MAKE(1) OpenBSD Reference Manual MAKE(1)
NAME
make - maintain program dependencies
SYNOPSIS
make [-BPSeiknqrst] [-D variable] [-d flags] [-f makefile] [-I directory]
[-j max_jobs] [-m directory] [-V variable] [variable=value] [target
...]
DESCRIPTION
make is a program designed to simplify the maintenance of other programs.
Its input is a list of specifications as to the files upon which programs
and other files depend. If the file `BSDmakefile' exists, it is read for
this list of specifications. If it does not exist, the files `makefile'
and `Makefile' are tried in order. If the file `.depend' exists, it is
read (see mkdep(1)).
This manual page is intended as a reference document only. For a more
thorough introduction to make and makefiles, please refer to Make - A
Tutorial.
The options are as follows:
-B Try to be backwards compatible by executing a single shell per
command and by executing the commands to make the sources of a
dependency line in sequence. This is turned on by default unless
-j is used.
-D variable
Define variable to be 1, in the global context.
-d flags
Turn on debugging, and specify which portions of make are to
print debugging information. flags is one or more of the follow-
ing:
A Print all possible debugging information; equivalent to
specifying all of the debugging flags.
a Print debugging information about archive searching and
caching.
c Print debugging information about conditional evaluation.
d Print debugging information about directory searching and
caching.
f Print debugging information about the execution of for
loops. Currently a no-op.
g1 Print the input graph before making anything.
g2 Print the input graph after making everything, or before
exiting on error.
j Print debugging information about running multiple
shells.
m Print debugging information about making targets, includ-
ing modification dates.
s Print debugging information about suffix-transformation
rules.
t Print debugging information about target list mainte-
nance.
v Print debugging information about variable assignment.
-e Specify that environment variables override macro assignments
within makefiles.
-f makefile
Specify a makefile to read instead of the default `makefile' and
`Makefile'. If makefile is `-', standard input is read. Multiple
makefiles may be specified, and are read in the order specified.
-I directory
Specify a directory in which to search for makefiles and included
makefiles. The system makefile directory (or directories, see
the -m option) is automatically included as part of this list.
-i Ignore non-zero exit of shell commands in the makefile. Equiva-
lent to specifying `-' before each command line in the makefile.
-j max_jobs
Specify the maximum number of jobs that make may have running at
any one time. Turns compatibility mode off, unless the B flag is
also specified.
-k Continue processing after errors are encountered, but only on
those targets that do not depend on the target whose creation
caused the error.
-m directory
Specify a directory in which to search for sys.mk and makefiles
included via the <...> style. Multiple directories can be added
to form a search path. This path will override the default sys-
tem include path: /usr/share/mk. Furthermore, the system include
path will be appended to the search path used for "..."-style in-
clusions (see the -I option).
-n Display the commands that would have been executed, but do not
actually execute them.
-P Collate the output of a given job and display it only when the
job finishes, instead of mixing the output of parallel jobs to-
gether. This option has no effect unless -j is used too.
-q Do not execute any commands, but exit 0 if the specified targets
are up-to-date and 1, otherwise.
-r Do not use the built-in rules specified in the system makefile.
-S Stop processing when an error is encountered. Default behavior.
This is needed to negate the -k option during recursive builds.
-s Do not echo any commands as they are executed. Equivalent to
specifying `@' before each command line in the makefile.
-t Rather than re-building a target as specified in the makefile,
create it or update its modification time to make it appear up-
to-date.
-V variable
Print make's idea of the value of variable, in the global con-
text. Do not build any targets. Multiple instances of this op-
tion may be specified; the variables will be printed one per
line, with a blank line for each null or undefined variable.
variable=value
Set the value of the variable variable to value.
There are seven different types of lines in a makefile: file dependency
specifications, shell commands, variable assignments, include statements,
conditional directives, for loops, and comments.
In general, lines may be continued from one line to the next by ending
them with a backslash (`\'). The trailing newline character and initial
whitespace on the following line are compressed into a single space.
FILE DEPENDENCY SPECIFICATIONS
Dependency lines consist of one or more targets, an operator, and zero or
more sources. This creates a relationship where the targets ``depend''
on the sources and are usually created from them. The exact relationship
between the target and the source is determined by the operator that sep-
arates them. The three operators are as follows:
: A target is considered out-of-date if its modification time is less
than those of any of its sources. Sources for a target accumulate
over dependency lines when this operator is used. The target is
removed if make is interrupted.
