STYLE.MAKEFILE(5) FreeBSD File Formats Manual STYLE.MAKEFILE(5)
NAME
style.Makefile - FreeBSD Makefile style guide
DESCRIPTION
This file specifies the preferred style for makefiles in the FreeBSD
source tree.
o .PATH: comes first if needed, and is spelled ".PATH: ", with a single
ASCII space after a colon. Do not use the VPATH variable.
o Special variables (i.e., LIB, SRCS, MLINKS, etc.) are listed in order
of "product", then building and installing a binary. Special
variables may also be listed in "build" order: i.e., ones for the
primary program (or library) first. The general "product" order is:
PROG/[SH]LIB/SCRIPTS FILES LINKS MAN MLINKS INCS SRCS WARNS CSTD
CFLAGS DPADD LDADD. The general "build" order is:
PROG/[SH]LIB/SCRIPTS SRCS WARNS CSTD CFLAGS DPADD LDADD INCS FILES
LINKS MAN MLINKS.
o Omit SRCS when using <bsd.prog.mk> and there is a single source file
named the same as the PROG.
o Omit MAN when using <bsd.prog.mk> and the manual page is named the
same as the PROG, and is in section 1.
o All variable assignments are spelled "VAR=", i.e., no space between
the variable name and the =. Keep values sorted alphabetically, if
possible.
o Variables are expanded with {}, not (). Such as ${VARIABLE}.
o Do not use += to set variables that are only set once (or to set
variables for the first time).
o Do not use vertical whitespace in simple makefiles, but do use it to
group locally related things in more complex/longer ones.
o WARNS comes before CFLAGS, as it is basically a CFLAGS modifier. It
comes before CFLAGS rather than after CFLAGS so it does not get lost
in a sea of CFLAGS statements as WARNS is an important thing. The
usage of WARNS is spelled "WARNS?= ", so that it may be overridden on
the command line or in make.conf(5).
o "MK_WERROR=no" should not be used, it defeats the purpose of WARNS.
It should only be used on the command line and in special
circumstances.
o CFLAGS is spelled "CFLAGS+= ".
o Listing -D's before -I's in CFLAGS is preferred for alphabetical
ordering and to make -D's easier to see. The -D's often affect
conditional compilation, and -I's tend to be quite long. Split long
CFLAGS settings between the -D's and -I's.
o Do not use GCCisms (such as -g and -Wall) in CFLAGS.
o Typically, there is one ASCII tab between VAR= and the value in order
to start the value in column 9. An ASCII space is allowed for
variable names that extend beyond column 9. A lack of whitespace is
also allowed for very long variable names.
o .include <bsd.*.mk> goes last.
o Do not use anachronisms like $< and $@. Instead use ${.IMPSRC} or
${.ALLSRC} and ${.TARGET}.
o To not build the "foo" part of the base system, use NO_FOO, not
NOFOO.
o To optionally build something in the base system, spell the knob
WITH_FOO not WANT_FOO or USE_FOO. The latter are reserved for the
FreeBSD Ports Collection.
o For variables that are only checked with defined(), do not provide
any fake value.
The desire to express a logical grouping often means not obeying some of
the above.
EXAMPLES
The simplest program Makefile is:
PROG= foo
.include <bsd.prog.mk>
The simplest library Makefile is:
LIB= foo
SHLIB_MAJOR= 1
MAN= libfoo.3
SRCS= foo.c
.include <bsd.lib.mk>
SEE ALSO
make(1), make.conf(5), style(9)
HISTORY
This manual page is inspired from the style(9) manual page and first
appeared in FreeBSD 5.1.
AUTHORS
David O'Brien <deo@NUXI.org>
BUGS
There are few hard and fast style rules here. The style of many things
is too dependent on the context of the whole makefile, or the lines
surrounding it.
FreeBSD 15.1-STABLE-HBSD July 17, 2023 STYLE.MAKEFILE(5)