| @comment This file is included by both standards.texi and make.texinfo. |
| @comment It was broken out of standards.texi on 1/6/93 by roland. |
| |
| @node Makefile Conventions |
| @chapter Makefile Conventions |
| @comment standards.texi does not print an index, but make.texinfo does. |
| @cindex makefile, conventions for |
| @cindex conventions for makefiles |
| @cindex standards for makefiles |
| |
| This chapter describes conventions for writing the Makefiles for GNU programs. |
| |
| @menu |
| * Makefile Basics:: |
| * Utilities in Makefiles:: |
| * Standard Targets:: |
| * Command Variables:: |
| * Directory Variables:: |
| @end menu |
| |
| @node Makefile Basics |
| @section General Conventions for Makefiles |
| |
| Every Makefile should contain this line: |
| |
| @example |
| SHELL = /bin/sh |
| @end example |
| |
| @noindent |
| to avoid trouble on systems where the @code{SHELL} variable might be |
| inherited from the environment. (This is never a problem with GNU |
| @code{make}.) |
| |
| Don't assume that @file{.} is in the path for command execution. When |
| you need to run programs that are a part of your package during the |
| make, please make sure that it uses @file{./} if the program is built as |
| part of the make or @file{$(srcdir)/} if the file is an unchanging part |
| of the source code. Without one of these prefixes, the current search |
| path is used. |
| |
| The distinction between @file{./} and @file{$(srcdir)/} is important |
| when using the @samp{--srcdir} option to @file{configure}. A rule of |
| the form: |
| |
| @example |
| foo.1 : foo.man sedscript |
| sed -e sedscript foo.man > foo.1 |
| @end example |
| |
| @noindent |
| will fail when the current directory is not the source directory, |
| because @file{foo.man} and @file{sedscript} are not in the current |
| directory. |
| |
| Relying on @samp{VPATH} to find the source file will work in the case |
| where there is a single dependency file, since the @file{make} automatic |
| variable @samp{$<} will represent the source file wherever it is. A |
| makefile target like |
| |
| @example |
| foo.o : bar.c |
| $(CC) $(CFLAGS) -I. -I$(srcdir) -c bar.c -o foo.o |
| @end example |
| |
| @noindent |
| should instead be written as |
| |
| @example |
| foo.o : bar.c |
| $(CC) $(CFLAGS) $< -o $@@ |
| @end example |
| |
| @noindent |
| in order to allow @samp{VPATH} to work correctly. When the target has |
| multiple dependencies, using an explicit @samp{$(srcdir)} is the easiest |
| way to make the rule work well. For example, the target above for |
| @file{foo.1} is best written as: |
| |
| @example |
| foo.1 : foo.man sedscript |
| sed -s $(srcdir)/sedscript $(srcdir)/foo.man > foo.1 |
| @end example |
| |
| @node Utilities in Makefiles |
| @section Utilities in Makefiles |
| |
| Write the Makefile commands (and any shell scripts, such as |
| @code{configure}) to run in @code{sh}, not in @code{csh}. Don't use any |
| special features of @code{ksh} or @code{bash}. |
| |
| The @code{configure} script and the Makefile rules for building and |
| installation should not use any utilities directly except these: |
| |
| @example |
| cat cmp cp echo egrep expr grep |
| ln mkdir mv pwd rm rmdir sed test touch |
| @end example |
| |
| Stick to the generally supported options for these programs. For |
| example, don't use @samp{mkdir -p}, convenient as it may be, because |
| most systems don't support it. |
| |
| The Makefile rules for building and installation can also use compilers |
| and related programs, but should do so via @code{make} variables so that the |
| user can substitute alternatives. Here are some of the programs we |
| mean: |
| |
| @example |
| ar bison cc flex install ld lex make ranlib yacc |
| @end example |
| |
| When you use @code{ranlib}, you should test whether it exists, and run |
| it only if it exists, so that the distribution will work on systems that |
| don't have @code{ranlib}. |
| |
| If you use symbolic links, you should implement a fallback for systems |
| that don't have symbolic links. |
| |
| It is ok to use other utilities in Makefile portions (or scripts) |
| intended only for particular systems where you know those utilities to |
| exist. |
| |
| @node Standard Targets |
| @section Standard Targets for Users |
| |
| All GNU programs should have the following targets in their Makefiles: |
| |
| @table @samp |
| @item all |
| Compile the entire program. This should be the default target. This |
| target need not rebuild any documentation files; info files should |
| normally be included in the distribution, and DVI files should be made |
| only when explicitly asked for. |