! Targets are always re-created, but not until all sources have been
examined and re-created as necessary. Sources for a target accumu-
late over dependency lines when this operator is used. The target
is removed if make is interrupted.
:: If no sources are specified, the target is always re-created. Oth-
erwise, a target is considered out-of-date if any of its sources
has been modified more recently than the target. Sources for a
target do not accumulate over dependency lines when this operator
is used. The target will not be removed if make is interrupted.
Targets and sources may contain the shell wildcard expressions `?', `*',
`[]' and `{}'. The expressions `?', `*' and `[]' may only be used as part
of the final component of the target or source, and must be used to de-
scribe existing files. The expression `{}' need not necessarily be used
to describe existing files. Expansion is in directory order, not alpha-
betically as done in the shell.
SHELL COMMANDS
Each target may have associated with it a series of shell commands, nor-
mally used to create the target. Each of the commands in this script
must be preceded by a tab. While any target may appear on a dependency
line, only one of these dependencies may be followed by a creation
script, unless the `::' operator is used.
If the first or first two characters of the command line are `@' and/or
`-', the command is treated specially. A `@' causes the command not to
be echoed before it is executed. A `-' causes any non-zero exit status
of the command line to be ignored.
VARIABLE ASSIGNMENTS
Variables in make are much like variables in the shell, and, by tradi-
tion, consist of all upper-case letters. The five operators that can be
used to assign values to variables are as follows:
= Assign the value to the variable. Any previous value is overrid-
den.
+= Append the value to the current value of the variable.
?= Assign the value to the variable if it is not already defined.
:= Assign with expansion, i.e. expand the value before assigning it
to the variable. Normally, expansion is not done until the vari-
able is referenced.
!= Expand the value and pass it to the shell for execution and as-
sign the result to the variable. Any newlines in the result are
replaced with spaces.
Any whitespace before the assigned value is removed; if the value is be-
ing appended, a single space is inserted between the previous contents of
the variable and the appended value.
Variables are expanded by surrounding the variable name with either curly
braces (`{}') or parentheses (`()') and preceding it with a dollar sign
(`$'). If the variable name contains only a single letter, the surround-
ing braces or parentheses are not required. This shorter form is not
recommended.
Variable substitution occurs at two distinct times, depending on where
the variable is being used. Variables in dependency lines are expanded
as the line is read. Variables in shell commands are expanded when the
shell command is executed.
The four different classes of variables (in order of increasing prece-
dence) are:
Environment variables
Variables defined as part of make's environment.
Global variables
Variables defined in the makefile or in included makefiles.
Command line variables
Variables defined as part of the command line.
Local variables
Variables that are defined specific to a certain target. The
seven local variables are as follows:
.ALLSRC The list of all sources for this target; also known as
`>'.
.ARCHIVE The name of the archive file; also known as `!'.
.IMPSRC The name/path of the source from which the target is to
be transformed (the ``implied'' source); also known as
`<'.
.MEMBER The name of the archive member; also known as `%'.
.OODATE The list of sources for this target that were deemed
out-of-date; also known as `?'.
.PREFIX The file prefix of the file, containing only the file
portion, no suffix or preceding directory components;
also known as `*'.
.TARGET The name of the target; also known as `@'.
The shorter forms `@', `!', `<', `%', `?', `>', and `*' are per-
mitted for backward compatibility with historical makefiles and
are not recommended. The six variables `@F', `@D', `<F', `<D',
`*F', and `*D' are permitted for compatibility with AT&T System V
UNIX makefiles and are not recommended.
Four of the local variables may be used in sources on dependency
lines because they expand to the proper value for each target on
the line. These variables are `.TARGET', `.PREFIX', `.ARCHIVE',
and `.MEMBER'.
In addition, make sets or knows about the following internal variables,
or environment variables:
$ A single dollar sign `$', i.e. `$$' expands to a single dol-
lar sign.
.MAKE The name that make was executed with (argv[0]).
.CURDIR A path to the directory where make was executed.
.OBJDIR A path to the directory where the targets are built. At
startup, make searches for an alternate directory to place
target files -- it will attempt to change into this special
directory. First, if MAKEOBJDIRPREFIX is defined, make
prepends its contents to the current directory name and tries
for the resulting directory. If that fails, make remains in
the current directory. If MAKEOBJDIRPREFIX is not defined,
make checks MAKEOBJDIR and tries to change into that directo-
ry. Should that fail, make remains in the current directory.
