MAKE(1L)MAKE(1L)NAMEgnumake - GNU make utility to maintain groups of programs
SYNOPSISgnumake [ -f makefile ] [ option ] ... target ...
DESCRIPTION
The purpose of the gnumake utility is to determine automatically which
pieces of a large program need to be recompiled, and issue the commands
to recompile them. This manual describes the GNU implementation of
make, which was written by Richard Stallman and Roland McGrath. It is
a tool commonly used with C programs, but you can use gnumake with any
programming language whose compiler can be run with a shell command.
In fact, gnumake is not limited to programs. You can use it to
describe any task where some files must be updated automatically from
others whenever the others change.
To prepare to use gnumake, you must write a file called the makefile
that describes the relationships among files in your program, and the
states the commands for updating each file. In a program, typically
the executable file is updated from object files, which are in turn
made by compiling source files.
Once a suitable makefile exists, each time you change some source
files, this simple shell command:
gnumake
suffices to perform all necessary recompilations. The gnumake program
uses the makefile data base and the last-modification times of the
files to decide which of the files need to be updated. For each of
those files, it issues the commands recorded in the data base.
gnumake executes commands in the makefile to update one or more target
names, where name is typically a program. If no -f option is present,
gnumake will look for the makefiles GNUmakefile, makefile, and
Makefile, in that order.
Normally you should call your makefile either makefile or Makefile.
(We recommend Makefile because it appears prominently near the
beginning of a directory listing, right near other important files such
as README.) The first name checked, GNUmakefile, is not recommended
for most makefiles. You should use this name if you have a makefile
that is specific to GNU make, and will not be understood by other
versions of make. If makefile is `-', the standard input is read.
gnumake 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.
OPTIONS-b
-m These options are ignored for compatibility with other versions of
make.
-C dir
Change to directory dir before reading the makefiles or doing
anything else. If multiple -C options are specified, each is
interpreted relative to the previous one: -C / -C etc is
equivalent to -C /etc. This is typically used with recursive
invocations of gnumake.
-d Print debugging information in addition to normal processing. The
debugging information says which files are being considered for
remaking, which file-times are being compared and with what
results, which files actually need to be remade, which implicit
rules are considered and which are applied---everything
interesting about how gnumake decides what to do.
-e Give variables taken from the environment precedence over
variables from makefiles.
-f file
Use file as a makefile.
-i Ignore all errors in commands executed to remake files.
-I dir
Specifies a directory dir to search for included makefiles. If
several -I options are used to specify several directories, the
directories are searched in the order specified. Unlike the
arguments to other flags of gnumake, directories given with -I
flags may come directly after the flag: -Idir is allowed, as well
as -I dir. This syntax is allowed for compatibility with the C
preprocessor's -I flag.
-j jobs
Specifies the number of jobs (commands) to run simultaneously. If
there is more than one -j option, the last one is effective. If
the -j option is given without an argument, gnumake will not limit
the number of jobs that can run simultaneously.
-k Continue as much as possible after an error. While the target
that failed, and those that depend on it, cannot be remade, the
other dependencies of these targets can be processed all the same.
-l
-l load
Specifies that no new jobs (commands) should be started if there
are others jobs running and the load average is at least load (a
floating-point number). With no argument, removes a previous load
limit.
-n Print the commands that would be executed, but do not execute
them.
-N OPTION
Disable a NeXT make compatibility feature. OPTION can be one of
the following;
-N all
Disable all NeXT features.
-N caret
Don't alias the caret variable ($^) to $>.
-N findfile
Don't support the NeXT findfile directive.
-N makefiles
Don't avoid remaking Makefiles. By default, GNU make as shipped
from FSF attempts to build Makefiles. NeXT has turned this
feature off, but it can be turned back on using this option.
-N quiet
Don't be quiet. Vebose messages warn about using vpath
compatiblity mode, missing targets and overriding implicit rules.
-N vpath
Don't use the SystemV vpath compatibility mode.
-o file
Do not remake the file file even if it is older than its
dependencies, and do not remake anything on account of changes in
file. Essentially the file is treated as very old and its rules
are ignored.
-p Print the data base (rules and variable values) that results from
reading the makefiles; then execute as usual or as otherwise
specified. This also prints the version information given by the
-v switch (see below). To print the data base without trying to
remake any files, use gnumake-p -f/dev/null.
-q ``Question mode''. Do not run any commands, or print anything;
just return an exit status that is zero if the specified targets
are already up to date, nonzero otherwise.
-r Eliminate use of the built-in implicit rules. Also clear out the
default list of suffixes for suffix rules.
-s Silent operation; do not print the commands as they are executed.
-S Cancel the effect of the -k option. This is never necessary
except in a recursive gnumake where -k might be inherited from the
top-level gnumake via MAKEFLAGS or if you set -k in MAKEFLAGS in
your environment.
-t Touch files (mark them up to date without really changing them)
instead of running their commands. This is used to pretend that
the commands were done, in order to fool future invocations of
gnumake.
-v Print the version of the gnumake program plus a copyright, a list
of authors and a notice that there is no warranty. After this
information is printed, processing continues normally. To get
this information without doing anything else, use gnumake-v
-f/dev/null.
-w Print a message containing the working directory before and after
other processing. This may be useful for tracking down errors
from complicated nests of recursive gnumake commands.
-W file
Pretend that the target file has just been modified. When used
with the -n flag, this shows you what would happen if you were to
modify that file. Without -n, it is almost the same as running a
touch command on the given file before running gnumake, except
that the modification time is changed only in the imagination of
gnumake.
SEE ALSO
You can access "The GNU Make Manual" and other tools documentation on
the World Wide Web at www.cygnus.com/doc.
BUGS
See the chapter `Problems and Bugs' in The GNU Make Manual .
AUTHOR
This manual page contributed by Dennis Morse of Stanford University.
It has been reworked by Roland McGrath.
NeXT Software, Inc. March 18, 1996 MAKE(1L)