NAME
make
- maintain program dependencies
SYNOPSIS
make
[-BeikNnqrstWX]
[-D variable]
[-d flags]
[-f makefile]
[-I directory]
[-J private]
[-j max_jobs]
[-m directory]
[-T file]
[-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 no
-f makefile
makefile option is given,
make
will try to open
`
makefile
'
then
`
Makefile
'
in order to find the specifications.
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 description of
make
and makefiles, please refer to
make
will prepend the contents of the
MAKEFLAGS
environment variable to the command line arguments before parsing them.
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.
- -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.
Unless the flags are preceded by
`-'
they are added to the
MAKEFLAGS
environment variable and will be processed by any child make processes.
By default, debugging information is printed to standard error,
but this can be changed using the
F
debugging flag.
The debugging output is always unbuffered; in addition, if debugging
is enabled but debugging output is not directed to standard output,
then the standard output is line buffered.
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.
- e
-
Print debugging information about failed commands and targets.
- F+[.blm Ppfilename
- ]
Specify where debugging output is written.
This must be the last flag, because it consumes the remainder of
the argument.
If the character immediately after the
`F'
flag is
`+',
then the file will be opened in append mode;
otherwise the file will be overwritten.
If the file name is
`stdout'
or
`stderr'
then debugging output will be written to the
standard output or standard error output file descriptors respectively
(and the
`+'
option has no effect).
Otherwise, the output will be written to the named file.
If the file name ends
`.%d'
then the
`%d'
is replaced by the pid.
- f
-
Print debugging information about loop evaluation.
- g1
-
Print the input graph before making anything.
- g2
-
Print the input graph after making everything, or before exiting
on error.
- g3
-
Print the input graph 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.
- n
-
Don't delete the temporary command scripts created in
/tmp
when running commands.
These are created via
mkstemp(3)
and have names of the form
/tmp/makeXXXXX
.
NOTE:
This can create many file in
/tmp
so use with care.
- p
-
Print debugging information about makefile parsing.
- s
-
Print debugging information about suffix-transformation rules.
- t
-
Print debugging information about target list maintenance.
- v
-
Print debugging information about variable assignment.
- x
-
Run shell commands with
-x
so the actual commands are printed as they are executed.
- -e
-
Specify that environment variables override macro assignments within
makefiles.
- -f makefile
-
Specify a makefile to read instead of the default
`
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 private
-
This option should
not
be specified by the user.
When the
j
option is in use in a recursive build, this option is passed by a make
to child makes to allow all the make processes in the build to
cooperate to avoid overloading the system.
- -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
file<.blm Pp-style >
include statement.
The
-m
option can be used multiple times 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
file".blm Pp-style
include statements (see the
-I
option).
If a file or directory name in the
-m
argument (or the
MAKESYSPATH
environment variable) starts with the string
".../
then
make
will search for the specified file or directory named in the remaining part
of the argument string.
The search starts with the current directory of
the Makefile and then works upward towards the root of the filesystem.
If the search is successful, then the resulting directory replaces the
".../
specification in the
-m
argument.
If used, this feature allows
make
to easily search in the current source tree for customized sys.mk files
(e.g., by using
".../mk/sys.mk
as an argument).
- -n
-
Display the commands that would have been executed, but do not
actually execute them unless the target depends on the .MAKE special
source (see below).
- -N
-
Display the commands which would have been executed, but do not
actually execute any of them; useful for debugging top-level makefiles
without descending into subdirectories.
- -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
-
Do not echo any commands as they are executed.
Equivalent to specifying
`@'
before each command line in the makefile.
- -T tracefile
-
When used with the
-j
flag,
append a trace record to
tracefile
for each job started and completed.
- -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
Ns'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.
If
variable
contains a
`$'
then the value will be expanded before printing.
- -W
-
Treat any warnings during makefile parsing as errors.
- -X
-
Don't export variables passed on the command line to the environment
individually.
Variables passed on the command line are still exported
via the
MAKEFLAGS
environment variable.
This option may be useful on systems which have a small limit on the
size of command arguments.
- variable=value
-
Set the value of the variable
variable
to
value.
Normally, all values passed on the command line are also exported to
sub-makes in the environment.