If MAKEOBJDIR is not defined, it tries to change into the di-
rectory named obj.${MACHINE} (see MACHINE variable). If it
still has found no special directory, make next tries the di-
rectory named obj. If this fails, make tries to prepend
/usr/obj to the current directory name. Finally, if none of
these directories are available make will settle for and use
the current directory.
.MAKEFLAGS
The environment variable MAKEFLAGS may contain anything that
may be specified on make's command line. Its contents are
stored in make's .MAKEFLAGS variable. Anything specified on
make's command line is appended to the .MAKEFLAGS variable
which is then entered into the environment as MAKEFLAGS for
all programs which make executes.
MFLAGS A shorter synonym for .MAKEFLAGS.
PWD Alternate path to the current directory. make normally sets
`.CURDIR' to the canonical path given by getcwd(2). However,
if the environment variable PWD is set and gives a path to the
current directory, then make sets `.CURDIR' to the value of
PWD instead. PWD is always set to the value of `.OBJDIR' for
all programs which make executes.
.TARGETS List of targets make is currently building.
.INCLUDES See .INCLUDES special target
.LIBS See .LIBS special target
MACHINE Name of the machine architecture make is running on, obtained
from the MACHINE environment variable, or through uname(2) if
not defined.
MACHINE_ARCH
Name of the machine architecture make was compiled for, ob-
tained from the MACHINE_ARCH environment variable, or defined
at compilation time.
Variable expansion may be modified to select or modify each word of the
variable (where a ``word'' is whitespace delimited sequence of charac-
ters). The general format of a variable expansion is as follows:
{variable[:modifier[:...]]}
Each modifier begins with a colon and one of the following special char-
acters. The colon may be escaped with a backslash (`\').
E Replaces each word in the variable with its suffix.
H Replaces each word in the variable with everything but the
last component.
L Replaces each word in the variable with its lower case equiv-
alent.
U Replaces each word in the variable with its upper case equiv-
alent.
Mpattern Select only those words that match the rest of the modifier.
The standard shell wildcard characters (`*', `?', and `[]')
may be used. The wildcard characters may be escaped with a
backslash (`\').
Npattern This is identical to M, but selects all words which do not
match the rest of the modifier.
Q Quotes every shell meta-character in the variable, so that it
can be passed safely through recursive invocations of make.
R Replaces each word in the variable with everything but its
suffix.
S/old_string/new_string/[1g]
Modify the first occurrence of old_string in the variable's
value, replacing it with new_string. If a `g' is appended to
the last slash of the pattern, all occurrences in each word
are replaced. If a `1' is appended to the last slash of the
pattern, only the first word is affected. If old_string be-
gins with a caret (`^'), old_string is anchored at the begin-
ning of each word. If old_string ends with a dollar sign
(`$'), it is anchored at the end of each word. Inside
new_string, an ampersand (`&') is replaced by old_string
(without any `^' or `$'). Any character may be used as a de-
limiter for the parts of the modifier string. The anchoring,
ampersand and delimiter characters may be escaped with a
backslash (`\').
Variable expansion occurs in the normal fashion inside both
old_string and new_string with the single exception that a
backslash is used to prevent the expansion of a dollar sign
(`$'), not a preceding dollar sign as is usual.
C/pattern/replacement/[1g]
The C modifier is just like the S modifier except that the
old and new strings, instead of being simple strings, are a
regular expression (see regex(3)) and an ed(1)-style re-
placement string. Normally, the first occurrence of the pat-
tern in each word of the value is changed. The `1' modifier
causes the substitution to apply to at most one word; the `g'
modifier causes the substitution to apply to as many in-
stances of the search pattern as occur in the word or words
it is found in. Note that `1' and `g' are orthogonal; the
former specifies whether multiple words are potentially af-
fected, the latter whether multiple substitutions can poten-
tially occur within each affected word.
T Replaces each word in the variable with its last component.
old_string=new_string
This is the AT&T System V UNIX style variable substitution.
It must be the last modifier specified. If old_string or
new_string do not contain the pattern matching character %
then it is assumed that they are anchored at the end of each
word, so only suffixes or entire words may be replaced. Oth-
erwise % is the substring of old_string to be replaced in
new_string
INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
Makefile inclusion, conditional structures and for loops reminiscent of
the C programming language are provided in make. All such structures are
identified by a line beginning with a single dot (`.') character. Files
are included with either `.include <file>' or `.include "file"'. Vari-
ables between the angle brackets or double quotes are expanded to form
the file name. If angle brackets are used, the included makefile is ex-
pected to be in the system makefile directory. If double quotes are
used, the including makefile's directory and any directories specified
using the -I option are searched before the system makefile directory.
