- Stick to the generally supported options for these programs. For
-example, don't use `mkdir -p', convenient as it may be, because most
-systems don't support it.
-
- It is a good idea to avoid creating symbolic links in makefiles,
-since a few systems don't support them.
-
- The Makefile rules for building and installation can also use
-compilers and related programs, but should do so via `make' variables
-so that the user can substitute alternatives. Here are some of the
-programs we mean:
-
- ar bison cc flex install ld lex
- make makeinfo ranlib texi2dvi yacc
-
- Use the following `make' variables:
-
- $(AR) $(BISON) $(CC) $(FLEX) $(INSTALL) $(LD) $(LEX)
- $(MAKE) $(MAKEINFO) $(RANLIB) $(TEXI2DVI) $(YACC)
-
- When you use `ranlib', you should make sure nothing bad happens if
-the system does not have `ranlib'. Arrange to ignore an error from
-that command, and print a message before the command to tell the user
-that failure of the `ranlib' command does not mean a problem. (The
-Autoconf `AC_PROG_RANLIB' macro can help with this.)
-
- If you use symbolic links, you should implement a fallback for
-systems that don't have symbolic links.
-
- It is ok to use other utilities in Makefile portions (or scripts)
-intended only for particular systems where you know those utilities
-exist.
-
-\1f
-File: standards.info, Node: Command Variables, Next: Directory Variables, Prev: Utilities in Makefiles, Up: Makefile Conventions
-
-Variables for Specifying Commands
----------------------------------
-
- Makefiles should provide variables for overriding certain commands,
-options, and so on.
-
- In particular, you should run most utility programs via variables.
-Thus, if you use Bison, have a variable named `BISON' whose default
-value is set with `BISON = bison', and refer to it with `$(BISON)'
-whenever you need to use Bison.
-
- File management utilities such as `ln', `rm', `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 `FLAGS' to the
-program-name variable name to get the options variable name--for
-example, `BISONFLAGS'. (The name `CFLAGS' is an exception to this
-rule, but we keep it because it is standard.) Use `CPPFLAGS' in any
-compilation command that runs the preprocessor, and use `LDFLAGS' in
-any compilation command that does linking as well as in any direct use
-of `ld'.
-
- If there are C compiler options that *must* be used for proper
-compilation of certain files, do not include them in `CFLAGS'. Users
-expect to be able to specify `CFLAGS' freely themselves. Instead,
-arrange to pass the necessary options to the C compiler independently
-of `CFLAGS', by writing them explicitly in the compilation commands or
-by defining an implicit rule, like this:
-
- CFLAGS = -g
- ALL_CFLAGS = -I. $(CFLAGS)
- .c.o:
- $(CC) -c $(CPPFLAGS) $(ALL_CFLAGS) $<
-
- Do include the `-g' option in `CFLAGS', because that is not
-*required* for proper compilation. You can consider it a default that
-is only recommended. If the package is set up so that it is compiled
-with GCC by default, then you might as well include `-O' in the default
-value of `CFLAGS' as well.
-
- Put `CFLAGS' last in the compilation command, after other variables
-containing compiler options, so the user can use `CFLAGS' to override
-the others.
-
- Every Makefile should define the variable `INSTALL', which is the
-basic command for installing a file into the system.
-
- Every Makefile should also define the variables `INSTALL_PROGRAM'
-and `INSTALL_DATA'. (The default for each of these should be
-`$(INSTALL)'.) Then it should use those variables as the commands for
-actual installation, for executables and nonexecutables respectively.
-Use these variables as follows:
-
- $(INSTALL_PROGRAM) foo $(bindir)/foo
- $(INSTALL_DATA) libfoo.a $(libdir)/libfoo.a
-
-Always use a file name, not a directory name, as the second argument of
-the installation commands. Use a separate command for each file to be
-installed.
-
-\1f
-File: standards.info, Node: Directory Variables, Next: Standard Targets, Prev: Command Variables, Up: Makefile Conventions
-
-Variables for Installation Directories
---------------------------------------
-
- Installation directories should always be named by variables, so it
-is easy to install in a nonstandard place. The standard names for these
-variables are described below. They are based on a standard filesystem
-layout; variants of it are used in SVR4, 4.4BSD, Linux, Ultrix v4, and
-other modern operating systems.
-
- These two variables set the root for the installation. All the other
-installation directories should be subdirectories of one of these two,
-and nothing should be directly installed into these two directories.
-
-`prefix'
- A prefix used in constructing the default values of the variables
- listed below. The default value of `prefix' should be
- `/usr/local'. When building the complete GNU system, the prefix
- will be empty and `/usr' will be a symbolic link to `/'. (If you
- are using Autoconf, write it as `@prefix@'.)
-
-`exec_prefix'
- A prefix used in constructing the default values of some of the
- variables listed below. The default value of `exec_prefix' should
- be `$(prefix)'. (If you are using Autoconf, write it as
- `@exec_prefix@'.)
-
- Generally, `$(exec_prefix)' is used for directories that contain
- machine-specific files (such as executables and subroutine
- libraries), while `$(prefix)' is used directly for other
- directories.
-
- Executable programs are installed in one of the following
-directories.
-
-`bindir'
- The directory for installing executable programs that users can
- run. This should normally be `/usr/local/bin', but write it as
- `$(exec_prefix)/bin'. (If you are using Autoconf, write it as
- `@bindir@'.)
-
-`sbindir'
- The directory for installing executable programs that can be run
- from the shell, but are only generally useful to system
- administrators. This should normally be `/usr/local/sbin', but
- write it as `$(exec_prefix)/sbin'. (If you are using Autoconf,
- write it as `@sbindir@'.)