The
-X
flag disables this behavior.
Variable assignments should follow options for POSIX compatibility
but no ordering is enforced.
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 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 values
`?',
`*',
`[]',
and
`{}'.
The values
`?',
`*',
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 value
`{}'
need not necessarily be used to describe existing files.
Expansion is in directory order, not alphabetically as done in the shell.
SHELL COMMANDS
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 characters of the command line are any combination of
`@',
`+',
or
`-',
the command is treated specially.
A
`@'
causes the command not to be echoed before it is executed.
A
`+'
causes the command to be executed even when
-n
is given.
This is similar to the effect of the .MAKE special source,
except that the effect can be limited to a single line of a script.
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 tradition,
consist of all upper-case letters.
Variable assignment modifiers
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.
NOTE:
References to undefined variables are
not
expanded.
This can cause problems when variable modifiers are used.
- !=
-
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 white-space 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.
Variable classes
The four different classes of variables (in order of increasing precedence)
are:
- Environment variables
-
Variables defined as part of
Ns'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.
- .IMPSRC
-
In suffix-transformation rules, the name/path of the source from which the
target is to be transformed (the
``implied''
source); also known as
`<'.
It is not defined in explicit rules.
- .MEMBER
-
The name of the archive member.
- .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 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'.
Additional built-in variables
In addition,
make
sets or knows about the following variables:
- $
-
A single dollar sign
`$',
i.e.
`$$'
expands to a single dollar
sign.
- .ALLTARGETS
-
The list of all targets encountered in the Makefile.
If evaluated during
Makefile parsing, lists only those targets encountered thus far.
- .CURDIR
-
A path to the directory where
make
was executed.
Refer to the description of
`
PWD
'
for more details.
MAKE
-
The name that
make
was executed with
(argv[0]).
For compatibility
make
also sets
.MAKE
with the same value.
The preferred variable to use is the environment variable
MAKE
because it is more compatible with other versions of
make
and cannot be confused with the special target with the same name.
- .MAKE.EXPORTED
-
The list of variables exported by
.
- .MAKE.MAKEFILES
-
The list of makefiles read by
,
which is useful for tracking dependencies.
Each makefile is recorded only once, regardless of the number of times read.
- .MAKE.PID
-
The process-id of
.
- .MAKE.PPID
-
The parent process-id of
.
- .MAKE.JOB.PREFIX
-
If
make
is run with
j
then output for each target is prefixed with a token
`--- target ---'
the first part of which can be controlled via
.MAKE.JOB.PREFIX.
For example:
.MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
would produce tokens like
`---make[1234] target ---'
making it easier to track the degree of parallelism being achieved.
MAKEFLAGS
-
The environment variable
`
MAKEFLAGS
'
may contain anything that
may be specified on
Ns's
command line.
Anything specified on
Ns's
command line is appended to the
`
MAKEFLAGS
'
variable which is then
entered into the environment for all programs which
make
executes.
- .MAKEOVERRIDES
-
This variable is used to record the names of variables assigned to
on the command line, so that they may be exported as part of
`
MAKEFLAGS
'.
This behaviour can be disabled by assigning an empty value to
`.MAKEOVERRIDES'
within a makefile.
Extra variables can be exported from a makefile
by appending their names to
`.MAKEOVERRIDES'.
`
MAKEFLAGS
'
is re-exported whenever
`.MAKEOVERRIDES'
is modified.
- MAKE_PRINT_VAR_ON_ERROR
-
When
make
stops due to an error, it prints its name and the value of
`.CURDIR'
as well as the value of any variables named in
`MAKE_PRINT_VAR_ON_ERROR'.
- .newline
-
This variable is simply assigned a newline character as its value.
This allows expansions using the
:@
modifier to put a newline between
iterations of the loop rather than a space.
For example, the printing of
`MAKE_PRINT_VAR_ON_ERROR'
could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
- .OBJDIR
-
A path to the directory where the targets are built.
Its value is determined by trying to
chdir(2)
to the following directories in order and using the first match:
-
${MAKEOBJDIRPREFIX}${.CURDIR}
(Only if
`
MAKEOBJDIRPREFIX
'
is set in the environment or on the command line.)
