MAKE

NAME

SYNOPSIS

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

BUGS

AUTHOR

Index

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

SEE ALSO

BUGS

AUTHOR