MAKE
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NAME
make
- maintain program dependencies
SYNOPSIS
make
[-eiknqrstv
]
[-D variable
]
[-d flags
]
[-f makefile
]
[-I directory
]
-words
[-j max_jobs
]
[variable=value
]
[target ...
]
DESCRIPTION
Make
is a program designed to simplify the maintenance of other programs.
Its input is a list of specifications as to the files upon which programs
and other files depend.
If the file
`makefile
'
exists, it is read for this list of specifications.
If it does not exist, the file
`Makefile
'
is read.
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 - A Tutorial" .
The options are as follows:
- -D variable
-
Define Ar variable
to be 1, in the global context.
- -d flags
-
Turn on debugging, and specify which portions of
make
are to print debugging information.
Flags
is one or more of the 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.
- g1
-
Print the input graph before making anything.
- g2
-
Print the input graph after making everything, or before exiting
on error.
- j
-
Print debugging information about running multiple shells.
- m
-
Print debugging information about making targets, 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
-
Specify that environmental 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 makefile's 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 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.
- -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 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
-
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.
- variable=value
-
Set the value of the variable
variable
to
value
There are six different types of lines in a makefile: file dependency
specifications, shell commands, variable assignments, include statements,
conditional directives, 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 or first two characters of the command line are
`@
'
and/or
`-
'
,
the command is treated specially.
A
`@
'
causes the command not to be echoed before it is executed.
A
`-
'
causes any non-zero exit status of the command line to be ignored.
VARIABLE ASSIGNMENTS
Variables in make are much like variables in the shell, and, by 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 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 parenthesis
(`()'
)
and preceding it with
a dollar sign
(`$'
)
If the variable name contains only a single letter, the surrounding
braces or parenthesis 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.
- .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.
- .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
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 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.
- MAKEFLAGS
-
The environment variable
`MAKEFLAGS
'
may contain anything that
may be specified on
make 's
command line.
Anything specified on
make 's
command line is appended to the
`MAKEFLAGS
'
variable which is then
entered into the environment for all programs which
make
executes.
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 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.
- M pattern
-
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
(`\'
)
- N pattern
-
This is identical to
`M
'
,
but selects all words which do not match
the rest of the modifier.
- R
-
Replaces each word in the variable with everything but its suffix.
- S / old_pattern
/ new_pattern
/ [g
]
-
- Modify the first occurrence of
old_pattern
in each word to be replaced with
new_pattern
If a
`g'
is appended to the last slash of the pattern, all occurrences
in each word are replaced.
If
old_pattern
begins with a carat
(`^'
)
old_pattern
is anchored at the beginning of each word.
If
old_pattern
ends with a dollar sign
(`$'
)
it is anchored at the end of each word.
Inside
new_string
an ampersand
(`&'
)
is replaced by
old_pattern
Any character may be used as a delimiter for the parts of the modifier
string.
The anchoring, ampersand and delimiter characters may be escaped with a
backslash
(`\'
)
Variable expansion occurs in the normal fashion inside both
old_string
and
new_string
with the single exception that a backslash is used to prevent the expansion
of a dollar sign
(`$'
)
not a preceding dollar sign as is usual.
- T
-
Replaces each word in the variable with its last component.
- old_string=new_string
-
This is the
AT&T System
V
style variable substitution.
It must be the last modifier specified.
Old_string
is anchored at the end of each word, so only suffixes or entire
words may be replaced.
INCLUDE STATEMENTS AND CONDITIONALS
Makefile inclusion and conditional structures reminiscent of the C
programming language are provided in
make
All such structures are identified by a line beginning with a single
dot
(`.'
)
character.
Files are included with either
`.include'
<file>
or
`.include'
file .
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
chraracter 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 an variable.
-
.ifndef
[! variable
]
[operator variable ...
]
-
- Test the value of an variable.
-
.ifmake
[! target
]
[operator target ...
]
-
- Test the 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.
Parenthesis 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 precendence 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 evalutes 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, with the left-hand side
being a variable expansion.
The standard C relational operators are all supported, and the usual
number/base conversion is performed.
Note, octal numbers are not supported.
If the righthand value of a
`==
'
or
`!=
'
operator begins with a
quotation mark
(`'
)
a string comparison is done between the expanded
variable and the text between the quotation marks.
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 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.
COMMENTS
Comments begin with a hash
(`#'
)
character, anywhere but in a shell
command line, and continue to the end of the line.
SPECIAL SOURCES
- .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.
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.
- .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.
- .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 specifies suffices are deleted.
ENVIRONMENT
Make
utilizes the following environment variables, if they exist:
MAKE
MAKEFLAGS
and
MAKEOBJDIR
FILES
- .depend
-
list of dependencies
- Makefile
-
list of dependencies
- makefile
-
list of dependencies
- sys.mk
-
system makefile
- /bsd/share/mk
-
system makefile directory
SEE ALSO
mkdep(1)
HISTORY
A
Make
command appeared in
AT&T System
v7 .
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- FILE DEPENDENCY SPECIFICATIONS
-
- SHELL COMMANDS
-
- VARIABLE ASSIGNMENTS
-
- INCLUDE STATEMENTS AND CONDITIONALS
-
- COMMENTS
-
- SPECIAL SOURCES
-
- SPECIAL TARGETS
-
- ENVIRONMENT
-
- FILES
-
- SEE ALSO
-
- HISTORY
-
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Time: 08:43:25 GMT, September 19, 2022