-
${MAKEOBJDIR}
(Only if
`
MAKEOBJDIR
'
is set in the environment or on the command line.)
-
${.CURDIR}
/obj.
${MACHINE}
-
${.CURDIR}
/obj
-
/usr/obj/
${.CURDIR}
-
${.CURDIR}
Variable expansion is performed on the value before it's used,
so expressions such as
${.CURDIR:C,^/usr/src,/var/obj,}
may be used.
`.OBJDIR'
may be modified in the makefile as a global variable.
In all cases,
make
will
chdir(2)
to
`.OBJDIR'
and set
`
PWD
'
to that directory before executing any targets.
- .PARSEDIR
-
A path to the directory of the current
`
Makefile
'
being parsed.
- .PARSEFILE
-
The basename of the current
`
Makefile
'
being parsed.
This variable and
`.PARSEDIR'
are both set only while the
`
Makefiles
'
are being parsed.
- .PATH
-
A variable that represents the list of directories that
make
will search for files.
The search list should be updated using the target
`.PATH'
rather than the variable.
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.
This behaviour is disabled if
`
MAKEOBJDIRPREFIX
'
is set or
`
MAKEOBJDIR
'
contains a variable transform.
`
PWD
'
is set to the value of
`.OBJDIR'
for all programs which
make
executes.
VPATH
-
Colon-separated
(``:'')
lists of directories that
make
will search for files.
The variable is supported for compatibility with old make programs only,
use
`.PATH'
instead.
Variable modifiers
Variable expansion may be modified to select or modify each word of the
variable (where a
``word''
is white-space delimited sequence of characters).
The general format of a variable expansion is as follows:
${variable[:modifier[:...]]}
Each modifier begins with a colon,
which may be escaped with a backslash
(`\').
A set of modifiers can be specified via a variable, as follows:
modifier_variable=modifier[:...]
${variable:${modifier_variable}[:...]}
In this case the first modifier in the modifier_variable does not
start with a colon, since that must appear in the referencing
variable.
If any of the modifiers in the modifier_variable contain a dollar sign
(`$'),
these must be doubled to avoid early expansion.
The supported modifiers are:
- :E
-
Replaces each word in the variable with its suffix.
- :H
-
Replaces each word in the variable with everything but the last component.
- :Mpattern
-
Select only those words that match
pattern.
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
pattern.
- :O
-
Order every word in variable alphabetically.
To sort words in
reverse order use the
`:O:[-1..1]'
combination of modifiers.
- :Ox
-
Randomize words in variable.
The results will be different each time you are referring to the
modified variable; use the assignment with expansion
(`:=')
to prevent such behaviour.
For example,
-
LIST= uno due tre quattro
RANDOM_LIST= ${LIST:Ox}
STATIC_RANDOM_LIST:= ${LIST:Ox}
all:
@echo "${RANDOM_LIST}"
@echo "${RANDOM_LIST}"
@echo "${STATIC_RANDOM_LIST}"
@echo "${STATIC_RANDOM_LIST}"
may produce output similar to:
-
quattro due tre uno
tre due quattro uno
due uno quattro tre
due uno quattro tre
- :Q
-
Quotes every shell meta-character in the variable, so that it can be passed
safely through recursive invocations of
.
- :R
-
Replaces each word in the variable with everything but its suffix.
- :tl
-
Converts variable to lower-case letters.
- :tsc
-
Words in the variable are normally separated by a space on expansion.
This modifier sets the separator to the character
c.
If
c
is omitted, then no separator is used.
- :tu
-
Converts variable to upper-case letters.
- :tW
-
Causes the value to be treated as a single word
(possibly containing embedded white space).
See also
`:[*]'.
- :tw
-
Causes the value to be treated as a sequence of
words delimited by white space.
See also
`:[@]'.
- :S / old_string Xo
-
/ new_string
/[ 1gW]
Modify the first occurrence of
old_string
in the variable's value, replacing it with
new_string.
If a
`g'
is appended to the last slash of the pattern, all occurrences
in each word are replaced.
If a
`1'
is appended to the last slash of the pattern, only the first word
is affected.
If a
`W'
is appended to the last slash of the pattern,
then the value is treated as a single word
(possibly containing embedded white space).
