.\" Copyright (c) 2002-2003 David O'Brien .\" 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. .\" .Dd July 17, 2023 .Dt STYLE.MAKEFILE 5 .Os .Sh NAME .Nm style.Makefile .Nd .Fx .Pa Makefile file style guide .Sh DESCRIPTION This file specifies the preferred style for makefiles in the .Fx source tree. .Bl -bullet .It .Cm .PATH : comes first if needed, and is spelled .Dq Li ".PATH: " , with a single .Tn ASCII space after a colon. Do not use the .Va VPATH variable. .It Special variables (i.e., .Va LIB , SRCS , MLINKS , etc.) are listed in order of .Dq product , then building and installing a binary. Special variables may also be listed in .Dq build order: i.e., ones for the primary program (or library) first. The general .Dq product order is: .Va PROG Ns / Ns Oo Va SH Oc Ns Va LIB Ns / Ns Va SCRIPTS .Va FILES .Va LINKS .Va MAN .Va MLINKS .Va INCS .Va SRCS .Va WARNS .Va CSTD .Va CFLAGS .Va DPADD .Va LDADD . The general .Dq build order is: .Va PROG Ns / Ns Oo Va SH Oc Ns Va LIB Ns / Ns Va SCRIPTS .Va SRCS .Va WARNS .Va CSTD .Va CFLAGS .Va DPADD .Va LDADD .Va INCS .Va FILES .Va LINKS .Va MAN .Va MLINKS . .It Omit .Va SRCS when using .In bsd.prog.mk and there is a single source file named the same as the .Va PROG . .It Omit .Va MAN when using .In bsd.prog.mk and the manual page is named the same as the .Va PROG , and is in section 1. .It All variable assignments are spelled .Dq Va VAR Ns Ic = , i.e., no space between the variable name and the .Ic = . Keep values sorted alphabetically, if possible. .It Variables are expanded with .Sy {} , not .Sy () . Such as .Va ${VARIABLE} . .It Do not use .Ic += to set variables that are only set once (or to set variables for the first time). .It Do not 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. The usage of .Va WARNS is spelled .Dq Li "WARNS?= " , so that it may be overridden on the command line or in .Xr make.conf 5 . .It .Dq Li "MK_WERROR=no" should not be used, it defeats the purpose of .Va WARNS . It should only be used on the command line and in special circumstances. .It .Va CFLAGS is spelled .Dq Li "CFLAGS+= " . .It Listing .Fl D Ns 's before .Fl I Ns 's in .Va CFLAGS is preferred for alphabetical ordering and to make .Fl D Ns 's easier to see. The .Fl D Ns 's often affect conditional compilation, and .Fl I Ns 's tend to be quite long. Split long .Va CFLAGS settings between the .Fl D Ns 's and .Fl I Ns 's. .It Do not use GCCisms (such as .Fl g and .Fl Wall ) in .Va CFLAGS . .It Typically, there is one .Tn ASCII tab between .Va VAR Ns Ic = and the value in order to start the value in column 9. An .Tn ASCII space is allowed for variable names that extend beyond column 9. A lack of whitespace is also allowed for very long variable names. .It .Ic .include In bsd.*.mk goes last. .It Do not use anachronisms like .Va $< and .Va $@ . Instead use .Va ${.IMPSRC} or .Va ${.ALLSRC} and .Va ${.TARGET} . .It To not build the .Dq foo part of the base system, use .Va NO_FOO , not .Va NOFOO . .It To optionally build something in the base system, spell the knob .Va WITH_FOO not .Va WANT_FOO or .Va USE_FOO . The latter are reserved for the .Fx Ports Collection. .It For variables that are only checked with .Fn defined , do not provide any fake value. .El .Pp The desire to express a logical grouping often means not obeying some of the above. .Sh EXAMPLES The simplest program .Pa Makefile is: .Bd -literal -offset indent PROG= foo \&.include .Ed .Pp The simplest library .Pa Makefile is: .Bd -literal -offset indent LIB= foo SHLIB_MAJOR= 1 MAN= libfoo.3 SRCS= foo.c \&.include .Ed .Sh SEE ALSO .Xr make 1 , .Xr make.conf 5 , .Xr style 9 .Sh HISTORY This manual page is inspired from the same source as .Xr style 9 manual page in .Fx . .Sh 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.