xref: /freebsd/share/man/man5/style.Makefile.5 (revision 91c8d237228eaf3fac1b4ec4183a83e13bbc6e6b)

.\" Copyright (c) 2002-2003 David O'Brien <obrien@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the author nor the names of any contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL DAVID O'BRIEN OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd November 27, 2002
.Dt STYLE.MAKEFILE 5
.Os
.Sh NAME
.Nm style.Makefile
.Nd "FreeBSD Makefile file style guide"
.Sh DESCRIPTION
This file specifies the preferred style for Makefiles in the
.Fx
source tree.
.Pp
.Bl -bullet -compact
.It
All Makefiles should have an SCM ID at the start of the file,
followed by a blank line.
.Bd -literal
# $FreeBSD$

.Ed
.It
\&.PATH: comes next if needed, and is spelled
.Pa ".PATH: <ascii space>"
.It
Special variables (i.e., LIB, SRCS, MLINKS, etc..) are listed in order
of 'product',
then building and installing a binary.
The general order is:
.Va PROG/LIB/SCRIPT
.Va FILES
.Va LINKS
.Va [NO]MAN
.Va MLINK
.Va INCS
.Va SRC
.Va WARNS
.Va CFLAGS
.Va DPADD
.Va LDADD
.It
Omit
.Va SRC
when using
.Pa bsd.prog.mk
and there is a single source file named the same as the
.Va PROG .
.It
Omit
.Va MAN
when using
.Pa bsd.prog.mk
and the man page is named the same as the
.Va PROG
and is in section 1.
.It
All variable assignment is spelled
.Pa "VAR=" ,
i.e. no space between the variable name and the
.Pa "=" .
Keep values sorted alphabetically, if possible.
.It
Don't use
.Pa "+="
to set variables that are only set once
(or to set variables for the first time).
.It
Don't use vertical whitespace in simple Makefiles,
but do use it to group locally related things in more complex/longer ones.
.It
.Va WARNS
comes before
.Va CFLAGS ,
as it is basically a
.Va CFLAGS
modifier.
It comes before
.Va CFLAGS
rather than after
.Va CFLAGS
so it does not get lost in a sea of
.Va CFLAGS
statements as
.Va WARNS
is an important thing.
.It
Unconditional
.Pa "NO_WERROR=yes"
should not be used.
It defeats the purpose of
.Va WARNS .
.It
.Va CFLAGS
is spelled
.Pa "CFLAGS+=<ascii space>" .
.It
Listing -D's before -I's in
.Va 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.
.It
Don't use GCC'isms (such as -g and -Wall) in
.Va CFLAGS .
.It
Typically there is one <ascii tab> between
.Pa "VAR="
and the value in order to start the value in column 9.
An <ascii space> is allowed for VAR names that extend beyond column 9.
A lack of whitespace also is allowed for very long VAR names.
.Bd -literal
.It
".include <bsd.*.mk>"
goes last.
.El
.Ed
.Pp
The desire to express a logical grouping often means not obeying some of the
above.
.Pp
The simplist program Makefile is:
.Bd -literal
# $FreeBSD$

PROG=	foo

\&.include <bsd.prog.mk>
.Pp
The simplist library Makefile is:
.Bd -literal
# $FreeBSD$

LIB=	foo
SHLIB_MAJOR= 1
MAN=	libfoo.3
SRCS=	foo.c

\&.include <bsd.lib.mk>
.Pp
.Sh SEE ALSO
.Xr make 1
.Xr style 9
.Sh HISTORY
This man page is inspired from the same source as
.Xr style 9
man page in
.Fx .
.Sh BUGS
There are few hard and fast style rules here.
The style of many things are too dependent on the context of the whole Makefile,
or the lines surrounding it.