL_UNINSTALL)  # @r{Normal commands follow.}

@end smallexample

Typically, a pre-uninstall command would be used for deleting entries

from the Info directory.

If the @code{install} or @code{uninstall} target has any dependencies

which act as subroutines of installation, then you should start

@emph{each} dependency's commands with a category line, and start the

main target's commands with a category line also.  This way, you can

ensure that each command is placed in the right category regardless of

which of the dependencies actually run.

Pre-installation and post-installation commands should not run any

programs except for these:

@example

[ basename bash cat chgrp chmod chown cmp cp dd diff echo

egrep expand expr false fgrep find getopt grep gunzip gzip

hostname install install-info kill ldconfig ln ls md5sum

mkdir mkfifo mknod mv printenv pwd rm rmdir sed sort tee

test touch true uname xargs yes

@end example

@cindex binary packages

The reason for distinguishing the commands in this way is for the sake

of making binary packages.  Typically a binary package contains all the

executables and other files that need to be installed, and has its own

method of installing them---so it does not need to run the normal

installation commands.  But installing the binary package does need to

execute the pre-installation and post-installation commands.

Programs to build binary packages work by extracting the

pre-installation and post-installation commands.  Here is one way of

extracting the pre-installation commands:

@smallexample

make -n install -o all \

      PRE_INSTALL=pre-install \

      POST_INSTALL=post-install \

      NORMAL_INSTALL=normal-install \