If
old_string
begins with a caret
(`^'),
old_string
is anchored at the beginning of each word.
If
old_string
ends with a dollar sign
(`$'),
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 Xo
-
/ replacement
/[ 1gW]
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))
string
pattern
and an
ed(1)-style
string
replacement.
Normally, the first occurrence of the pattern
pattern
in each word of the value is substituted with
replacement.
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
pattern
as occur in the word or words it is found in; the
`W'
modifier causes the value to be treated as a single word
(possibly containing embedded white space).
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.
- :u
-
Remove adjacent duplicate words (like
uniq(1)).
- :? true_string : false_string
-
If the variable (actually an expression; see below)
evaluates to true, return as its value the
true_string,
otherwise return the
false_string.
The expression parser needs careful feeding to avoid surprises.
For example the following all do what one might expect,
${"${NUMBERS:M42}":?match:no}
${${NUMBER:U0}
>
0:?set:zero}
${empty(NUMBER):?empty:set}
The first case expands to
`match'
if
NUMBERS
contains the value 42 (the quotes are important).
The second expands to
`zero'
unless
NUMBER
is set to a value greater than 0.
The last case expands to
`empty'
or
`set'
depending on whether
NUMBER
is empty.
In this example, use of
`{}'
rather than
`()'
is important to avoid the parser getting confused.
By contrast, the following examples will
not
behave as expected.
${"1
<
0":?always:no}
${NUMBERS:M42:?always:no}
in both cases the expansion will always be
`always'.
- :old_string=new_string
-
This is the
AT&T
System V UNIX
style variable substitution.
It must be the last modifier specified.
If
old_string
or
new_string
do not contain the pattern matching character
%
then it is assumed that they are
anchored at the end of each word, so only suffixes or entire
words may be replaced.
Otherwise
%
is the substring of
old_string
to be replaced in
new_string.
Variable expansion occurs in the normal fashion inside both
old_string
and
new_string
with the single exception that a backslash is used to prevent the
expansion of a dollar sign
(`$'),
not a preceding dollar sign as is usual.
- :@ temp @ Xo
-
string @
This is the loop expansion mechanism from the OSF Development
Environment (ODE) make.
Unlike
.for
loops expansion occurs at the time of
reference.
Assign
temp
to each word in the variable and evaluate
string.
The ODE convention is that
temp
should start and end with a period.
For example.
${LINKS:@.LINK.@${LN}
${TARGET}
${.LINK.}@}
- :Unewval
-
If the variable is undefined
newval
is the value.
If the variable is defined, the existing value is returned.
This is another ODE make feature.
It is handy for setting per-target CFLAGS for instance:
${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
If a value is only required if the variable is undefined, use:
${VAR:D:Unewval}
- :Dnewval
-
If the variable is defined
newval
is the value.
- :L
-
The name of the variable is the value.
- :P
-
The path of the node which has the same name as the variable
is the value.
If no such node exists or its path is null, then the
name of the variable is used.
- :! cmd !
-
The output of running
cmd
is the value.
- :sh
-
If the variable is non-empty it is run as a command and the output
becomes the new value.
- ::=str
-
The variable is assigned the value
str
after substitution.
This modifier and its variations are useful in
obscure situations such as wanting to apply modifiers to
.for
loop iteration variables which won't work due to the way
.for
loops are implemented.
These assignment modifiers always expand to
nothing, so if appearing in a rule line by themselves should be
preceded with something to keep
make
happy.
As in:
use_foo: .USE
.for i in ${.TARGET} ${.TARGET:R}.gz
@: ${t::=$i}
@echo t:R:T=${t:R:T}
.endfor
The
`::'
helps avoid false matches with the
AT&T
System V UNIX
style
:=
modifier and since substitution always occurs the
::=
form is vaguely appropriate.
- ::?=str
-
As for
::=
but only if the variable does not already have a value.
- ::+=str
-
Append
str
to the variable.
- ::!=cmd
-
Assign the output of
cmd
to the variable.
- :[range]
-
Selects one or more words from the value,
or performs other operations related to the way in which the
value is divided into words.
Ordinarily, a value is treated as a sequence of words
delimited by white space.
