make - maintain program dependencies
make [-BeiknPqrSst] [-D variable] [-d flags] [-f makefile]
[-I directory]
[-j max_jobs] [-m directory] [-V variable] [NAME=value]
[target ...]
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 in addition to the makefile (see mkdep(1)).
The handling of `BSDmakefile' and `.depend' are BSD extensions.
Standard options are as follows:
-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 Ignore non-zero exit of shell commands in the makefile. Equivalent
to specifying `-' before each command line in
the makefile.
-k Continue processing after errors are encountered,
but only on
those targets that do not depend on the target whose
creation
caused the error.
-n Display the commands that would have been executed,
but do not
actually execute them.
-q Do not execute any commands, but exit with status 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. This
is the default
behavior. This is needed to negate the -k option during
recursive builds.
-s Do not echo 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 upto-date.
NAME=value
Set the value of the variable NAME to value.
Extended 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.
-d flags
Turn on debugging, and specify which portions of
make are to
print debugging information. flags is one or more
of the following:
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 expansion of for
loops.
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.
l Print commands in Makefile targets regardless of whether
or not they are prefixed by @. Also known
as loud behavior.
m Print debugging information about making
targets, including
modification dates.
s Print debugging information about suffixtransformation
rules.
t Print debugging information about target
list maintenance.
v Print debugging information about variable
assignment.
-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.
-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.
-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 system
include path: /usr/share/mk. Furthermore, the
system include
path will be appended to the search path used for
"..."-style inclusions
(see the -I option).
-P Collate the output of a given job and display it only when the
job finishes, instead of mixing the output of parallel jobs together.
This option has no effect unless -j is used
too.
-V variable
Print make's idea of the value of variable. Do not
build any
targets. Multiple instances of this option may be
specified; the
variables will be printed one per line, with a blank
line for
each null or undefined variable.
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. Of these,
include
statements, conditional directives and for loops are extensions.
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 [Toc] [Back] 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 separates
them. Note that the use of several targets is merely
a shorthand
for duplicate rules. Specifically,
target1 target2: depa depb
cmd1
cmd2
is just a short form of
target1: depa depb
cmd1
cmd2
target2: depa depb
cmd1
cmd2
make does not support Solaris syntax for true multiple targets:
target1 + target2: depa depb
cmd1
cmd2
The 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 accumulate
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 recreated. Otherwise,
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.
The :: operator is a fairly standard extension. The ! operator is a BSD
extension.
As an extension, 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 describe existing files. The expression
`{}' need not
necessarily be used to describe existing files. Expansion
is in directory
order, not alphabetically as done in the shell.
For maximum portability, target names should only consist of
periods, underscores,
digits and alphabetic characters.
Each target may have associated with it a series of shell
commands, normally
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 a command line begins with a combination of the characters, `@', `-'
and/or `+', the command is treated specially:
`@' causes the command not to be echoed before it is executed.
`-' causes any non-zero exit status of the command line to
be ignored.
`+' causes the command to be executed even if -n has been
specified.
(This can be useful to debug recursive Makefiles.)
The command is always executed using /bin/sh in "set -e"
mode.
Variables in make are much like variables in the shell, and,
by tradition,
consist of all upper-case letters. They are also
called `macros'
in various texts. For portability, only periods, underscores, digits and
letters should be used for variable names. 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 overridden.
:= Assign with expansion, i.e., expand the value before
assigning it
to the variable (extension).
+= Append the value to the current value of the variable (extension).
?= Assign the value to the variable if it is not already defined
(BSD extension). Normally, expansion is not done
until the variable
is referenced.
!= Expand the value and pass it to the shell for execution and assign
the result to the variable. Any newlines in
the result are
replaced with spaces (BSD extension).
Any whitespace before the assigned value is removed; if the
value is being
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 surrounding
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 precedence)
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. Standard
local variables are as follows:
@ The name of the target.
% The name of the archive member (only valid
for library
rules).
! The name of the archive file (only valid
for library
rules).
? The list of prerequisites for this target
that were
deemed out-of-date.
< The name of the source from which this
target is to be
built, if a valid implied rule (suffix
rule) is in
scope.
* The file prefix of the file, containing
only the file
portion, no suffix or preceding directory
components.
The six variables `@F', `@D', `<F', `<D', `*F', and
`*D' yield
the "filename" and "directory" parts of the corresponding macros.
For maximum compatibility, `<' should only be used
for actual implied
rules. It is also set when there is an implied rule that
matches the current dependency in scope. That is,
in
.SUFFIXES: .c.o
file.o: file.c
cmd1 $<
.c.o:
cmd2
building file.o will execute "cmd1 file.c".
As an extension, make supports the following local
variables:
> The list of all sources for this target.
.ALLSRC Synonym for `>'.
.ARCHIVE Synonym for `!'.
.IMPSRC Synonym for `<'.
.MEMBER Synonym for `%'.
.OODATE Synonym for `?'.
.PREFIX Synonym for `*'.
.TARGET Synonym for `@'.
These variables may be used on the dependency half
of dependency
lines, when they make sense.