-
-`libexecdir'
- The directory for installing executable programs to be run by other
- programs rather than by users. This directory should normally be
- `/usr/local/libexec', but write it as `$(exec_prefix)/libexec'.
- (If you are using Autoconf, write it as `@libexecdir@'.)
-
- Data files used by the program during its execution are divided into
-categories in two ways.
-
- * Some files are normally modified by programs; others are never
- normally modified (though users may edit some of these).
-
- * Some files are architecture-independent and can be shared by all
- machines at a site; some are architecture-dependent and can be
- shared only by machines of the same kind and operating system;
- others may never be shared between two machines.
-
- This makes for six different possibilities. However, we want to
-discourage the use of architecture-dependent files, aside from object
-files and libraries. It is much cleaner to make other data files
-architecture-independent, and it is generally not hard.
-
- Therefore, here are the variables Makefiles should use to specify
-directories:
-
-`datadir'
- The directory for installing read-only architecture independent
- data files. This should normally be `/usr/local/share', but write
- it as `$(prefix)/share'. (If you are using Autoconf, write it as
- `@datadir@'.) As a special exception, see `$(infodir)' and
- `$(includedir)' below.
-
-`sysconfdir'
- The directory for installing read-only data files that pertain to a
- single machine-that is to say, files for configuring a host.
- Mailer and network configuration files, `/etc/passwd', and so
- forth belong here. All the files in this directory should be
- ordinary ASCII text files. This directory should normally be
- `/usr/local/etc', but write it as `$(prefix)/etc'. (If you are
- using Autoconf, write it as `@sysconfdir@'.)
-
- Do not install executables in this directory (they probably belong
- in `$(libexecdir)' or `$(sbindir)'). Also do not install files
- that are modified in the normal course of their use (programs
- whose purpose is to change the configuration of the system
- excluded). Those probably belong in `$(localstatedir)'.
-
-`sharedstatedir'
- The directory for installing architecture-independent data files
- which the programs modify while they run. This should normally be
- `/usr/local/com', but write it as `$(prefix)/com'. (If you are
- using Autoconf, write it as `@sharedstatedir@'.)
-
-`localstatedir'
- The directory for installing data files which the programs modify
- while they run, and that pertain to one specific machine. Users
- should never need to modify files in this directory to configure
- the package's operation; put such configuration information in
- separate files that go in `$(datadir)' or `$(sysconfdir)'.
- `$(localstatedir)' should normally be `/usr/local/var', but write
- it as `$(prefix)/var'. (If you are using Autoconf, write it as
- `@localstatedir@'.)
-
-`libdir'
- The directory for object files and libraries of object code. Do
- not install executables here, they probably ought to go in
- `$(libexecdir)' instead. The value of `libdir' should normally be
- `/usr/local/lib', but write it as `$(exec_prefix)/lib'. (If you
- are using Autoconf, write it as `@libdir@'.)
-
-`infodir'
- The directory for installing the Info files for this package. By
- default, it should be `/usr/local/info', but it should be written
- as `$(prefix)/info'. (If you are using Autoconf, write it as
- `@infodir@'.)
-
-`includedir'
- The directory for installing header files to be included by user
- programs with the C `#include' preprocessor directive. This
- should normally be `/usr/local/include', but write it as
- `$(prefix)/include'. (If you are using Autoconf, write it as
- `@includedir@'.)
-
- Most compilers other than GCC do not look for header files in
- `/usr/local/include'. So installing the header files this way is
- only useful with GCC. Sometimes this is not a problem because some
- libraries are only really intended to work with GCC. But some
- libraries are intended to work with other compilers. They should
- install their header files in two places, one specified by
- `includedir' and one specified by `oldincludedir'.
-
-`oldincludedir'
- The directory for installing `#include' header files for use with
- compilers other than GCC. This should normally be `/usr/include'.
- (If you are using Autoconf, you can write it as `@oldincludedir@'.)
-
- The Makefile commands should check whether the value of
- `oldincludedir' is empty. If it is, they should not try to use
- it; they should cancel the second installation of the header files.
-
- A package should not replace an existing header in this directory
- unless the header came from the same package. Thus, if your Foo
- package provides a header file `foo.h', then it should install the
- header file in the `oldincludedir' directory if either (1) there
- is no `foo.h' there or (2) the `foo.h' that exists came from the
- Foo package.
-
- To tell whether `foo.h' came from the Foo package, put a magic
- string in the file--part of a comment--and `grep' for that string.
-
- Unix-style man pages are installed in one of the following:
-
-`mandir'
- The top-level directory for installing the man pages (if any) for
- this package. It will normally be `/usr/local/man', but you should
- write it as `$(prefix)/man'. (If you are using Autoconf, write it
- as `@mandir@'.)
-
-`man1dir'
- The directory for installing section 1 man pages. Write it as
- `$(mandir)/man1'.
-
-`man2dir'
- The directory for installing section 2 man pages. Write it as
- `$(mandir)/man2'
-
-`...'
- *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.*
-
-`manext'
- The file name extension for the installed man page. This should
- contain a period followed by the appropriate digit; it should
- normally be `.1'.
-
-`man1ext'
- The file name extension for installed section 1 man pages.
-
-`man2ext'
- The file name extension for installed section 2 man pages.
-
-`...'
- Use these names instead of `manext' if the package needs to
- install man pages in more than one section of the manual.
-
- And finally, you should set the following variable:
-
-`srcdir'
- The directory for the sources being compiled. The value of this
- variable is normally inserted by the `configure' shell script.
- (If you are using Autconf, use `srcdir = @srcdir@'.)
-
- For example:
-
- # 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.
- libexecdir = $(exec_prefix)/libexec
- # Where to put the Info files.
- infodir = $(prefix)/info
-
- 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 `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.