Some modifiers suppress this behaviour,
causing a value to be treated as a single word
(possibly containing embedded white space).
An empty value, or a value that consists entirely of white-space,
is treated as a single word.
For the purposes of the
`:[]'
modifier, the words are indexed both forwards using positive integers
(where index 1 represents the first word),
and backwards using negative integers
(where index -1 represents the last word).
The
range
is subjected to variable expansion, and the expanded result is
then interpreted as follows:
- index
-
Selects a single word from the value.
- start..end
-
Selects all words from
start
to
end,
inclusive.
For example,
`:[2..-1]'
selects all words from the second word to the last word.
If
start
is greater than
end,
then the words are output in reverse order.
For example,
`:[-1..1]'
selects all the words from last to first.
- *
-
Causes subsequent modifiers to treat the value as a single word
(possibly containing embedded white space).
Analogous to the effect of
"$*"
in Bourne shell.
- 0
-
Means the same as
`:[*]'.
- @
-
Causes subsequent modifiers to treat the value as a sequence of words
delimited by white space.
Analogous to the effect of
"$@"
in Bourne shell.
- #
-
Returns the number of words in the value.
INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
Makefile inclusion, conditional structures and for loops reminiscent
of the C programming language are provided in
.
All such structures are identified by a line beginning with a single
dot
(`.')
character.
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.
For compatibility with other versions of
make
`include file ...'
is also accepted.
If the include statement is written as
.-include
or as
.sinclude
then errors locating and/or opening include files are ignored.
Conditional expressions are also preceded by a single dot as the first
character of a line.
The possible conditionals are as follows:
- .export variable
-
Export the specified global variable.
If no variable is provided, all globals are exported
except for internal variables (those that start with
`.'
).
This is not affected by the
-X
flag, so should be used with caution.
Appending a variable name to
.MAKE.EXPORTED
is equivalent to exporting a variable.
- .undef variable
-
Un-define the specified global variable.
Only global variables may be un-defined.
- Xo
-
.if
![.blm Ppexpression]
[operator expression ...]
Test the value of an expression.
- Xo
-
.ifdef
![.blm Ppvariable]
[operator variable ...]
Test the value of a variable.
- Xo
-
.ifndef
![.blm Ppvariable]
[operator variable ...]
Test the value of a variable.
- Xo
-
.ifmake
![.blm Pptarget]
[operator target ...]
Test the target being built.
- Xo
-
.ifnmake
![.blm Pptarget]
[operator target ...]
Test the target being built.
- .else
-
Reverse the sense of the last conditional.
- Xo
-
.elif
![.blm Ppexpression]
[operator expression ...]
A combination of
`.else'
followed by
`.if'.
- Xo
-
.elifdef
![.blm Ppvariable]
[operator variable ...]
A combination of
`.else'
followed by
`.ifdef'.
- Xo
-
.elifndef
![.blm Ppvariable]
[operator variable ...]
A combination of
`.else'
followed by
`.ifndef'.
- Xo
-
.elifmake
![.blm Pptarget]
[operator target ...]
A combination of
`.else'
followed by
`.ifmake'.
- Xo
-
.elifnmake
![.blm Pptarget]
[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
Ns'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.
- commands
-
Takes a target name as an argument and evaluates to true if the target
has been defined and has commands associated with it.
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 or an empty string in the case
of a string comparison.
When
make
is evaluating one of these conditional expression, 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:
- Xo
-
.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 taken and assigned to each
variable,
in order, and these
variables
are substituted into the
make-rules
inside the body of the for loop.
The number of words must come out even; that is, if there are three
iteration variables, the number of words provided must be a multiple
of three.
Comments begin with a hash
(`#')
character, anywhere but in a shell
command line, and continue to the end of an unescaped new line.
SPECIAL SOURCES (ATTRIBUTES)
- .EXEC
-
Target is never out of date, but always execute commands anyway.
- .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-to-date.
- .MAKE
-
Execute the commands associated with this target even if the
-n
or
-t
options were specified.
Normally used to mark recursive
Ns's.
- .NOPATH
-
Do not search for the target in the directories specified by
.PATH.
- .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.
- .PHONY
-
The target does not
correspond to an actual file; it is always considered to be out of date,
and will not be created with the
-t
option.
