bsd.readme

早期freebsd实现

#	@(#)bsd.README	8.2 (Berkeley) 4/2/94

This is the README file for the new make "include" files for the BSD
source tree.  The files are installed in /usr/share/mk, and are, by
convention, named with the suffix ".mk".  Each ".mk" file has a
corresponding ".rd" file which is an explanation of the ".mk" file.

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

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RANDOM THINGS WORTH KNOWING:

The files are simply 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 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 a single target:

	maninstall:
		Install the manual pages and their links.

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.

MAN1 ... MAN8	The manual pages to be installed (use a .0 suffix).

MLINKS		List of manual page links (using a .1 - .8 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.

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.

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, any object files and the files a.out,
		Errs, errs, mklog, and ${PROG}.core.
	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 for the clean and cleandir targets.

COPTS		Additional flags to the compiler when creating C objects.

HIDEGAME	If HIDEGAME is defined, the binary is installed in
		/usr/games/hide, and a symbolic link is created to
		/usr/games/dm.

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/[

MAN1...MAN8	Manual pages (should end in .0).  If no MAN variable is
		defined, "MAN1=${PROG}.0" is assumed.

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

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

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

			SRCLIB=${LIBCOMPAT} ${LIBUTIL}

		The following libraries are predefined for DPADD:

			LIBC		/lib/libc.a
			LIBCOMPAT	/usr/lib/libcompat.a
			LIBCURSES	/usr/lib/libcurses.a
			LIBDBM		/usr/lib/libdbm.a
			LIBDES		/usr/lib/libdes.a
			LIBL		/usr/lib/libl.a
			LIBKDB		/usr/lib/libkdb.a
			LIBKRB		/usr/lib/libkrb.a
			LIBM		/usr/lib/libm.a
			LIBMP		/usr/lib/libmp.a
			LIBPC		/usr/lib/libpc.a
			LIBPLOT		/usr/lib/libplot.a
			LIBRPC		/usr/lib/sunrpc.a
			LIBTERM		/usr/lib/libterm.a
			LIBUTIL		/usr/lib/libutil.a

SHAREDSTRINGS	If defined, a new .c.o rule is used that results in shared
		strings, using xstr(1).

STRIP		The flag passed to the install program to cause the binary
		to be stripped.

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

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:

	MAN2=	foo.0

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

	NOMAN=	noman

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.

MAN1 ... MAN8	The manual pages to be installed (use a .0 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.)

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.