#	@(#)bsd.README	8.2 (Berkeley) 4/2/94
# $FreeBSD: releng/9.2/share/mk/bsd.README 248350 2013-03-15 20:34:10Z brooks $

This is the README file for the "include" files for the FreeBSD
source tree.  The files are installed in /usr/share/mk, and are by
convention, named with the suffix ".mk".  These files store several
build options and should be handled with caution.

Note, this file is not intended to replace reading through the .mk
files for anything tricky.

There are two main types of make include files.  One type is the generally
usable make include files, such as bsd.prog.mk and bsd.lib.mk.  The other is
the internal make include files, such as bsd.files.mk and bsd.man.mk, which
can not/should not be used directly but are used by the other make include
files.  In most cases it is only interesting to include bsd.prog.mk or
bsd.lib.mk.

bsd.cpu.mk		- sets CPU/arch-related variables
bsd.dep.mk		- handle Makefile dependencies
bsd.doc.mk		- building troff system documents
bsd.files.mk		- install of general purpose files
bsd.incs.mk		- install of include files
bsd.info.mk		- building GNU Info hypertext system
bsd.init.mk		- initialization for the make include files
bsd.kmod.mk		- building loadable kernel modules
bsd.lib.mk		- support for building libraries
bsd.libnames.mk		- define library names
bsd.links.mk		- install of links (sym/hard)
bsd.man.mk		- install of manual pages and their links
bsd.nls.mk		- build and install of NLS catalogs
bsd.obj.mk		- creating 'obj' directories and cleaning up
bsd.own.mk		- define common variables
bsd.port.mk		- building ports
bsd.port.post.mk	- building ports
bsd.port.pre.mk		- building ports
bsd.port.subdir.mk	- targets for building subdirectories for ports
bsd.prog.mk		- building programs from source files
bsd.snmpmod.mk		- building modules for the SNMP daemon bsnmpd
bsd.subdir.mk		- targets for building subdirectories
bsd.sys.mk		- common settings used for building FreeBSD sources
sys.mk			- default rules for all makes

This file does not document bsd.port*.mk.  They are documented in ports(7).

See also make(1), mkdep(1), style.Makefile(5) and `PMake - A
Tutorial', located in /usr/share/doc/psd/12.make.

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Random things worth knowing about this document:

If appropriate when documenting the variables the default value is
indicated using square brackets e.g. [gzip].
In some cases the default value depend on other values (e.g. system
architecture).  In these cases the most common value is indicated.

This document contains some simple examples of the usage of the BSD make
include files.  For more examples look at the makefiles in the FreeBSD
source tree.

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RANDOM THINGS WORTH KNOWING:

The files are like C-style #include files, and pretty much behave like
you'd expect.  The syntax is slightly different in that a single '.' is
used instead of the hash mark, i.e. ".include <bsd.prog.mk>".

One difference that will save you lots of debugging time is that inclusion
of the file is normally done at the *end* of the Makefile.  The reason for
this is because .mk files often modify variables and behavior based on the
values of variables set in the Makefile.  To make this work, remember that
the FIRST target found is the target that is used, i.e. if the Makefile has:

	a:
		echo a
	a:
		echo a number two

the command "make a" will echo "a".  To make things confusing, the SECOND
variable assignment is the overriding one, i.e. if the Makefile has:

	a=	foo
	a=	bar

	b:
		echo ${a}

the command "make b" will echo "bar".  This is for compatibility with the
way the V7 make behaved.

It's fairly difficult to make the BSD .mk files work when you're building
multiple programs in a single directory.  It's a lot easier to split up
the programs than to deal with the problem.  Most of the agony comes from
making the "obj" directory stuff work right, not because we switch to a new
version of make.  So, don't get mad at us, figure out a better way to handle
multiple architectures so we can quit using the symbolic link stuff.
(Imake doesn't count.)

The file .depend in the source directory is expected to contain dependencies
for the source files.  This file is read automatically by make after reading
the Makefile.

The variable DESTDIR works as before.  It's not set anywhere but will change
the tree where the file gets installed.

The profiled libraries are no longer built in a different directory than
the regular libraries.  A new suffix, ".po", is used to denote a profiled
object.

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The include file <sys.mk> has the default rules for all makes, in the BSD
environment or otherwise.  You probably don't want to touch this file.

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The include file <bsd.man.mk> handles installing manual pages and their
links.

It has three targets:

	all-man:
		build manual pages.
	maninstall:
		install the manual pages and their links.
	manlint:
		verify the validity of manual pages.

It sets/uses the following variables:

MANDIR		Base path for manual installation.

MANGRP		Manual group.

MANOWN		Manual owner.

MANMODE		Manual mode.

MANSUBDIR	Subdirectory under the manual page section, i.e. "/vax"
		or "/tahoe" for machine specific manual pages.

MAN		The manual pages to be installed (use a .1 - .9 suffix).

MLINKS		List of manual page links (using a .1 - .9 suffix).  The
		linked-to file must come first, the linked file second,
		and there may be multiple pairs.  The files are soft-linked.

The include file <bsd.man.mk> includes a file named "../Makefile.inc" if
it exists.

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The include file <bsd.own.mk> contains the owners, groups, etc. for both
manual pages and binaries.

It has no targets.

It sets/uses the following variables:

BINGRP		Binary group.

BINOWN		Binary owner.

BINMODE		Binary mode.

MANDIR		Base path for manual installation.

MANGRP		Manual group.

MANOWN		Manual owner.

MANMODE		Manual mode.

This file is generally useful when building your own Makefiles so that
they use the same default owners etc. as the rest of the tree.

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The include file <bsd.prog.mk> handles building programs from one or
more source files, along with their manual pages.  It has a limited number
of suffixes, consistent with the current needs of the BSD tree.

