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2774 lines
114 KiB
Plaintext
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This is configure.info, produced by makeinfo version 4.8 from
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./configure.texi.
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INFO-DIR-SECTION GNU admin
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START-INFO-DIR-ENTRY
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* configure: (configure). The GNU configure and build system
|
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END-INFO-DIR-ENTRY
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This file documents the GNU configure and build system.
|
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Copyright (C) 1998 Cygnus Solutions.
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Permission is granted to make and distribute verbatim copies of this
|
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manual provided the copyright notice and this permission notice are
|
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preserved on all copies.
|
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|
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|
Permission is granted to copy and distribute modified versions of
|
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|
this manual under the conditions for verbatim copying, provided that
|
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|
the entire resulting derived work is distributed under the terms of a
|
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|
permission notice identical to this one.
|
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|
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|
Permission is granted to copy and distribute translations of this
|
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|
manual into another language, under the above conditions for modified
|
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|
versions, except that this permission notice may be stated in a
|
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|
translation approved by the Foundation.
|
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File: configure.info, Node: Top, Next: Introduction, Up: (dir)
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GNU configure and build system
|
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|
******************************
|
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|
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|
The GNU configure and build system.
|
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|
|
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* Menu:
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|
|
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* Introduction:: Introduction.
|
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* Getting Started:: Getting Started.
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|
* Files:: Files.
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* Configuration Names:: Configuration Names.
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|
* Cross Compilation Tools:: Cross Compilation Tools.
|
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|
* Canadian Cross:: Canadian Cross.
|
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|
* Cygnus Configure:: Cygnus Configure.
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|
* Multilibs:: Multilibs.
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|
* FAQ:: Frequently Asked Questions.
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|
* Index:: Index.
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File: configure.info, Node: Introduction, Next: Getting Started, Prev: Top, Up: Top
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1 Introduction
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|
**************
|
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|
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|
This document describes the GNU configure and build systems. It
|
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|
describes how autoconf, automake, libtool, and make fit together. It
|
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|
also includes a discussion of the older Cygnus configure system.
|
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|
|
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|
This document does not describe in detail how to use each of the
|
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|
tools; see the respective manuals for that. Instead, it describes
|
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|
which files the developer must write, which files are machine generated
|
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|
and how they are generated, and where certain common problems should be
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|
addressed.
|
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|
|
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|
This document draws on several sources, including the autoconf
|
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|
manual by David MacKenzie (*note autoconf overview: (autoconf)Top.),
|
|||
|
the automake manual by David MacKenzie and Tom Tromey (*note automake
|
|||
|
overview: (automake)Top.), the libtool manual by Gordon Matzigkeit
|
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|
(*note libtool overview: (libtool)Top.), and the Cygnus configure
|
|||
|
manual by K. Richard Pixley.
|
|||
|
|
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|
* Menu:
|
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|
|
|||
|
* Goals:: Goals.
|
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|
* Tools:: The tools.
|
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|
* History:: History.
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|
* Building:: Building.
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|
File: configure.info, Node: Goals, Next: Tools, Up: Introduction
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|
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|
1.1 Goals
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|
=========
|
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|
|
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|
The GNU configure and build system has two main goals.
|
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|
|
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|
The first is to simplify the development of portable programs. The
|
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|
system permits the developer to concentrate on writing the program,
|
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|
simplifying many details of portability across Unix and even Windows
|
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|
systems, and permitting the developer to describe how to build the
|
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|
program using simple rules rather than complex Makefiles.
|
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|
|
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|
The second is to simplify the building of programs distributed as
|
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|
source code. All programs are built using a simple, standardized, two
|
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|
step process. The program builder need not install any special tools in
|
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|
order to build the program.
|
|||
|
|
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|
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|
File: configure.info, Node: Tools, Next: History, Prev: Goals, Up: Introduction
|
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|
|
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|
1.2 Tools
|
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|
=========
|
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|
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|
The GNU configure and build system is comprised of several different
|
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|
tools. Program developers must build and install all of these tools.
|
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|
|
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|
People who just want to build programs from distributed sources
|
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|
normally do not need any special tools beyond a Unix shell, a make
|
|||
|
program, and a C compiler.
|
|||
|
|
|||
|
autoconf
|
|||
|
provides a general portability framework, based on testing the
|
|||
|
features of the host system at build time.