| |
| @item install |
| Compile the program and copy the executables, libraries, and so on to |
| the file names where they should reside for actual use. If there is a |
| simple test to verify that a program is properly installed then run that |
| test. |
| |
| Use @samp{-} before any command for installing a man page, so that |
| @code{make} will ignore any errors. This is in case there are systems |
| that don't have the Unix man page documentation system installed. |
| |
| In the future, when we have a standard way of installing info files, |
| @samp{install} targets will be the proper place to do so. |
| |
| @item uninstall |
| Delete all the installed files that the @samp{install} target would |
| create (but not the noninstalled files such as @samp{make all} would |
| create). |
| |
| @item clean |
| Delete all files from the current directory that are normally created by |
| building the program. Don't delete the files that record the |
| configuration. Also preserve files that could be made by building, but |
| normally aren't because the distribution comes with them. |
| |
| Delete @file{.dvi} files here if they are not part of the distribution. |
| |
| @item distclean |
| Delete all files from the current directory that are created by |
| configuring or building the program. If you have unpacked the source |
| and built the program without creating any other files, @samp{make |
| distclean} should leave only the files that were in the distribution. |
| |
| @item mostlyclean |
| Like @samp{clean}, but may refrain from deleting a few files that people |
| normally don't want to recompile. For example, the @samp{mostlyclean} |
| target for GCC does not delete @file{libgcc.a}, because recompiling it |
| is rarely necessary and takes a lot of time. |
| |
| @item realclean |
| Delete everything from the current directory that can be reconstructed |
| with this Makefile. This typically includes everything deleted by |
| distclean, plus more: C source files produced by Bison, tags tables, |
| info files, and so on. |
| |
| One exception, however: @samp{make realclean} should not delete |
| @file{configure} even if @file{configure} can be remade using a rule in |
| the Makefile. More generally, @samp{make realclean} should not delete |
| anything that needs to exist in order to run @file{configure} |
| and then begin to build the program. |
| |
| @item TAGS |
| Update a tags table for this program. |
| |
| @item info |
| Generate any info files needed. The best way to write the rules is as |
| follows: |
| |
| @example |
| info: foo.info |
| |
| foo.info: $(srcdir)/foo.texi $(srcdir)/chap1.texi $(srcdir)/chap2.texi |
| $(MAKEINFO) $(srcdir)/foo.texi |
| @end example |
| |
| @noindent |
| You must define the variable @code{MAKEINFO} in the Makefile. |
| It should run the Makeinfo program, which is part of the Texinfo2 distribution. |
| |
| @item dvi |
| Generate DVI files for all TeXinfo documentation. |
| For example: |
| |
| @example |
| dvi: foo.dvi |
| |
| foo.dvi: $(srcdir)/foo.texi $(srcdir)/chap1.texi $(srcdir)/chap2.texi |
| $(TEXI2DVI) $(srcdir)/foo.texi |
| @end example |
| |
| @noindent |
| You must define the variable @code{TEXI2DVI} in the Makefile. It should |
| run the program @code{texi2dvi}, which is part of the Texinfo2 |
| distribution. Alternatively, write just the dependencies, and allow GNU |
| Make to provide the command. |
| |
| @item dist |
| Create a distribution tar file for this program. The tar file should be |
| set up so that the file names in the tar file start with a subdirectory |
| name which is the name of the package it is a distribution for. This |
| name can include the version number. |
| |
| For example, the distribution tar file of GCC version 1.40 unpacks into |
| a subdirectory named @file{gcc-1.40}. |
| |
| The easiest way to do this is to create a subdirectory appropriately |
| named, use @code{ln} or @code{cp} to install the proper files in it, and |
| then @code{tar} that subdirectory. |
| |
| The @code{dist} target should explicitly depend on all non-source files |
| that are in the distribution, to make sure they are up to date in the |
| distribution. |
| @xref{Releases, , Making Releases, standards, GNU Coding Standards}. |
| |
| @item check |
| Perform self-tests (if any). The user must build the program before |
| running the tests, but need not install the program; you should write |
| the self-tests so that they work when the program is built but not |
| installed. |
| @end table |
| |
| @node Command Variables |
| @section Variables for Specifying Commands |
| |