It has seven targets:

	all:
		build the program and its manual page
	clean:
		remove the program and any object files.
	cleandir:
		remove all of the files removed by the target clean, as
		well as .depend, tags, and any manual pages.
	depend:
		make the dependencies for the source files, and store
		them in the file .depend.
	install:
		install the program and its manual pages; if the Makefile
		does not itself define the target install, the targets
		beforeinstall and afterinstall may also be used to cause
		actions immediately before and after the install target
		is executed.
	lint:
		run lint on the source files
	tags:
		create a tags file for the source files.

It sets/uses the following variables:

BINGRP		Binary group.

BINOWN		Binary owner.

BINMODE		Binary mode.

CLEANFILES	Additional files to remove and
CLEANDIRS	additional directories to remove during clean and cleandir
		targets.  "rm -f" and "rm -rf" used respectively.

CFLAGS		Flags to the compiler when creating C objects.

FILES		A list of non-executable files.
		The installation is controlled by the FILESNAME, FILESOWN,
		FILESGRP, FILESMODE, FILESDIR variables that can be
		further specialized by FILES<VAR>_<file>.

LDADD		Additional loader objects.  Usually used for libraries.
		For example, to load with the compatibility and utility
		libraries, use:

			LDFILES=-lutil -lcompat

LDFLAGS		Additional loader flags.

LINKS		The list of binary links; should be full pathnames, the
		linked-to file coming first, followed by the linked
		file.  The files are hard-linked.  For example, to link
		/bin/test and /bin/[, use:

			LINKS=	${DESTDIR}/bin/test ${DESTDIR}/bin/[

MAN		Manual pages (should end in .1 - .9).  If no MAN variable
		is defined, "MAN=${PROG}.1" is assumed.

PROG		The name of the program to build.  If not supplied, nothing
		is built.

PROG_CXX	If defined, the name of the program to build.  Also
		causes <bsd.prog.mk> to link the program with the
		standard C++ library.  PROG_CXX overrides the value
		of PROG if PROG is also set.

PROGNAME	The name that the above program will be installed as, if
		different from ${PROG}.

SRCS		List of source files to build the program.  If SRCS is not
		defined, it's assumed to be ${PROG}.c or, if PROG_CXX is
		defined, ${PROG_CXX}.cc.

DPADD		Additional dependencies for the program.  Usually used for
		libraries.  For example, to depend on the compatibility and
		utility libraries use:

			SRCLIB=${LIBCOMPAT} ${LIBUTIL}

		There is a predefined identifier for each (non-profiled,
		non-shared) library and object.  Library file names are
		transformed to identifiers by removing the extension and
		converting to upper case.

		There are no special identifiers for profiled or shared
		libraries or objects.  The identifiers for the standard
		libraries are used in DPADD.  This works correctly iff all
		the libraries are built at the same time.  Unfortunately,
		it causes unnecessary relinks to shared libraries when
		only the static libraries have changed.  Dependencies on
		shared libraries should be only on the library version
		numbers.

STRIP		The flag passed to the install program to cause the binary
		to be stripped.  This is to be used when building your
		own install script so that the entire system can be made
		stripped/not-stripped using a single nob.

SUBDIR		A list of subdirectories that should be built as well.
		Each of the targets will execute the same target in the
		subdirectories.

SCRIPTS		A list of interpreter scripts [file.{sh,csh,pl,awk,...}].
		The installation is controlled by the SCRIPTSNAME, SCRIPTSOWN,
		SCRIPTSGRP, SCRIPTSMODE, SCRIPTSDIR variables that can be
		further specialized by SCRIPTS<VAR>_<script>.

The include file <bsd.prog.mk> includes the file named "../Makefile.inc"
if it exists, as well as the include file <bsd.man.mk>.

Some simple examples:

To build foo from foo.c with a manual page foo.1, use:

	PROG=	foo

	.include <bsd.prog.mk>

To build foo from foo.c with a manual page foo.2, add the line:

	MAN=	foo.2

If foo does not have a manual page at all, add the line:

	NO_MAN=

If foo has multiple source files, add the line:

	SRCS=	a.c b.c c.c d.c

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The include file <bsd.subdir.mk> contains the default targets for building
subdirectories.  It has the same seven targets as <bsd.prog.mk>: all, clean,
cleandir, depend, install, lint, and tags.  For all of the directories
listed in the variable SUBDIRS, the specified directory will be visited
and the target made.  There is also a default target which allows the
command "make subdir" where subdir is any directory listed in the variable
SUBDIRS.

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The include file <bsd.lib.mk> has support for building libraries.  It has
the same seven targets as <bsd.prog.mk>: all, clean, cleandir, depend,
install, lint, and tags.  It has a limited number of suffixes, consistent
with the current needs of the BSD tree.

It sets/uses the following variables:

LIBDIR		Target directory for libraries.

LINTLIBDIR	Target directory for lint libraries.

LIBGRP		Library group.

LIBOWN		Library owner.

LIBMODE		Library mode.

LDADD		Additional loader objects.

MAN		The manual pages to be installed (use a .1 - .9 suffix).

SRCS		List of source files to build the library.  Suffix types
		.s, .c, and .f are supported.  Note, .s files are preferred
		to .c files of the same name.  (This is not the default for
		versions of make.)

SHLIB_LDSCRIPT	Template file to generate shared library linker script.
		Unless used, a simple symlink is created to the real
		shared object.

LIBRARIES_ONLY	Do not build or install files other than the library.

The include file <bsd.lib.mk> includes the file named "../Makefile.inc"
if it exists, as well as the include file <bsd.man.mk>.

It has rules for building profiled objects; profiled libraries are
built by default.

Libraries are ranlib'd before installation.