|
|||
|
|
|||
|
automake
|
|||
|
a system for describing how to build a program, permitting the
|
|||
|
developer to write a simplified `Makefile'.
|
|||
|
|
|||
|
libtool
|
|||
|
a standardized approach to building shared libraries.
|
|||
|
|
|||
|
gettext
|
|||
|
provides a framework for translation of text messages into other
|
|||
|
languages; not really discussed in this document.
|
|||
|
|
|||
|
m4
|
|||
|
autoconf requires the GNU version of m4; the standard Unix m4 does
|
|||
|
not suffice.
|
|||
|
|
|||
|
perl
|
|||
|
automake requires perl.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: History, Next: Building, Prev: Tools, Up: Introduction
|
|||
|
|
|||
|
1.3 History
|
|||
|
===========
|
|||
|
|
|||
|
This is a very brief and probably inaccurate history.
|
|||
|
|
|||
|
As the number of Unix variants increased during the 1980s, it became
|
|||
|
harder to write programs which could run on all variants. While it was
|
|||
|
often possible to use `#ifdef' to identify particular systems,
|
|||
|
developers frequently did not have access to every system, and the
|
|||
|
characteristics of some systems changed from version to version.
|
|||
|
|
|||
|
By 1992, at least three different approaches had been developed:
|
|||
|
* The Metaconfig program, by Larry Wall, Harlan Stenn, and Raphael
|
|||
|
Manfredi.
|
|||
|
|
|||
|
* The Cygnus configure script, by K. Richard Pixley, and the gcc
|
|||
|
configure script, by Richard Stallman. These use essentially the
|
|||
|
same approach, and the developers communicated regularly.
|
|||
|
|
|||
|
* The autoconf program, by David MacKenzie.
|
|||
|
|
|||
|
The Metaconfig program is still used for Perl and a few other
|
|||
|
programs. It is part of the Dist package. I do not know if it is
|
|||
|
being developed.
|
|||
|
|
|||
|
In 1994, David MacKenzie and others modified autoconf to incorporate
|
|||
|
all the features of Cygnus configure. Since then, there has been a
|
|||
|
slow but steady conversion of GNU programs from Cygnus configure to
|
|||
|
autoconf. gcc has been converted, eliminating the gcc configure script.
|
|||
|
|
|||
|
GNU autoconf was regularly maintained until late 1996. As of this
|
|||
|
writing in June, 1998, it has no public maintainer.
|
|||
|
|
|||
|
Most programs are built using the make program, which requires the
|
|||
|
developer to write Makefiles describing how to build the programs.
|
|||
|
Since most programs are built in pretty much the same way, this led to a
|
|||
|
lot of duplication.
|
|||
|
|
|||
|
The X Window system is built using the imake tool, which uses a
|
|||
|
database of rules to eliminate the duplication. However, building a
|
|||
|
tool which was developed using imake requires that the builder have
|
|||
|
imake installed, violating one of the goals of the GNU system.
|
|||
|
|
|||
|
The new BSD make provides a standard library of Makefile fragments,
|
|||
|
which permits developers to write very simple Makefiles. However, this
|
|||
|
requires that the builder install the new BSD make program.
|
|||
|
|
|||
|
In 1994, David MacKenzie wrote the first version of automake, which
|
|||
|
permitted writing a simple build description which was converted into a
|
|||
|
Makefile which could be used by the standard make program. In 1995, Tom
|
|||
|
Tromey completely rewrote automake in Perl, and he continues to enhance
|
|||
|
it.
|
|||
|
|
|||
|
Various free packages built libraries, and by around 1995 several
|
|||
|
included support to build shared libraries on various platforms.
|
|||
|
However, there was no consistent approach. In early 1996, Gordon
|
|||
|
Matzigkeit began working on libtool, which provided a standardized
|
|||
|
approach to building shared libraries. This was integrated into
|
|||
|
automake from the start.
|
|||
|
|
|||
|
The development of automake and libtool was driven by the GNITS
|
|||
|
project, a group of GNU maintainers who designed standardized tools to
|
|||
|
help meet the GNU coding standards.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Building, Prev: History, Up: Introduction
|
|||
|
|
|||
|
1.4 Building
|
|||
|
============
|
|||
|
|
|||
|
Most readers of this document should already know how to build a tool by
|
|||
|
running `configure' and `make'. This section may serve as a quick
|
|||
|
introduction or reminder.
