sysV-make(1)
NAME
sysV-make - maintain, update, and regenerate groups of pro-
grams
SYNOPSIS
/usr/lib/svr4.make [-f makefile] [-eiknpqrst] [names]
DESCRIPTION
This is the "vanilla" System V version of make. If the
environment variable USE_SVR4_MAKE is set, then the command
make will invoke this version of make. (See also the
ENVIRONMENT section.)
make allows the programmer to maintain, update, and regen-
erate groups of computer programs. make executes commands in
makefile to update one or more target names (names are typi-
cally programs). If the -f option is not present, then
makefile, Makefile, and the Source Code Control System
(SCCS) files s.makefile and s.Makefile are tried in order.
If makefile is `-' the standard input is taken. More than
one -f makefile argument pair may appear.
make updates a target only if its dependents are newer than
the target. All prerequisite files of a target are added
recursively to the list of targets. Missing files are deemed
to be outdated.
The following list of four directives can be included in
makefile to extend the options provided by make. They are
used in makefile as if they were targets:
.DEFAULT:
If a file must be made but there are no explicit com-
mands or relevant built-in rules, the commands associ-
ated with the name .DEFAULT are used if it exists.
.IGNORE:
Same effect as the -i option.
.PRECIOUS:
Dependents of the .PRECIOUS entry will not be removed
when quit or interrupt are hit.
.SILENT:
Same effect as the -s option.
Options
The options for make are listed below:
- e Environment variables override assignments within
makefiles.
-f makefile
Description filename (makefile is assumed to be the
name of a description file).
-i Ignore error codes returned by invoked commands.
-k Abandon work on the current entry if it fails, but
continue on other branches that do not depend on that
entry.
-n No execute mode. Print commands, but do not execute
them. Even command lines beginning with an `@' are
printed.
-p Print out the complete set of macro definitions and
target descriptions.
-q Question. make returns a zero or non-zero status code
depending on whether or not the target file has been
updated.
-r Do not use the built-in rules.
-s Silent mode. Do not print command lines before exe-
cuting.
-t Touch the target files (causing them to be updated)
rather than issue the usual commands.
Creating the makefile
The makefile invoked with the -f option is a carefully
structured file of explicit instructions for updating and
regenerating programs, and contains a sequence of entries
that specify dependencies. The first line of an entry is a
blank-separated, non-null list of targets, then a `:', then
a (possibly null) list of prerequisite files or dependen-
cies. Text following a `;' and all following lines that
begin with a tab are shell commands to be executed to update
the target. The first non-empty line that does not begin
with a tab or `#' begins a new dependency or macro defini-
tion. Shell commands may be continued across lines with a
backslash-new-line (\-NEWLINE) sequence. Everything printed
by make (except the initial TAB) is passed directly to the
shell as is. Thus,
echo a\
b
will produce
ab
exactly the same as the shell would.
Number-sign (#) and NEWLINE surround comments including con-
tained `\-NEWLINE' sequences.
The following makefile says that pgm depends on two files
a.o and b.o, and that they in turn depend on their
corresponding source files (a.c and b.c) and a common file
incl.h:
pgm: a.o b.o
cc a.o b.o -o pgm
a.o: incl.h a.c
cc -c a.c
b.o: incl.h b.c
cc -c b.c
Command lines are executed one at a time, each by its own
shell. The SHELL environment variable can be used to specify
which shell make should use to execute commands. The default
is /usr/bin/sh. The first one or two characters in a command
can be the following: `@', `-', `@-', or `-@'. If `@' is
present, printing of the command is suppressed. If `-' is
present, make ignores an error. A line is printed when it
is executed unless the -s option is present, or the entry
.SILENT: is included in makefile, or unless the initial
character sequence contains a @. The -n option specifies
printing without execution; however, if the command line has
the string $(MAKE) in it, the line is always executed (see
the discussion of the MAKEFLAGS macro in the make Environ-
ment sub-section below). The -t (touch) option updates the
modified date of a file without executing any commands.
Commands returning non-zero status normally terminate make.
If the -i option is present, if the entry .IGNORE: is
included in makefile, or if the initial character sequence
of the command contains `-', the error is ignored. If the -k
option is present, work is abandoned on the current entry,
but continues on other branches that do not depend on that
entry.
Interrupt and quit cause the target to be deleted unless the
target is a dependent of the directive .PRECIOUS.
make Environment
The environment is read by make. All variables are assumed
to be macro definitions and are processed as such. The
environment variables are processed before any makefile and
after the internal rules; thus, macro assignments in a
makefile override environment variables. The -e option
causes the environment to override the macro assignments in
a makefile. Suffixes and their associated rules in the
makefile will override any identical suffixes in the built-
in rules.