Conditional expressions are also preceded by a single dot as the first
character of a line. The possible conditionals are as follows:
.undef variable
Un-define the specified global variable. Only global variables
may be un-defined.
.if [!]expression [operator expression ...]
Test the value of an expression.
.ifdef [!]variable [operator variable ...]
Test the value of a variable.
.ifndef [!]variable [operator variable ...]
Test the value of a variable.
.ifmake [!]target [operator target ...]
Test the target being built.
.ifnmake [!]target [operator target ...]
Test the target being built.
.else Reverse the sense of the last conditional.
.elif [!]expression [operator expression ...]
A combination of `.else' followed by `.if'.
.elifdef [!]variable [operator variable ...]
A combination of `.else' followed by `.ifdef'.
.elifndef [!]variable [operator variable ...]
A combination of `.else' followed by `.ifndef'.
.elifmake [!]target [operator target ...]
A combination of `.else' followed by `.ifmake'.
.elifnmake [!]target [operator target ...]
A combination of `.else' followed by `.ifnmake'.
.endif End the body of the conditional.
The operator may be any one of the following:
|| logical OR
&& Logical AND; of higher precedence than ``''.
As in C, make will only evaluate a conditional as far as is necessary to
determine its value. Parentheses may be used to change the order of
evaluation. The boolean operator `!' may be used to logically negate an
entire conditional. It is of higher precedence than `&&'.
The value of expression may be any of the following:
defined Takes a variable name as an argument and evaluates to true if
the variable has been defined.
make Takes a target name as an argument and evaluates to true if
the target was specified as part of make's command line or
was declared the default target (either implicitly or explic-
itly, see .MAIN) before the line containing the conditional.
empty Takes a variable, with possible modifiers, and evaluates to
true if the expansion of the variable would result in an emp-
ty string.
exists Takes a file name as an argument and evaluates to true if the
file exists. The file is searched for on the system search
path (see .PATH).
target Takes a target name as an argument and evaluates to true if
the target has been defined.
expression may also be an arithmetic or string comparison. Variable ex-
pansion is performed on both sides of the comparison, after which the in-
tegral values are compared. A value is interpreted as hexadecimal if it
is preceded by 0x, otherwise it is decimal; octal numbers are not sup-
ported. The standard C relational operators are all supported. If after
variable expansion, either the left or right hand side of a `==' or `!='
operator is not an integral value, then string comparison is performed
between the expanded variables. If no relational operator is given, it
is assumed that the expanded variable is being compared against 0.
When make is evaluating one of these conditional expressions, and it en-
counters a word it doesn't recognize, either the ``make'' or ``defined''
expression is applied to it, depending on the form of the conditional.
If the form is `.ifdef' or `.ifndef', the ``defined'' expression is ap-
plied. Similarly, if the form is `.ifmake' or `.ifnmake', the ``make''
expression is applied.
If the conditional evaluates to true the parsing of the makefile contin-
ues as before. If it evaluates to false, the following lines are
skipped. In both cases this continues until a `.else' or `.endif' is
found.
For loops are typically used to apply a set of rules to a list of files.
The syntax of a for loop is:
.for variable in expression
<make-rules>
.endfor
After the for expression is evaluated, it is split into words. The itera-
tion variable is successively set to each word, and substituted in the
make-rules inside the body of the for loop.
COMMENTS
Comments begin with a hash (`#') character, anywhere but in a shell com-
mand line, and continue to the end of the line.
SPECIAL SOURCES
.IGNORE Ignore any errors from the commands associated with this tar-
get, exactly as if they all were preceded by a dash (`-').
.MADE Mark all sources of this target as being up-to-date.
.MAKE Execute the commands associated with this target even if the
-n or -t options were specified. Normally used to mark re-
cursive make's.
.NOTMAIN Normally make selects the first target it encounters as the
default target to be built if no target was specified. This
source prevents this target from being selected.
.OPTIONAL If a target is marked with this attribute and make can't fig-
ure out how to create it, it will ignore this fact and assume
the file isn't needed or already exists.
.PRECIOUS When make is interrupted, it removes any partially made tar-
gets. This source prevents the target from being removed.
.SILENT Do not echo any of the commands associated with this target,
exactly as if they all were preceded by an at sign (`@').
