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MAKE (1)
NAME
make - maintain program dependencies
SYNOPSIS
make [ eiknqrstv ] [ D ] [ d ] [ f ] [ I ] [ j ] [
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 [Pa] ex-
ists, it is read for this list of specifications. If it does not
exist, the file [Pa] is read. If the file [Pa] 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
The options are as follows:
D - Define Ar variable to be 1, in the global context.
d - 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 search-
ing 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 assign-
ment.
e - Specify that environmental variables override macro as-
signments within makefiles.
f - Specify a makefile to read instead of the default [Pa]
and [Pa] If makefile is [Fl] standard input is read. Multi-
ple makefile's may be specified, and are read in the order
specified.
I - Specify a directory in which to search for makefiles and
included makefiles. The system makefile directory is au-
tomatically included as part of this list.
i - Ignore non-zero exit of shell commands in the makefile.
Equivalent to specifying [Fl] before each command line in
the makefile.
j - 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 [Ic] 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 depen-
dency 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 neces-
sarily 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 com-
mands, normally used to create the target. Each of the commands
in this script be preceded by a tab. While any target may appear
on a dependency line, only one of these dependencies may be fol-
lowed by a creation script, unless the [Ic] operator is used.
If the first or first two characters of the command line are
[Ic] and/or [Ic] the command is treated specially. A [Ic] causes
the command not to be echoed before it is executed. A [Ic]
causes any non-zero exit status of the command line to be ig-
nored.
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 as-
signing 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 sur-
rounding 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 com-
mands are expanded when the shell command is executed.
The four different classes of variables (in order of increasing
precedence) are:
variables - Variables defined as part of make environment.
variables - Variables defined in the makefile or in included
makefiles.
line - Variables defined as part of the command line.
variables - Variables that are defined specific to a certain
target. The seven local variables are as follows:
The list of all sources for this target; also known as
[Va]
The name of the archive file.
The name/path of the source from which the target is to
be transformed (the ``implied'' source); also known as
[Va]
The name of the archive member.
The list of sources for this target that were deemed
out-of-date; also known as [Va]
The file prefix of the file, containing only the file
portion, no suffix or preceding directory components;
also known as [Va]
The name of the target; also known as [Va]
The shorter forms [Va] [Va] [Va] and [Va] are permitted
for backward compatibility with historical makefiles and are
not recommended. The six variables [Va] [Va] [Va] [Va] [Va]
and [Va] are permitted for compatibility with 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 [Va] [Va] [Va]
and [Va]
In addition, make sets or knows about the following vari-
ables:
$ - A single dollar sign [$] i.e. [$$] expands to a
single dollar sign.
The name that make was executed with
A path to the directory where make was executed.
MAKEFLAGS - The environment variable [Ev] may contain
anything that may be specified on make command line.
Anything specified on make command line is appended to
the [Ev] variable which is then entered into the en-
vironment 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:
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 - Select only those words that match the rest of the
modifier. The standard shell wildcard characters [?]
and [Op] may be used. The wildcard characters may be
escaped with a backslash
N - This is identical to [Cm] 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 - 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 oc-
currences in each word are replaced. If old_pattern
begins with a carat old_pattern is anchored at the be-
ginning of each word. If old_pattern ends with a dol-
lar sign it is anchored at the end of each word. In-
side 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 ex-
ception that a backslash is used to prevent the expan-
sion 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 style variable sub-
stitution. 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] or
[.include] Variables between the angle brackets or double
quotes are expanded to form the file name. If angle brack-
ets 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 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 condition-
als are as follows:
Un-define the specified global variable. Only global
variables may be un-defined.
- [ operator ] Test the value of an expression.
- [ operator ] Test the value of an variable.
- [ operator ] Test the value of an variable.
- [ operator ] Test the the target being built.
- [ operator ] Test the target being built.
Reverse the sense of the last conditional.
- [ operator ] A combination of [Ic] followed by [Ic]
- [ operator ] A combination of [Ic] followed by [Ic]
- [ operator ] A combination of [Ic] followed by [Ic]
- [ operator ] A combination of [Ic] followed by [Ic]
- [ operator ] A combination of [Ic] followed by [Ic]
End the body of the conditional.
The operator may be any one of the following:
|| - logical OR
&& - Logical 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 opera-
tor [Ic] may be used to logically negate an entire condi-
tional. It is of higher precendence than [Ic]
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
command line or was declared the default target (either
implicitly or explicitly, see before the line contain-
ing 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
target - Takes a target name as an argument and evalu-
ates 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 [Ic]
or [Ic] operator begins with a quotation mark a string com-
parison 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 expres-
sion, 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
[Ic] or [Ic] the ``defined'' expression is applied. Simi-
larly, if the form is [Ic] or [Ic] 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 [Ic] or [Ic] 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 any errors from the commands associated with
this target, exactly as if they all were preceded by a
dash
Execute the commands associated with this target even
if the or options were specified. Normally used to
mark recursive make
Normally make selects the first target it encounters as
the default target to be built if no target was speci-
fied. This source prevents this target from being
selected.
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 ex-
ists.
When make is interrupted, it removes any partially made
targets. This source prevents the target from being
removed.
Do not echo any of the commands associated with this
target, exactly as if they all were preceded by an at
sign
Turn the target into make version of a macro. When the
target is used as a source for another target, the oth-
er target acquires the commands, sources, and attri-
butes (except for of the source. If the target already
has commands, the 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.
Any command lines attached to this target are executed
before anything else is done.
This is sort of a 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
variable of a target that inherits commands is set to
the target's own name.
Any command lines attached to this target are executed
after everything else is done.
Mark each of the sources with the attribute. If no
sources are specified, this is the equivalent of speci-
fying the option.
If make is interrupted, the commands for this target
will be executed.
If no target is specified when make is invoked, this
target will be built.
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 option will have no effect.
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 direc-
tories are deleted.
Apply the attribute to any specified sources. If no
sources are specified, the attribute is applied to
every target in the file.
Apply the attribute to any specified sources. If no
sources are specified, the attribute is applied to
every command in the file.
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: and
FILES
- list of dependencies
- list of dependencies
- list of dependencies
- system makefile
- system makefile directory
SEE ALSO
mkdep (1)
HISTORY
A Make command appeared in