|
|||
|
|
|||
|
Building a tool is normally as simple as running `configure'
|
|||
|
followed by `make'. You should normally run `configure' from an empty
|
|||
|
directory, using some path to refer to the `configure' script in the
|
|||
|
source directory. The directory in which you run `configure' is called
|
|||
|
the "object directory".
|
|||
|
|
|||
|
In order to use a object directory which is different from the source
|
|||
|
directory, you must be using the GNU version of `make', which has the
|
|||
|
required `VPATH' support. Despite this restriction, using a different
|
|||
|
object directory is highly recommended:
|
|||
|
* It keeps the files generated during the build from cluttering up
|
|||
|
your sources.
|
|||
|
|
|||
|
* It permits you to remove the built files by simply removing the
|
|||
|
entire build directory.
|
|||
|
|
|||
|
* It permits you to build from the same sources with several sets of
|
|||
|
configure options simultaneously.
|
|||
|
|
|||
|
If you don't have GNU `make', you will have to run `configure' in
|
|||
|
the source directory. All GNU packages should support this; in
|
|||
|
particular, GNU packages should not assume the presence of GNU `make'.
|
|||
|
|
|||
|
After running `configure', you can build the tools by running `make'.
|
|||
|
|
|||
|
To install the tools, run `make install'. Installing the tools will
|
|||
|
copy the programs and any required support files to the "installation
|
|||
|
directory". The location of the installation directory is controlled
|
|||
|
by `configure' options, as described below.
|
|||
|
|
|||
|
In the Cygnus tree at present, the info files are built and
|
|||
|
installed as a separate step. To build them, run `make info'. To
|
|||
|
install them, run `make install-info'. The equivalent html files are
|
|||
|
also built and installed in a separate step. To build the html files,
|
|||
|
run `make html'. To install the html files run `make install-html'.
|
|||
|
|
|||
|
All `configure' scripts support a wide variety of options. The most
|
|||
|
interesting ones are `--with' and `--enable' options which are
|
|||
|
generally specific to particular tools. You can usually use the
|
|||
|
`--help' option to get a list of interesting options for a particular
|
|||
|
configure script.
|
|||
|
|
|||
|
The only generic options you are likely to use are the `--prefix'
|
|||
|
and `--exec-prefix' options. These options are used to specify the
|
|||
|
installation directory.
|
|||
|
|
|||
|
The directory named by the `--prefix' option will hold machine
|
|||
|
independent files such as info files.
|
|||
|
|
|||
|
The directory named by the `--exec-prefix' option, which is normally
|
|||
|
a subdirectory of the `--prefix' directory, will hold machine dependent
|
|||
|
files such as executables.
|
|||
|
|
|||
|
The default for `--prefix' is `/usr/local'. The default for
|
|||
|
`--exec-prefix' is the value used for `--prefix'.
|
|||
|
|
|||
|
The convention used in Cygnus releases is to use a `--prefix' option
|
|||
|
of `/usr/cygnus/RELEASE', where RELEASE is the name of the release, and
|
|||
|
to use a `--exec-prefix' option of `/usr/cygnus/RELEASE/H-HOST', where
|
|||
|
HOST is the configuration name of the host system (*note Configuration
|
|||
|
Names::).
|
|||
|
|
|||
|
Do not use either the source or the object directory as the
|
|||
|
installation directory. That will just lead to confusion.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Getting Started, Next: Files, Prev: Introduction, Up: Top
|
|||
|
|
|||
|
2 Getting Started
|
|||
|
*****************
|
|||
|
|
|||
|
To start using the GNU configure and build system with your software
|
|||
|
package, you must write three files, and you must run some tools to
|
|||
|
manually generate additional files.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Write configure.in:: Write configure.in.
|
|||
|
* Write Makefile.am:: Write Makefile.am.
|
|||
|
* Write acconfig.h:: Write acconfig.h.
|
|||
|
* Generate files:: Generate files.
|
|||
|
* Getting Started Example:: Example.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Write configure.in, Next: Write Makefile.am, Up: Getting Started
|
|||
|
|
|||
|
2.1 Write configure.in
|
|||
|
======================
|
|||
|
|
|||
|
You must first write the file `configure.in'. This is an autoconf
|
|||
|
input file, and the autoconf manual describes in detail what this file
|
|||
|
should look like.
|
|||
|
|
|||
|
You will write tests in your `configure.in' file to check for
|
|||
|
conditions that may change from one system to another, such as the
|
|||
|
presence of particular header files or functions.