The MAKEFLAGS environment variable is processed by make as
containing any legal input option (except -f and -p) defined
for the command line. Further, upon invocation, make
"invents" the variable if it is not in the environment, puts
the current options into it, and passes it on to invocations
of commands. Thus, MAKEFLAGS always contains the current
input options. This feature proves very useful for "super-
makes". In fact, as noted above, when the -n option is
used, the command $(MAKE) is executed anyway; hence, one can
perform a make -n recursively on a whole software system to
see what would have been executed. This result is possible
because the -n is put in MAKEFLAGS and passed to further
invocations of $(MAKE). This usage is one way of debugging
all of the makefiles for a software project without actually
doing anything.
Include Files
If the string include appears as the first seven letters of
a line in a makefile, and is followed by a blank or a tab,
the rest of the line is assumed to be a filename and will be
read by the current invocation, after substituting for any
macros.
Macros
Entries of the form string1 = string2 are macro definitions.
string2 is defined as all characters up to a comment charac-
ter or an unescaped NEWLINE. Subsequent appearances of
$(string1[:subst1=[subst2]]) are replaced by string2. The
parentheses are optional if a single-character macro name is
used and there is no substitute sequence. The optional
:subst1=subst2 is a substitute sequence. If it is speci-
fied, all non-overlapping occurrences of subst1 in the named
macro are replaced by subst2. Strings (for the purposes of
this type of substitution) are delimited by BLANKs, TABs,
NEWLINE characters, and beginnings of lines. An example of
the use of the substitute sequence is shown in the Libraries
sub-section below.
Internal Macros
There are five internally maintained macros that are useful
for writing rules for building targets.
$* The macro $* stands for the filename part of the
current dependent with the suffix deleted. It is
evaluated only for inference rules.
$@ The $@ macro stands for the full target name of the
current target. It is evaluated only for explicitly
named dependencies.
$< The $< macro is only evaluated for inference rules or
the .DEFAULT rule. It is the module that is outdated
with respect to the target (the "manufactured" depen-
dent file name). Thus, in the .c.o rule, the $< macro
would evaluate to the .c file. An example for making
optimized .o files from .c files is:
.c.o:
cc -c -O $*.c
or:
.c.o:
cc -c -O $<
$? The $? macro is evaluated when explicit rules from the
makefile are evaluated. It is the list of prere-
quisites that are outdated with respect to the target,
and essentially those modules that must be rebuilt.
$% The $% macro is only evaluated when the target is an
archive library member of the form lib(file.o). In
this case, $@ evaluates to lib and $% evaluates to the
library member, file.o.
Four of the five macros can have alternative forms. When an
upper case D or F is appended to any of the four macros, the
meaning is changed to "directory part" for D and "file part"
for F. Thus, $(@D) refers to the directory part of the
string $@. If there is no directory part, ./ is generated.
The only macro excluded from this alternative form is $?.
Suffixes
Certain names (for instance, those ending with .o) have
inferable prerequisites such as .c, .s, etc. If no update
commands for such a file appear in makefile, and if an
inferable prerequisite exists, that prerequisite is compiled
to make the target. In this case, make has inference rules
that allow building files from other files by examining the
suffixes and determining an appropriate inference rule to
use. The current default inference rules are:
.c .c~ .f .f~ .s .s~ .sh .sh~ .C .C~
.c.a .c.o .c~.a .c~.c .c~.o .f.a .f.o .f~.a .f~.f .f~.o
.h~.h .l.c .l.o .l~.c .l~.l .l~.o .s.a .s.o .s~.a .s~.o
.s~.s .sh~.sh .y.c .y.o .y~.c .y~.o .y~.y .C.a .C.o .C~.a
.C~.C .C~.o .L.C .L.o .L~.C .L~.L .L~.o .Y.C .Y.o .Y~.C
.Y~.o .Y~.Y
The internal rules for make are contained in the source file
make.rules for the make program. These rules can be locally
modified. To print out the rules compiled into the make on
any machine in a form suitable for recompilation, the fol-
lowing command is used:
make -pf - 2>/dev/null </dev/null
A tilde in the above rules refers to an SCCS file (see
sccsfile(4)). Thus, the rule .c~.o would transform an SCCS C
source file into an object file (.o). Because the s. of the
SCCS files is a prefix, it is incompatible with the make
suffix point of view. Hence, the tilde is a way of changing
any file reference into an SCCS file reference.