- .PRECIOUS
-
When
make
is interrupted, it normally removes any partially made targets.
This source prevents the target from being removed.
- .RECURSIVE
-
Synonym for
.MAKE.
- .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
Ns'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.
- .USEBEFORE
-
Exactly like
.USE,
but prepend the
.USEBEFORE
target commands to the target.
- .WAIT
-
If
.WAIT
appears in a dependency line, the sources that precede it are
made before the sources that succeed it in the line.
Since the dependents of files are not made until the file itself
could be made, this also stops the dependents being built unless they
are needed for another branch of the dependency tree.
So given:
x: a .WAIT b
echo x
a:
echo a
b: b1
echo b
b1:
echo b1
the output is always
`a',
`b1',
`b',
`x'.
The ordering imposed by
.WAIT
is only relevant for parallel makes.
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 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.
- .INTERRUPT
-
If
make
is interrupted, the commands for this target will be executed.
- .MAIN
-
If no target is specified when
make
is invoked, this target will be built.
- .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.
- .NOPATH
-
Apply the
.NOPATH
attribute to any specified sources.
- .NOTPARALLEL
-
Disable parallel mode.
- .NO_PARALLEL
-
Synonym for
.NOTPARALLEL,
for compatibility with other pmake variants.
- .ORDER
-
The named targets are made in sequence.
This ordering does not add targets to the list of targets to be made.
Since the dependents of a target do not get built until the target itself
could be built, unless
`a'
is built by another part of the dependency graph,
the following is a dependency loop:
.ORDER a b
b: a
The ordering imposed by
.ORDER
is only relevant for parallel makes.
- .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.
If the source is the special
.DOTLAST
target, then the current working
directory is searched last.
- .PHONY
-
Apply the
.PHONY
attribute to any specified sources.
- .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.
- .SHELL
-
Sets the shell that
make
will use to execute commands.
The sources are a set of
field=value
pairs.
- name
-
This is the minimal specification, used to select one of the builtin
shell specs;
sh,
ksh,
and
csh.
- path
-
Specifies the path to the shell.
- hasErrCtl
-
Indicates whether the shell supports exit on error.
- check
-
The command to turn on error checking.
- ignore
-
The command to disable error checking.
- echo
-
The command to turn on echoing of commands executed.
- quiet
-
The command to turn off echoing of commands executed.
- filter
-
The output to filter after issuing the
quiet
command.
It is typically identical to
quiet.
- errFlag
-
The flag to pass the shell to enable error checking.
- echoFlag
-
The flag to pass the shell to enable command echoing.
- newline
-
The string literal to pass the shell that results in a single newline
character when used outside of any quoting characters.
Example:
.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \
check="set -e" ignore="set +e" \
echo="set -v" quiet="set +v" filter="set +v" \
echoFlag=v errFlag=e newline="'\n'"
- .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
.
If no sources are specified, any previously specified suffixes are deleted.
It allows the creation of suffix-transformation rules.
Example:
.SUFFIXES: .o
.c.o:
cc -o ${.TARGET} -c ${.IMPSRC}
ENVIRONMENT
make
uses the following environment variables, if they exist:
MACHINE
,
MACHINE_ARCH
,
MAKE
,
MAKEFLAGS
,
MAKEOBJDIR
,
MAKEOBJDIRPREFIX
,
MAKESYSPATH
,
and
PWD
.
MAKEOBJDIRPREFIX
and
MAKEOBJDIR
may only be set in the environment or on the command line to
make
and not as makefile variables;
see the description of
`.OBJDIR'
for more details.
FILES
- .depend
-
list of dependencies
- Makefile
-
list of dependencies
- makefile
-
list of dependencies
- sys.mk
-
system makefile
- /usr/share/mk
-
system makefile directory
COMPATIBILITY
The basic make syntax is compatible between different versions of make,
however the special variables, variable modifiers and conditionals are not.
The way that parallel makes are scheduled changed in
NetBSD4.0
so that .ORDER and .WAIT apply recursively to the dependant nodes.
The algorithms used may change again in the future.
SEE ALSO
mkdep(1)
HISTORY
A
make
command appeared in
Version 7 AT&T UNIX
.