In addition, make sets or knows about the following internal
variables,
or environment variables:
$ A single dollar sign `$', i.e., `$$' expands to a
single dollar
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 directory.
Should that fail, make remains in the current directory.
If MAKEOBJDIR is not defined, it tries to change
into the directory
named obj.${MACHINE} (see MACHINE variable). If it
still has found no special directory, make next
tries the directory
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(3). 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(3) if
not defined.
MACHINE_ARCH
Name of the machine architecture make was compiled for, obtained
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 ``word'' is a whitespace delimited sequence
of characters).
The general format of a variable expansion is as
follows:
{variable[:modifier[:...]]}
Each modifier begins with a colon and one of the following
special characters.
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 equivalent.
:U Replaces each word in the variable with its upper
case equivalent.
: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 begins with a
caret (`^'), old_string is anchored at the beginning
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
`$'). Any
character may be used as a delimiter for the parts
of the modifier
string. The anchoring, ampersand and delimiter
characters may
be escaped with a backslash (`').
Variable expansion occurs in the normal fashion inside both
old_string and new_string with the single exception
that a backslash
is used to prevent the expansion of a dollar
sign (`$'),
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 replacement string.
Normally, the first occurrence of the pattern 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 instances 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
affected, the latter whether multiple substitutions can
potentially 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. Otherwise
% is the
substring of old_string to be replaced in
new_string.
All modifiers are BSD extensions, except for the standard
AT&T System V
UNIX style variable substitution.
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.
Whitespace characters may follow this dot, e.g.,
.include <file>
and
. include <file>
are identical constructs. Files are included with either
`.include
<file>' or `.include "file"'. Variables between the angle
brackets or
double quotes are expanded to form the file name. If angle
brackets are
used, the included makefile is expected 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 explicitly, 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
empty
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 expansion
is performed on both sides of the comparison, after
which the integral
values are compared. A value is interpreted as hexadecimal if it
is preceded by 0x, otherwise it is decimal; octal numbers
are not supported.
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 encounters
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 applied.
Similarly, if the form is `.ifmake' or `.ifnmake',
the ``make''
expression is applied.
If the conditional evaluates to true the parsing of the
makefile continues
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 [variable ...] in expression
<make-rules>
.endfor
After the for expression is evaluated, it is split into
words. On each
iteration of the loop, one word is assigned to each
variable, in order,
and these variables are substituted in the make-rules inside
the body of
the for loop. The number of words must match the number of
iteration
variables; that is, if there are three iteration variables,
the number of
words must be a multiple of three.
Loops and conditional expressions may nest arbitrarily, but
they may not
cross include file boundaries.
Comments begin with a hash (`#') character, anywhere but in
a shell command
line, and continue to the end of the line.
.IGNORE Ignore any errors from the commands associated
with this target,
exactly as if they all were preceded by a
dash (`-').
.MADE Mark all sources of this target as being up-todate.
.MAKE Execute the commands associated with this target
even if the
-n or -t options were specified. Normally used
to mark recursive
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 figure
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 targets.
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 target
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 .WAIT appears in a dependency line, the
sources that precede
it are made before the sources that succeed
it in the
line. Loops are not detected and targets that
form loops will
be silently ignored.
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
only 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
directories in 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
implicitly 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
suffixed 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 previously specified suffixes
are deleted.
make uses the following environment variables, if they exist: MACHINE,
MACHINE_ARCH, MAKEFLAGS, MAKEOBJDIR, MAKEOBJDIRPREFIX, and
PWD. make also
ignores and unsets CDPATH.
.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
/usr/obj default MAKEOBJDIRPREFIX directory
ed(1), mkdep(1), sh(1), getcwd(3), regex(3), uname(3)
"Make -- A Tutorial", /usr/share/doc/psd/12.make/.
make mostly conforms to the Single Unix Specification, Version 2, with
some noted extensions and a few problems.
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.
A make command appeared in Version 7 AT&T UNIX.
The determination of .OBJDIR is contorted to the point of
absurdity.
If the same target is specified several times in normal dependency rules,
make silently ignores all commands after the first non empty
set of commands,
e.g., in
a:
@echo "Executed"
a:
@echo "Bad luck"
@echo "Bad luck" will be silently ignored.
.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,
tests should be written 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
.endfor
won't work, and should be rewritten the other way around.
When handling pre-BSD 4.4 archives, make may erroneously
mark archive
members as out of date if the archive name was truncated.
The handling of `;' and other special characters in tests
may be utterly
bogus. For instance, in
A=abcd;c.c
.if ${A:R} == "abcd;c"
the test will never match, even though the value is correct.
The conditional handler is incredibly lame. Junk such as
.if defined anything goes (A)
will be accepted silently.
In a .for loop, only the variable value is used; assignments
will be
evaluated later, e.g., in
.for I in a b c d
I:=${I:S/a/z}
A+=$I
.endfor
`A' will evaluate to a b c d after the loop, not z b c d.
The `+' command modificator is ignored in parallel make
mode.
OpenBSD 3.6 March 19, 1994
[ Back ] |