A rule with only one suffix (for example, .c:) is the
definition of how to build x from x.c. In effect, the other
suffix is null. This feature is useful for building targets
from only one source file, for example, shell procedures and
simple C programs.
Additional suffixes are given as the dependency list for
.SUFFIXES. Order is significant: the first possible name for
which both a file and a rule exist is inferred as a prere-
quisite. The default list is:
.SUFFIXES: .o .c .c~ .y .y~ .l .l~ .s .s~ .sh .sh~ .h .h~ .f
.f~ .C .C~ .Y .Y~ .L .L~
Here again, the above command for printing the internal
rules will display the list of suffixes implemented on the
current machine. Multiple suffix lists accumulate; .SUF-
FIXES: with no dependencies clears the list of suffixes.
Inference Rules
The first example can be done more briefly.
pgm: a.o b.o
cc a.o b.o -o pgm
a.o b.o: incl.h
This abbreviation is possible because make has a set of
internal rules for building files. The user may add rules to
this list by simply putting them in the makefile.
Certain macros are used by the default inference rules to
permit the inclusion of optional matter in any resulting
commands. For example, CFLAGS, LFLAGS, and YFLAGS are used
for compiler options to cc(1B). Again, the previous method
for examining the current rules is recommended.
The inference of prerequisites can be controlled. The rule
to create a file with suffix .o from a file with suffix .c
is specified as an entry with .c.o: as the target and no
dependents. Shell commands associated with the target define
the rule for making a .o file from a .c file. Any target
that has no slashes in it and starts with a dot is identi-
fied as a rule and not a true target.
Libraries
If a target or dependency name contains parentheses, it is
assumed to be an archive library, the string within
parentheses referring to a member within the library. Thus,
lib(file.o) and $(LIB)(file.o) both refer to an archive
library that contains file.o. (This example assumes the LIB
macro has been previously defined.) The expression
$(LIB)(file1.o file2.o) is not legal. Rules pertaining to
archive libraries have the form .XX.a where the XX is the
suffix from which the archive member is to be made. An
unfortunate by-product of the current implementation
requires the XX to be different from the suffix of the
archive member. Thus, one cannot have lib(file.o) depend
upon file.o explicitly. The most common use of the archive
interface follows. Here, we assume the source files are all
C type source:
lib: lib(file1.o) lib(file2.o) lib(file3.o)
@echo lib is now up-to-date
.c.a:
$(CC) -c $(CFLAGS) $<
$(AR) $(ARFLAGS) $@ $*.o
rm -f $*.o
In fact, the .c.a rule listed above is built into make and
is unnecessary in this example. A more interesting, but more
limited example of an archive library maintenance
construction follows:
lib: lib(file1.o) lib(file2.o) lib(file3.o)
$(CC) -c $(CFLAGS) $(?:.o=.c)
$(AR) $(ARFLAGS) lib $?
rm $?
@echo lib is now up-to-date
.c.a:;
Here the substitution mode of the macro expansions is used.
The $? list is defined to be the set of object filenames
(inside lib) whose C source files are outdated. The substi-
tution mode translates the .o to .c. (Unfortunately, one
cannot as yet transform to .c~; however, this transformation
may become possible in the future.) Also note the disabling
of the .c.a: rule, which would have created each object
file, one by one. This particular construct speeds up
archive library maintenance considerably. This type of con-
struct becomes very cumbersome if the archive library con-
tains a mix of assembly programs and C programs.
ENVIRONMENT VARIABLES
USE_SVR4_MAKE
If this environment variable is set, then the make
command will invoke this System V version of make. If
this variable is not set, then the default version of
make(1S) is invoked.
USE_SVR4_MAKE can be set as follows (Bourne shell):
$ USE_SVR4_MAKE=``''; export USE_SVR4_MAKE
or (C shell):
% setenv USE_SVR4_MAKE
FILES
[Mm]akefile
s.[Mm]akefile
default makefiles
/usr/bin/sh
default shell for make
/usr/share/lib/make/make.rules
default rules for make
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWsprot |
|_____________________________|_____________________________|
SEE ALSO
cc(1B), cd(1), make(1S), sh(1), printf(3C), sccsfile(4),
attributes(5)
NOTES
Some commands return non-zero status inappropriately; use -i
or the `-' command line prefix to overcome the difficulty.
Filenames containing the characters `=', `:', and `@' will
not work. Commands that are directly executed by the shell,
notably cd(1), are ineffectual across NEWLINEs in make. The
syntax lib(file1.o file2.o file3.o) is illegal. You cannot
build lib(file.o) from file.o.
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