|
|||
|
|
|||
|
For example, not all systems support the `gettimeofday' function.
|
|||
|
If you want to use the `gettimeofday' function when it is available,
|
|||
|
and to use some other function when it is not, you would check for this
|
|||
|
by putting `AC_CHECK_FUNCS(gettimeofday)' in `configure.in'.
|
|||
|
|
|||
|
When the configure script is run at build time, this will arrange to
|
|||
|
define the preprocessor macro `HAVE_GETTIMEOFDAY' to the value 1 if the
|
|||
|
`gettimeofday' function is available, and to not define the macro at
|
|||
|
all if the function is not available. Your code can then use `#ifdef'
|
|||
|
to test whether it is safe to call `gettimeofday'.
|
|||
|
|
|||
|
If you have an existing body of code, the `autoscan' program may
|
|||
|
help identify potential portability problems, and hence configure tests
|
|||
|
that you will want to use. *Note Invoking autoscan: (autoconf)Invoking
|
|||
|
autoscan.
|
|||
|
|
|||
|
Another handy tool for an existing body of code is `ifnames'. This
|
|||
|
will show you all the preprocessor conditionals that the code already
|
|||
|
uses. *Note Invoking ifnames: (autoconf)Invoking ifnames.
|
|||
|
|
|||
|
Besides the portability tests which are specific to your particular
|
|||
|
package, every `configure.in' file should contain the following macros.
|
|||
|
|
|||
|
`AC_INIT'
|
|||
|
This macro takes a single argument, which is the name of a file in
|
|||
|
your package. For example, `AC_INIT(foo.c)'.
|
|||
|
|
|||
|
`AC_PREREQ(VERSION)'
|
|||
|
This macro is optional. It may be used to indicate the version of
|
|||
|
`autoconf' that you are using. This will prevent users from
|
|||
|
running an earlier version of `autoconf' and perhaps getting an
|
|||
|
invalid `configure' script. For example, `AC_PREREQ(2.12)'.
|
|||
|
|
|||
|
`AM_INIT_AUTOMAKE'
|
|||
|
This macro takes two arguments: the name of the package, and a
|
|||
|
version number. For example, `AM_INIT_AUTOMAKE(foo, 1.0)'. (This
|
|||
|
macro is not needed if you are not using automake).
|
|||
|
|
|||
|
`AM_CONFIG_HEADER'
|
|||
|
This macro names the header file which will hold the preprocessor
|
|||
|
macro definitions at run time. Normally this should be
|
|||
|
`config.h'. Your sources would then use `#include "config.h"' to
|
|||
|
include it.
|
|||
|
|
|||
|
This macro may optionally name the input file for that header
|
|||
|
file; by default, this is `config.h.in', but that file name works
|
|||
|
poorly on DOS filesystems. Therefore, it is often better to name
|
|||
|
it explicitly as `config.in'.
|
|||
|
|
|||
|
This is what you should normally put in `configure.in':
|
|||
|
AM_CONFIG_HEADER(config.h:config.in)
|
|||
|
|
|||
|
(If you are not using automake, use `AC_CONFIG_HEADER' rather than
|
|||
|
`AM_CONFIG_HEADER').
|
|||
|
|
|||
|
`AM_MAINTAINER_MODE'
|
|||
|
This macro always appears in Cygnus configure scripts. Other
|
|||
|
programs may or may not use it.
|
|||
|
|
|||
|
If this macro is used, the `--enable-maintainer-mode' option is
|
|||
|
required to enable automatic rebuilding of generated files used by
|
|||
|
the configure system. This of course requires that developers be
|
|||
|
aware of, and use, that option.
|
|||
|
|
|||
|
If this macro is not used, then the generated files will always be
|
|||
|
rebuilt automatically. This will cause problems if the wrong
|
|||
|
versions of autoconf, automake, or others are in the builder's
|
|||
|
`PATH'.
|
|||
|
|
|||
|
(If you are not using automake, you do not need to use this macro).
|
|||
|
|
|||
|
`AC_EXEEXT'
|
|||
|
Either this macro or `AM_EXEEXT' always appears in Cygnus configure
|
|||
|
files. Other programs may or may not use one of them.
