SYSV-MAKE(1) User Commands SYSV-MAKE(1)


NAME


sysV-make - maintain, update, and regenerate groups of programs

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 regenerate groups of
computer programs. make executes commands in makefile to update one or
more target names (names are typically 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 Missing files are deemed to be outdated.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 commands
or relevant built-in rules, the commands associated 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 executing.


-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 dependencies. 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
definition. 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 contained
`\-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 Environment 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 character 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 specified, 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" dependent 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 prerequisites 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
re-compilation, the following command is used:

make -pf -2>/dev/null < /dev/null


A tilde in the above rules refers to an SCCS file (see sccsfile(5)).
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 prerequisite. 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; .SUFFIXES: 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. 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 identified 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 substitution 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 construct becomes very cumbersome
if the archive library contains 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


SEE ALSO


cd(1), sh(1), make(1S), printf(3C), sccsfile(5), attributes(7)

NOTES


Some commands return non-zero status inappropriately; use -i or the `-'
command line prefix to overcome the difficulty.


Filenames containing the characters =, :, and @ do 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.


August 24, 2009 SYSV-MAKE(1)