| Makefiles should provide variables for overriding certain commands, options, |
| and so on. |
| |
| In particular, you should run most utility programs via variables. |
| Thus, if you use Bison, have a variable named @code{BISON} whose default |
| value is set with @samp{BISON = bison}, and refer to it with |
| @code{$(BISON)} whenever you need to use Bison. |
| |
| File management utilities such as @code{ln}, @code{rm}, @code{mv}, and |
| so on, need not be referred to through variables in this way, since users |
| don't need to replace them with other programs. |
| |
| Each program-name variable should come with an options variable that is |
| used to supply options to the program. Append @samp{FLAGS} to the |
| program-name variable name to get the options variable name---for |
| example, @code{BISONFLAGS}. (The name @code{CFLAGS} is an exception to |
| this rule, but we keep it because it is standard.) Use @code{CPPFLAGS} |
| in any compilation command that runs the preprocessor, and use |
| @code{LDFLAGS} in any compilation command that does linking as well as |
| in any direct use of @code{ld}. |
| |
| If there are C compiler options that @emph{must} be used for proper |
| compilation of certain files, do not include them in @code{CFLAGS}. |
| Users expect to be able to specify @code{CFLAGS} freely themselves. |
| Instead, arrange to pass the necessary options to the C compiler |
| independently of @code{CFLAGS}, by writing them explicitly in the |
| compilation commands or by defining an implicit rule, like this: |
| |
| @example |
| CFLAGS = -g |
| ALL_CFLAGS = $(CFLAGS) -I. |
| .c.o: |
| $(CC) -c $(ALL_CFLAGS) $(CPPFLAGS) $< |
| @end example |
| |
| Do include the @samp{-g} option in @code{CFLAGS}, because that is not |
| @emph{required} for proper compilation. You can consider it a default |
| that is only recommended. If the package is set up so that it is |
| compiled with GCC by default, then you might as well include @samp{-O} |
| in the default value of @code{CFLAGS} as well. |
| |
| Every Makefile should define the variable @code{INSTALL}, which is the |
| basic command for installing a file into the system. |
| |
| Every Makefile should also define variables @code{INSTALL_PROGRAM} and |
| @code{INSTALL_DATA}. (The default for each of these should be |
| @code{$(INSTALL)}.) Then it should use those variables as the commands |
| for actual installation, for executables and nonexecutables |
| respectively. Use these variables as follows: |
| |
| @example |
| $(INSTALL_PROGRAM) foo $(bindir)/foo |
| $(INSTALL_DATA) libfoo.a $(libdir)/libfoo.a |
| @end example |
| |
| @noindent |
| Always use a file name, not a directory name, as the second argument of |
| the installation commands. Use a separate command for each file to be |
| installed. |
| |
| @node Directory Variables |
| @section Variables for Installation Directories |
| |
| Installation directories should always be named by variables, so it is |
| easy to install in a nonstandard place. The standard names for these |
| variables are: |
| |
| @table @samp |
| @item prefix |
| A prefix used in constructing the default values of the variables listed |
| below. The default value of @code{prefix} should be @file{/usr/local} |
| (at least for now). |
| |
| @item exec_prefix |
| A prefix used in constructing the default values of the some of the |
| variables listed below. The default value of @code{exec_prefix} should |
| be @code{$(prefix)}. |
| |
| Generally, @code{$(exec_prefix)} is used for directories that contain |
| machine-specific files (such as executables and subroutine libraries), |
| while @code{$(prefix)} is used directly for other directories. |
| |
| @item bindir |
| The directory for installing executable programs that users can run. |
| This should normally be @file{/usr/local/bin}, but write it as |
| @file{$(exec_prefix)/bin}. |
| |
| @item libdir |
| The directory for installing executable files to be run by the program |
| rather than by users. Object files and libraries of object code should |
| also go in this directory. The idea is that this directory is used for |
| files that pertain to a specific machine architecture, but need not be |
| in the path for commands. The value of @code{libdir} should normally be |
| @file{/usr/local/lib}, but write it as @file{$(exec_prefix)/lib}. |
| |
| @item datadir |
| The directory for installing read-only data files which the programs |
| refer to while they run. This directory is used for files which are |
| independent of the type of machine being used. This should normally be |
| @file{/usr/local/lib}, but write it as @file{$(prefix)/lib}. |
| |
| @item statedir |