.USE Turn the target into make's version of a macro. When the
target is used as a source for another target, the other tar-
get acquires the commands, sources, and attributes (except
for .USE) of the source. If the target already has commands,
the .USE target's commands are appended to them.
.WAIT If special .WAIT source is appears in a dependency line, the
sources that precede it are made before the sources that suc-
ceed it in the line. Loops are not being detected and targets
that form loops will be silently ignored.
SPECIAL TARGETS
Special targets may not be included with other targets, i.e. they must be
the only target specified.
.BEGIN Any command lines attached to this target are executed before
anything else is done.
.DEFAULT This is sort of a .USE rule for any target (that was used on-
ly as a source) that make can't figure out any other way to
create. Only the shell script is used. The .IMPSRC variable
of a target that inherits .DEFAULT's commands is set to the
target's own name.
.END Any command lines attached to this target are executed after
everything else is done.
.IGNORE Mark each of the sources with the .IGNORE attribute. If no
sources are specified, this is the equivalent of specifying
the -i option.
.INCLUDES A list of suffixes that indicate files that can be included
in a source file. The suffix must have already been declared
with .SUFFIXES, any suffix so declared will have the directo-
ries on its search path (see .PATH) placed in the .INCLUDES
special variable, each preceded by a -I flag.
.INTERRUPT If make is interrupted, the commands for this target will be
executed.
.LIBS This does for libraries what .INCLUDES does for include
files, except that the flag used is -L.
.MAIN If no target is specified when make is invoked, this target
will be built. This is always set, either explicitly, or im-
plicitly when make selects the default target, to give the
user a way to refer to the default target on the command
line.
.MAKEFLAGS This target provides a way to specify flags for make when the
makefile is used. The flags are as if typed to the shell,
though the -f option will have no effect.
.NOTPARALLEL
Disable parallel mode.
.NO_PARALLEL
Same as above, for compatibility with other pmake variants.
.ORDER The named targets are made in sequence.
.PATH The sources are directories which are to be searched for
files not found in the current directory. If no sources are
specified, any previously specified directories are deleted.
.PATHsuffix
The sources are directories which are to be searched for suf-
fixed files not found in the current directory. make first
searches the suffixed search path, before reverting to the
default path if the file is not found there.
.PHONY Apply the .PHONY attribute to any specified sources. Targets
with this attribute are always considered to be out of date.
.PRECIOUS Apply the .PRECIOUS attribute to any specified sources. If
no sources are specified, the .PRECIOUS attribute is applied
to every target in the file.
.SILENT Apply the .SILENT attribute to any specified sources. If no
sources are specified, the .SILENT attribute is applied to
every command in the file.
.SUFFIXES Each source specifies a suffix to make. If no sources are
specified, any previous specified suffices are deleted.
COMPATIBILITY
Older versions of make used MAKE instead of MAKEFLAGS. This was removed
for POSIX compatibility. The internal variable MAKE is set to the same
value as .MAKE, support for this may be removed in the future.
Most of the more esoteric features of make should probably be avoided for
greater compatibility.
ENVIRONMENT
make uses the following environment variables, if they exist: MACHINE,
MACHINE_ARCH, MAKEFLAGS, MAKEOBJDIR, MAKEOBJDIRPREFIX, and PWD.
FILES
.depend list of dependencies
BSDmakefile list of dependencies
Makefile list of dependencies
makefile list of dependencies
sys.mk system makefile
/usr/share/mk system makefile directory default MAKEOBJDIRPREFIX
directory.
BUGS
The determination of .OBJDIR is contorted to the point of absurdity.
In the presence of several .MAIN special targets, make silently ignores
all but the first.
.TARGETS is not set to the default target when make is invoked without a
target name and no MAIN special target exists.
The evaluation of expression in a test is very simple-minded. Currently,
the only form that works is `.if ${VAR} op something' For instance, you
should write tests as `.if ${VAR} = string' not the other way around,
which doesn't work.
For loops are expanded before tests, so a fragment such as:
.for TMACHINE in ${SHARED_ARCHS}
.if ${TMACHINE} = ${MACHINE}
...
.endif
.fi
won't work, and should be rewritten the other way around.
SEE ALSO
mkdep(1)
HISTORY
A make command appeared in Version 7 AT&T UNIX.
OpenBSD 2.6 March 19, 1994 11
Source: OpenBSD 2.6 man pages. Copyright: Portions are copyrighted by BERKELEY SOFTWARE DESIGN, INC., The Regents of the University of California, Massachusetts Institute of Technology, Free Software Foundation, FreeBSD Inc., and others. |