term% cat index.txt MAKE(1) General Commands Manual MAKE(1)
NAME
make - maintain collections of programs
SYNOPSIS
make [ -f makefile ] [ option ] ... [ name ] ...
DESCRIPTION
Make executes commands in makefile to update the target names (usually
programs). If no target is specified, the targets of the first rule in
makefile are updated. If no -f option is present, `makefile' and
`Makefile' are tried in order. If makefile is `-', the standard input
is taken. More than one -f option may appear.
Make updates a target if it depends on prerequisite files that have
been modified since the target was last modified, or if the target does
not exist. The prerequisites are updated before the target.
The makefile comprises a sequence of rules and macro definitions. The
first line of a rule is a blank-separated list of targets, then a sin‐
gle or double colon, then a list of prerequisite files terminated by
semicolon or newline. Text following a semicolon, and all following
lines that begin with a tab, are shell commands to be executed to up‐
date the target.
If a name appears as target in more than one single-colon rule, it de‐
pends on all of the prerequisites of those rules, but only one command
sequence may be specified among the rules. A target in a double-colon
rule is updated by the following command sequence only if it is out of
date with respect to the prerequisites of that rule.
Two special forms of name are recognized. A name like a(b) means the
file named b stored in the archive named a. A name like a((b)) means
the file stored in archive a and containing the entry point b.
Sharp and newline surround comments.
In this makefile `pgm' depends on two files `a.o' and `b.o', and they
in turn depend on `.c' files and a common file `ab.h':
pgm: a.o b.o
cc a.o b.o -lplot -o pgm
a.o: ab.h a.c
cc -c a.c
b.o: ab.h b.c
cc -c b.c
Makefile lines of the form
string1 = string2
are macro definitions. Subsequent appearances of $(string1) are re‐
placed by string2. If string1 is a single character, the parentheses
are optional. Each entry in the environment (see sh(1)) of the make
command is taken as a macro definition, as are command arguments with
embedded equal signs.
A target containing a single `%' introduces a pattern rule, which con‐
trols the making of names that do not occur explicitly as targets. The
`%' matches an arbitrary string called the stem: A%B matches any string
that begins with A and ends with B. A `%' in a prerequisite name
stands for the stem; and the special macro `$%' stands for the stem in
the construction commands. A name that has no explicit rule is matched
against the target of each pattern rule. The first pattern rule for
which the prerequisites exist specifies further dependencies.
This pattern rule maintains an object library where all the C source
files share a common include file `defs.h'. The macro `CFLAGS' sets
compiler options.
arch.a(%.o) : %.c defs.h
cc $(CFLAGS) -c $%.c
ar r arch.a $%.o
rm $%.o
A set of default pattern rules is built in, and effectively follows the
user's list of rules. Assuming these rules, which tell, among other
things, how to make `.o' files from `.c' files, the first example be‐
comes:
pgm: a.o b.o
cc a.o b.o -lplot -o pgm
a.o b.o: ab.h
Here, greatly simplified, is a sample of the built-in rules:
CC = cc
%.o: %.c
$(CC) $(CFLAGS) -c $%.c
%.o: %.f
f77 $(FFLAGS) -c $%.f
% : %.c
$(CC) $(CFLAGS) -o $% $%.c
The first rule says that a name ending in `.o' could be made if a
matching name ending in `.c' were present. The second states a similar
rule for files ending in `.f'. The third says that an arbitrary name
can be made by compiling a file with that name suffixed by `.c'.
Macros make the builtin pattern rules flexible: CC names the particular
C compiler, CFLAGS gives cc(1) options, FFLAGS for f77(1), LFLAGS for
lex(1), YFLAGS for yacc(1), and PFLAGS for pascal(1).
An older, now disparaged, means of specifying default rules is based
only on suffixes. Prerequisites are inferred according to selected
suffixes listed as the `prerequisites' for the special name `.SUF‐
FIXES'; multiple lists accumulate; an empty list clears what came be‐
fore.
The rule to create a file with suffix s2 that depends on a similarly
named file with suffix s1 is specified as an entry for the `target'
s1s2. Order is significant; the first possible name for which both a
file and a rule exist is inferred. An old style rule for making opti‐
mized `.o' files from `.c' files is
.c.o: ; cc -c -O -o $@ $*.c
The following two macros are defined for use in any rule:
$($@) full name of target
$($/) target name beginning at the last slash, if any
A number of other special macros are defined automatically in rules in‐
voked by one of the implicit mechanisms:
$* target name with suffix deleted
$@ full target name
$< list of prerequisites in an implicit rule
$? list of prerequisites that are out of date
$^ list of all prerequisites
The following are included for consistency with System V:
$(@D) directory part of $@ (up to last slash)
$(@F) file name part of $@ (after last slash)
$(*D) directory part of $* (up to last slash)
$(*F) file name part of $* (after last slash)
$(<D) directory part of $< (up to last slash)
$(<F) file name part of $< (after last slash)
Command lines are executed one at a time, each by its own shell. A
line is printed when it is executed unless the special target `.SILENT'
is in the makefile, or the first character of the command is `@'.
Commands returning nonzero status (see intro(1)) cause make to termi‐
nate unless the special target `.IGNORE' is in the makefile or the com‐
mand begins with <tab><hyphen>.
Interrupt and quit cause the target to be deleted unless the target de‐
pends on the special name `.PRECIOUS'.
Make includes a rudimentary parallel processing ability. If the sepa‐
ration string is `:&' or `::&', make can run the command sequences to
create the prerequisites simultaneously. If two names are separated by
an ampersand on the right side of a colon, those two may be created in
parallel.
Other options:
-i Equivalent to the special entry `.IGNORE:'.
-k When a command returns nonzero status, abandon work on the cur‐
rent entry, but continue on branches that do not depend on the
current entry.
-n Trace and print, but do not execute the commands needed to up‐
date the targets.
-t Touch, i.e. update the modified date of targets, without execut‐
ing any commands.
-r Equivalent to an initial special entry `.SUFFIXES:' with no
list.
-s Equivalent to the special entry `.SILENT:'.
-e Environment definitions override conflicting definitions in ar‐
guments or in makefiles. Ordinary precedence is argument over
makefile over environment.
-o Assume old style default suffix list: .SUFFIXES: .out .o .c .e
.r .f .y .l .s .p
-Pn Permit n command sequences to be done in parallel with `&'.
FILES
makefile, Makefile
SEE ALSO
sh(1), touch(1), ar(1)
S. I. Feldman Make - A Program for Maintaining Computer Programs
MAKE(1)