| The directory for installing data files which the programs modify while |
| they run. These files should be independent of the type of machine |
| being used, and it should be possible to share them among machines at a |
| network installation. This should normally be @file{/usr/local/lib}, |
| but write it as @file{$(prefix)/lib}. |
| |
| @item includedir |
| @c rewritten to avoid overfull hbox --roland |
| The directory for installing header files to be included by user |
| programs with the C @samp{#include} preprocessor directive. This |
| should normally be @file{/usr/local/include}, but write it as |
| @file{$(prefix)/include}. |
| |
| Most compilers other than GCC do not look for header files in |
| @file{/usr/local/include}. So installing the header files this way is |
| only useful with GCC. Sometimes this is not a problem because some |
| libraries are only really intended to work with GCC. But some libraries |
| are intended to work with other compilers. They should install their |
| header files in two places, one specified by @code{includedir} and one |
| specified by @code{oldincludedir}. |
| |
| @item oldincludedir |
| The directory for installing @samp{#include} header files for use with |
| compilers other than GCC. This should normally be @file{/usr/include}. |
| |
| The Makefile commands should check whether the value of |
| @code{oldincludedir} is empty. If it is, they should not try to use |
| it; they should cancel the second installation of the header files. |
| |
| A package should not replace an existing header in this directory unless |
| the header came from the same package. Thus, if your Foo package |
| provides a header file @file{foo.h}, then it should install the header |
| file in the @code{oldincludedir} directory if either (1) there is no |
| @file{foo.h} there or (2) the @file{foo.h} that exists came from the Foo |
| package. |
| |
| The way to tell whether @file{foo.h} came from the Foo package is to put |
| a magic string in the file---part of a comment---and grep for that |
| string. |
| |
| @item mandir |
| The directory for installing the man pages (if any) for this package. |
| It should include the suffix for the proper section of the |
| manual---usually @samp{1} for a utility. |
| |
| @item man1dir |
| The directory for installing section 1 man pages. |
| @item man2dir |
| The directory for installing section 2 man pages. |
| @item @dots{} |
| Use these names instead of @samp{mandir} if the package needs to install man |
| pages in more than one section of the manual. |
| |
| @strong{Don't make the primary documentation for any GNU software be a |
| man page. Write a manual in Texinfo instead. Man pages are just for |
| the sake of people running GNU software on Unix, which is a secondary |
| application only.} |
| |
| @item manext |
| The file name extension for the installed man page. This should contain |
| a period followed by the appropriate digit. |
| |
| @item infodir |
| The directory for installing the info files for this package. By |
| default, it should be @file{/usr/local/info}, but it should be written |
| as @file{$(prefix)/info}. |
| |
| @item srcdir |
| The directory for the sources being compiled. The value of this |
| variable is normally inserted by the @code{configure} shell script. |
| @end table |
| |
| For example: |
| |
| @example |
| @c I have changed some of the comments here slightly to fix an overfull |
| @c hbox, so the make manual can format correctly. --roland |
| # Common prefix for installation directories. |
| # NOTE: This directory must exist when you start the install. |
| prefix = /usr/local |
| exec_prefix = $(prefix) |
| # Where to put the executable for the command `gcc'. |
| bindir = $(exec_prefix)/bin |
| # Where to put the directories used by the compiler. |
| libdir = $(exec_prefix)/lib |
| # Where to put the Info files. |
| infodir = $(prefix)/info |
| @end example |
| |
| If your program installs a large number of files into one of the |
| standard user-specified directories, it might be useful to group them |
| into a subdirectory particular to that program. If you do this, you |
| should write the @code{install} rule to create these subdirectories. |
| |
| Do not expect the user to include the subdirectory name in the value of |
| any of the variables listed above. The idea of having a uniform set of |
| variable names for installation directories is to enable the user to |
| specify the exact same values for several different GNU packages. In |
| order for this to be useful, all the packages must be designed so that |
| they will work sensibly when the user does so. |
| |