MAKE(1)
NAME
make - maintain program dependencies
SYNOPSIS
make [-eiknqrstv] [-D variable] [-d flags] [-f makefile] [-I directory]
[-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 follow-
ing:
A Print all possible debugging information; equivalent to
specifying all of the debugging flags.
a Print debugging information about archive searching and
caching.
c Print debugging information about conditional evaluation.
d Print debugging information about directory searching and
caching.
g1 Print the input graph before making anything.
g2 Print the input graph after making everything, or before
exiting on error.
j Print debugging information about running multiple
shells.
m Print debugging information about making targets, includ-
ing modification dates.
s Print debugging information about suffix-transformation
rules.
t Print debugging information about target list mainte-
nance.
v Print debugging information about variable assignment.
-e Specify that 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 in-
cluded as part of this list.
-i Ignore non-zero exit of shell commands in the makefile. Equiva-
lent to specifying `-' before each command line in the makefile.
-j max_jobs
Specify the maximum number of jobs that make may have running at
any one time.
-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 sep-
arates them. The three operators are as follows:
: A target is considered out-of-date if its modification time is less
than those of any of its sources. Sources for a target accumulate
over dependency lines when this operator is used. The target is
removed if make is interrupted.
! Targets are always re-created, but not until all sources have been
examined and re-created as necessary. Sources for a target accumu-
late over dependency lines when this operator is used. The target
is removed if make is interrupted.
:: If no sources are specified, the target is always re-created. Oth-
erwise, a target is considered out-of-date if any of its sources
has been modified more recently than the target. Sources for a
target do not accumulate over dependency lines when this operator
is used. The target will not be removed if make is interrupted.
Targets and sources may contain the shell wildcard 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 ex-
isting 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, nor-
mally used to create the target. Each of the commands in this script
must be preceded by a tab. While any target may appear on a dependency
line, only one of these dependencies may be followed by a creation
script, unless the `::' operator is used.
If the first or first two characters of the command line are `@' and/or
`-', the command is treated specially. A `@' causes the command not to
be echoed before it is executed. A `-' causes any non-zero exit status
of the command line to be ignored.
VARIABLE ASSIGNMENTS
Variables in make are much like variables in the shell, and, by tradi-
tion, consist of all upper-case letters. The five operators that can be
used to assign values to variables are as follows:
= Assign the value to the variable. Any previous value is overrid-
den.
+= Append the value to the current value of the variable.
?= Assign the value to the variable if it is not already defined.
:= Assign with expansion, i.e. expand the value before assigning it
to the variable. Normally, expansion is not done until the vari-
able is referenced.
!= Expand the value and pass it to the shell for execution and as-
sign the result to the variable. Any newlines in the result are
replaced with spaces.
Any white-space before the assigned value is removed; if the value is be-
ing appended, a single space is inserted between the previous contents of
the variable and the appended value.
Variables are expanded by surrounding the variable name with either curly
braces (`{}') or parenthesis (`()') and preceding it with a dollar sign
(`$'). If the variable name contains only a single letter, the surround-
ing 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 prece-
dence) are:
Environment variables
Variables defined as part of make's environment.
Global variables
Variables defined in the makefile or in included makefiles.
Command line variables
Variables defined as part of the command line.
Local variables
Variables that are defined specific to a certain target. The
seven local variables are as follows:
.ALLSRC The list of all sources for this target; also known as
`>'.
.ARCHIVE The name of the archive file.
.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 back-
ward compatibility with historical makefiles and are not recom-
mended. The six variables `@F', `@D', `<F', `', `*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 variables:
$ A single dollar sign `$', i.e. `$$' expands to a sin-
gle 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 any-
thing 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 se-
quence of characters). The general format of a variable expan-
sion is as follows:
{variable[:modifier[:...]]}
Each modifier begins with a colon and one of the following spe-
cial 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.
Mpattern Select only those words that match the rest of the
modifier. The standard shell wildcard characters
(`*', `?', and `[]') may be used. The wildcard char-
acters 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.
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 ap-
pended to the last slash of the pattern, all occur-
rences in each word are replaced. If old_pattern be-
gins with a carat (`^'), old_pattern is anchored at
the beginning of each word. If old_pattern ends with
a dollar sign (`$'), it is anchored at the end of
each word. Inside new_string, an ampersand (`&') is
replaced by old_pattern. Any character may be used as
a delimiter for the parts of the modifier string.
The anchoring, ampersand and delimiter characters may
be escaped with a backslash (`\').
Variable expansion occurs in the normal fashion in-
side both old_string and new_string with the single
exception that a backslash is used to prevent the ex-
pansion of a dollar sign (`$') not a preceding dollar
sign as is usual.
T Replaces each word in the variable with its last com-
ponent.
old_string=new_string
This is the AT&T System V UNIX style variable substi-
tution. 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 pro-
gramming language are provided in make. All such structures are identi-
fied 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 in-
cluding 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 explic-
itly, 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 emp-
ty string.
exists Takes a file name as an argument and evaluates to true if the
file exists. The file is searched for on the system search
path (see .PATH).
target Takes a target name as an argument and evaluates to true if
the target has been defined.
Expression may also be an arithmetic or string comparison, with the left-
hand side being a variable expansion. The standard C relational opera-
tors are all supported, and the usual number/base conversion is per-
formed. 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 en-
counters a word it doesn't recognize, either the ``make'' or ``defined''
expression is applied to it, depending on the form of the conditional.
If the form is `.ifdef' or `.ifndef', the ``defined'' expression is ap-
plied. Similarly, if the form is `.ifmake' or `.ifnmake, the ``make'''
expression is applied.
If the conditional evaluates to true the parsing of the makefile contin-
ues as before. If it evaluates to false, the following lines are
skipped. In both cases this continues until a `.else' or `.endif' is
found.
COMMENTS
Comments begin with a hash (`#') character, anywhere but in a shell com-
mand line, and continue to the end of the line.
SPECIAL SOURCES
.IGNORE Ignore any errors from the commands associated with this tar-
get, exactly as if they all were preceded by a dash (`-').
.MAKE Execute the commands associated with this target even if the
-n or -t options were specified. Normally used to mark re-
cursive make's.
.NOTMAIN Normally make selects the first target it encounters as the
default target to be built if no target was specified. This
source prevents this target from being selected.
.OPTIONAL If a target is marked with this attribute and make can't fig-
ure out how to create it, it will ignore this fact and assume
the file isn't needed or already exists.
.PRECIOUS When make is interrupted, it removes any partially made tar-
gets. This source prevents the target from being removed.
.SILENT Do not echo any of the commands associated with this target,
exactly as if they all were preceded by an at sign (`@').
.USE Turn the target into make's. version of a macro. When the
target is used as a source for another target, the other tar-
get acquires the commands, sources, and attributes (except
for .USE) of the source. If the target already has commands,
the .USE target's commands are appended to them.
SPECIAL TARGETS
Special targets may not be included with other targets, i.e. they must be
the only target specified.
.BEGIN Any command lines attached to this target are executed before
anything else is done.
.DEFAULT This is sort of a .USE rule for any target (that was used on-
ly as a source) that make can't figure out any other way to
create. Only the shell script is used. The .IMPSRC variable
of a target that inherits .DEFAULT's commands is set to the
target's own name.
.END Any command lines attached to this target are executed after
everything else is done.
.IGNORE Mark each of the sources with the .IGNORE attribute. If no
sources are specified, this is the equivalent of specifying
the -i option.
.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
/usr/share/mk system makefile directory
SEE ALSO
mkdep(1)
HISTORY
A Make command appeared in Version 7 AT&T UNIX.