make -- maintain program dependencies
make [-BPSXeiknqrstv] [-C directory] [-D variable] [-d flags]
[-E variable] [-f makefile] [-I directory] [-j max_jobs]
[-m directory] [-V variable] [variable=value] [target ...]
The make utility is a program designed to simplify the maintenance of
other programs. Its input is a list of specifications describing dependency
relationships between the generation of files and programs. The
first of BSDmakefile, makefile and Makefile that can be found in either
the current directory or a special object directory (see .OBJDIR) will be
read for this list of specifications. If the file .depend can be found,
it is also 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.
-C directory
Change to directory before reading the makefiles or doing anything
else. If multiple -C options are specified, each is interpreted
relative to the previous one: -C / -C etc is equivalent to
-C /etc.
-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. Argument 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 execution 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 Makefiles regardless of whether or not
they are prefixed by @ or other "quiet" flags. Also
known as "loud" behavior.
m Print debugging information about making targets, including
modification dates.
s Print debugging information about suffix-transformation
rules.
t Print debugging information about target list maintenance.
v Print debugging information about variable assignment.
-E variable
Specify a variable whose environment value (if any) will override
macro assignments within makefiles.
-e Specify that environment values override macro assignments within
makefiles for all variables.
-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. Equivalent
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 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).
-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
together. 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 behaviour.
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 upto-date.
-V variable
Print make's idea of the value of variable, in the global context.
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.
-v Be extra verbose. For multi-job makes, this will cause file banners
to be generated.
-X When using the -V option to print the values of variables, do not
recursively expand the values.
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 [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. 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 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 re-created. 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.
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.
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 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.
Variables in make are much like variables in the shell, and, by tradition,
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 overridden.
+= 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 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.
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. 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 permitted
for backward compatibility 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 dollar
sign.
MAKE The name that make was executed with (argv[0]).
.CURDIR A path to the directory where make was executed. The make
utility sets .CURDIR to the canonical path given by getcwd(3).
.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 and will search this directory for makefiles not
found in the current directory. The following directories are
tried in order:
1. ${MAKEOBJDIRPREFIX}/`pwd`
2. ${MAKEOBJDIR}
3. obj.${MACHINE}
4. obj
5. /usr/obj/`pwd`
The first directory that make successfully changes into is
used. If either MAKEOBJDIRPREFIX or MAKEOBJDIR is set in the
environment but make is unable to change into the corresponding
directory, then the current directory is used without
checking the remainder of the list. If they are undefined and
make is unable to change into any of the remaining three
directories, then the current directory is used.
The make utility sets .OBJDIR to the canonical path given by
getcwd(3).
.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 synonym for .MAKEFLAGS provided for backward compatibility.
.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,
defined at compilation time.
VPATH Makefiles may assign a colon-delimited list of directories to
VPATH. These directories will be searched for source files by
make after it has finished parsing all input makefiles.
Variable expansion may be modified to select or modify each word of the
variable (where a ``word'' is 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 (`\').
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 an
extended regular expression (see re_format(7)) 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.
E Replaces each word in the variable with its suffix.
H Replaces each word in the variable with everything but the
last component.
L Converts variable to lower-case letters.
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.
O Order every word in the variable alphabetically.
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/[g]
Modify the first occurrence of old_string in each word of 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 old_string begins with a caret
(`^'), old_string is anchored at the beginning of each word.
If old_string ends with a dollar sign (`$'), it is anchored
at the end of each word. Inside new_string, an ampersand
(`&') is replaced by old_string. Any character may be used
as a delimiter for the parts of the modifier string. The
anchoring, ampersand, and delimiter characters may be escaped
with a backslash (`\').
Variable expansion occurs in the normal fashion inside both
old_string and new_string with the single exception that a
backslash is used to prevent the expansion of a dollar sign
(`$'), not a preceding dollar sign as is usual.
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
T Replaces each word in the variable with its last component.
U Converts variable to upper-case letters.
DIRECTIVES, CONDITIONALS, AND FOR LOOPS
Directives, conditionals, 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. The following directives
are supported:
.include <file>
.include "file"
Include the specified makefile. 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.
.undef variable
Un-define the specified global variable. Only global variables
may be un-defined.
.error message
Terminate processing of the makefile immediately. The filename
of the makefile, the line on which the error was encountered and
the specified message are printed to standard output and make
terminates with exit code 1. Variables in the message are
expanded.
Conditionals are used to determine which parts of the Makefile to
process. They are used similarly to the conditionals supported by the C
pre-processor. The following conditionals are supported:
.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.
An expression may also be an arithmetic or string comparison, with the
left-hand side being a variable expansion. 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 .if, .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 in expression
<make-rules>
.endfor
After the for expression is evaluated, it is split into words. The iteration
variable is successively set to each word, and substituted in the
make-rules inside the body of the for loop.
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 (`-').
.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 special .WAIT source is appears in a dependency line, the
sources that precede it are made before the sources that succeed
it in the line. Loops are not being 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
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
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.
Where possible, use of .PATH is preferred over use of the
VPATH variable.
.PATHsuffix
The sources are directories which are to be searched for suffixed
files not found in the current directory. The make
utility first searches the suffixed search path, before
reverting to the default path if the file is not found there.
This form is required for .LIBS and .INCLUDES to work.
.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.
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.
The make utility uses the following environment variables, if they exist:
MACHINE, MAKE, MAKEFLAGS, MAKEOBJDIR, and MAKEOBJDIRPREFIX.
.depend list of dependencies
Makefile list of dependencies
makefile list of dependencies
obj object directory
sys.mk system makefile (processed before any other
file, including makefile and Makefile)
/usr/share/mk system makefile directory
/usr/share/doc/psd/12.make PMake tutorial
/usr/obj default MAKEOBJDIRPREFIX directory.
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
.endfor
won't work, and should be rewritten the other way around.
The parsing code is broken with respect to handling a semicolon after a
colon, so a fragment like this will fail:
HDRS= foo.h bar.h
all:
.for h in ${HDRS:S;^;${.CURDIR}/;}
...
.endfor
mkdep(1), make.conf(5)
PMake - A Tutorial. in /usr/share/doc/psd/12.make
A make command appeared in PWB UNIX.
FreeBSD 5.2.1 June 13, 1995 FreeBSD 5.2.1 [ Back ] |
