| .TH MAKE 1L "22 August 1989" "GNU" "LOCAL USER COMMANDS" |
| .SH NAME |
| make \- GNU make utility to maintain groups of programs |
| .SH SYNOPSIS |
| .B "make " |
| [ |
| .B \-f |
| makefile ] [ option ] ... |
| target ... |
| .SH WARNING |
| This man paage is an extract of the documentation of |
| .I GNU make . |
| It is updated only occasionally, because the GNU project does not use nroff. |
| For complete, current documentation, refer to the Info file |
| .B make |
| or the DVI file |
| .B make.dvi |
| which are made from the Texinfo source file |
| .BR make.texinfo . |
| .SH DESCRIPTION |
| .LP |
| The purpose of the |
| .I make |
| 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 |
| .IR make , |
| which was written by Richard Stallman and Roland McGrath. |
| Our examples show C programs, since they are most common, but you can use |
| .I make |
| with any programming language whose compiler can be run with a |
| shell command. |
| In fact, |
| .I make |
| 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. |
| .LP |
| To prepare to use |
| .IR make , |
| you must write a file called the |
| .I 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. |
| .LP |
| Once a suitable makefile exists, each time you change some source files, |
| this simple shell command: |
| .sp 1 |
| .RS |
| .B make |
| .RE |
| .sp 1 |
| suffices to perform all necessary recompilations. |
| The |
| .I make |
| 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. |
| .LP |
| .I make |
| executes commands in the |
| .I makefile |
| to update |
| one or more target |
| .IR names , |
| where |
| .I name |
| is typically a program. |
| If no |
| .B \-f |
| option is present, |
| .I make |
| will look for the makefiles |
| .IR GNUmakefile , |
| .IR makefile , |
| and |
| .IR Makefile , |
| in that order. |
| .LP |
| Normally you should call your makefile either |
| .I makefile |
| or |
| .IR Makefile . |
| (We recommend |
| .I Makefile |
| because it appears prominently near the beginning of a directory |
| listing, right near other important files such as |
| .IR README .) |
| The first name checked, |
| .IR GNUmakefile , |
| is not recommended for most makefiles. |
| You should use this name if you have a makefile that is specific to GNU |
| .IR make , |
| and will not be understood by other versions of |
| .IR make . |
| If |
| .I makefile |
| is `\-', the standard input is read. |
| .LP |
| .I 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. |
| .SH OPTIONS |
| .sp 1 |
| .TP 0.5i |
| .B \-b |
| .TP 0.5i |
| .B \-m |
| These options are ignored for compatibility with other versions of |
| .IR make . |
| .TP 0.5i |
| .BI "\-C " dir |
| Change to directory |
| .I dir |
| before reading the makefiles or doing anything else. |
| If multiple |
| .B \-C |
| options are specified, each is interpreted relative to the |
| previous one: |
| .BR "\-C " / |
| .BR "\-C " etc |
| is equivalent to |
| .BR "\-C " /etc. |
| This is typically used with recursive invocations of |
| .IR make . |
| .TP 0.5i |
| .B \-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 |
| .I make |
| decides what to do. |
| .TP 0.5i |
| .B \-e |
| Give variables taken from the environment precedence |
| over variables from makefiles. |
| .TP 0.5i |
| .BI "\-f " file |
| Use |
| .I file |
| as a makefile. |
| .TP 0.5i |
| .B \-i |
| Ignore all errors in commands executed to remake files. |
| .TP 0.5i |
| .BI "\-I " dir |
| Specifies a directory |
| .I dir |
| to search for included makefiles. |
| If several |
| .B \-I |
| options are used to specify several directories, the directories are |
| searched in the order specified. |
| Unlike the arguments to other flags of |
| .IR make , |
| directories given with |
| .B \-I |
| flags may come directly after the flag: |
| .BI \-I dir |
| is allowed, as well as |
| .BI "\-I " dir. |
| This syntax is allowed for compatibility with the C |
| preprocessor's |
| .B \-I |
| flag. |
| .TP 0.5i |
| .BI "\-j " jobs |
| Specifies the number of jobs (commands) to run simultaneously. |
| If there is more than one |
| .B \-j |
| option, the last one is effective. |
| If the |
| .B \-j |
| option is given without an argument, |
| .IR make |
| will not limit the number of jobs that can run simultaneously. |
| .TP 0.5i |
| .B \-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. |
| .TP 0.5i |
| .B \-l |
| .TP 0.5i |
| .BI "\-l " load |
| Specifies that no new jobs (commands) should be started if there are |
| others jobs running and the load average is at least |
| .I load |
| (a floating-point number). |
| With no argument, removes a previous load limit. |
| .TP 0.5i |
| .B \-n |
| Print the commands that would be executed, but do not execute them. |
| .TP 0.5i |
| .BI "\-o " file |
| Do not remake the file |
| .I file |
| even if it is older than its dependencies, and do not remake anything |
| on account of changes in |
| .IR file . |
| Essentially the file is treated as very old and its rules are ignored. |
| .TP 0.5i |
| .B \-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 |
| .B \-v |
| switch (see below). |
| To print the data base without trying to remake any files, use |
| .B make |
| .B \-p |
| .BI \-f /dev/null. |
| .TP 0.5i |
| .B \-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. |
| .TP 0.5i |
| .B \-r |
| Eliminate use of the built-in implicit rules. |
| Also clear out the default list of suffixes for suffix rules. |
| .TP 0.5i |
| .B \-s |
| Silent operation; do not print the commands as they are executed. |
| .TP 0.5i |
| .B \-S |
| Cancel the effect of the |
| .B \-k |
| option. |
| This is never necessary except in a recursive |
| .I make |
| where |
| .B \-k |
| might be inherited from the top-level |
| .I make |
| via MAKEFLAGS or if you set |
| .B \-k |
| in MAKEFLAGS in your environment. |
| .TP 0.5i |
| .B \-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 |
| .IR make . |
| .TP 0.5i |
| .B \-v |
| Print the version of the |
| .I make |
| 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 |
| .B make |
| .B \-v |
| .BI \-f /dev/null. |
| .TP 0.5i |
| .B \-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 |
| .I make |
| commands. |
| .TP 0.5i |
| .BI "\-W " file |
| Pretend that the target |
| .I file |
| has just been modified. |
| When used with the |
| .B \-n |
| flag, this shows you what would happen if you were to modify that file. |
| Without |
| .BR \-n , |
| it is almost the same as running a |
| .I touch |
| command on the given file before running |
| .IR make , |
| except that the modification time is changed only in the imagination of |
| .IR make . |
| .SH "SEE ALSO" |
| .PD 0 |
| .TP 2.0i |
| /usr/local/doc/gnumake.dvi |
| .I |
| The GNU Make Manual |
| .PD |
| .SH BUGS |
| See the chapter `Problems and Bugs' in |
| .I "The GNU Make Manual" . |
| .SH AUTHOR |
| This manual page contributed by Dennis Morse of Stanford University. |
| It has been reworked by Roland McGrath. |