|
|||
|
|
|||
|
This macro looks for the executable suffix used on the host
|
|||
|
system. On Unix systems, this is the empty string. On Windows
|
|||
|
systems, this is `.exe'. This macro directs automake to use the
|
|||
|
executable suffix as appropriate when creating programs. This
|
|||
|
macro does not take any arguments.
|
|||
|
|
|||
|
The `AC_EXEEXT' form is new, and is part of a Cygnus patch to
|
|||
|
autoconf to support compiling with Visual C++. Older programs use
|
|||
|
`AM_EXEEXT' instead.
|
|||
|
|
|||
|
(Programs which do not use automake use neither `AC_EXEEXT' nor
|
|||
|
`AM_EXEEXT').
|
|||
|
|
|||
|
`AC_PROG_CC'
|
|||
|
If you are writing C code, you will normally want to use this
|
|||
|
macro. It locates the C compiler to use. It does not take any
|
|||
|
arguments.
|
|||
|
|
|||
|
However, if this `configure.in' file is for a library which is to
|
|||
|
be compiled by a cross compiler which may not fully work, then you
|
|||
|
will not want to use `AC_PROG_CC'. Instead, you will want to use a
|
|||
|
variant which does not call the macro `AC_PROG_CC_WORKS'. Examples
|
|||
|
can be found in various `configure.in' files for libraries that are
|
|||
|
compiled with cross compilers, such as libiberty or libgloss.
|
|||
|
This is essentially a bug in autoconf, and there will probably be
|
|||
|
a better workaround at some point.
|
|||
|
|
|||
|
`AC_PROG_CXX'
|
|||
|
If you are writing C++ code, you will want to use this macro. It
|
|||
|
locates the C++ compiler to use. It does not take any arguments.
|
|||
|
The same cross compiler comments apply as for `AC_PROG_CC'.
|
|||
|
|
|||
|
`AM_PROG_LIBTOOL'
|
|||
|
If you want to build libraries, and you want to permit them to be
|
|||
|
shared, or you want to link against libraries which were built
|
|||
|
using libtool, then you will need this macro. This macro is
|
|||
|
required in order to use libtool.
|
|||
|
|
|||
|
By default, this will cause all libraries to be built as shared
|
|||
|
libraries. To prevent this-to change the default-use
|
|||
|
`AM_DISABLE_SHARED' before `AM_PROG_LIBTOOL'. The configure
|
|||
|
options `--enable-shared' and `--disable-shared' may be used to
|
|||
|
override the default at build time.
|
|||
|
|
|||
|
`AC_DEFINE(_GNU_SOURCE)'
|
|||
|
GNU packages should normally include this line before any other
|
|||
|
feature tests. This defines the macro `_GNU_SOURCE' when
|
|||
|
compiling, which directs the libc header files to provide the
|
|||
|
standard GNU system interfaces including all GNU extensions. If
|
|||
|
this macro is not defined, certain GNU extensions may not be
|
|||
|
available.
|
|||
|
|
|||
|
`AC_OUTPUT'
|
|||
|
This macro takes a list of file names which the configure process
|
|||
|
should produce. This is normally a list of one or more `Makefile'
|
|||
|
files in different directories. If your package lives entirely in
|
|||
|
a single directory, you would use simply `AC_OUTPUT(Makefile)'.
|
|||
|
If you also have, for example, a `lib' subdirectory, you would use
|
|||
|
`AC_OUTPUT(Makefile lib/Makefile)'.
|
|||
|
|
|||
|
If you want to use locally defined macros in your `configure.in'
|
|||
|
file, then you will need to write a `acinclude.m4' file which defines
|
|||
|
them (if not using automake, this file is called `aclocal.m4').
|
|||
|
Alternatively, you can put separate macros in an `m4' subdirectory, and
|
|||
|
put `ACLOCAL_AMFLAGS = -I m4' in your `Makefile.am' file so that the
|
|||
|
`aclocal' program will be able to find them.
|
|||
|
|
|||
|
The different macro prefixes indicate which tool defines the macro.
|
|||
|
Macros which start with `AC_' are part of autoconf. Macros which start
|
|||
|
with `AM_' are provided by automake or libtool.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Write Makefile.am, Next: Write acconfig.h, Prev: Write configure.in, Up: Getting Started
|
|||
|
|
|||
|
2.2 Write Makefile.am
|
|||
|
=====================
|
|||
|
|
|||
|
You must write the file `Makefile.am'. This is an automake input file,
|
|||
|
and the automake manual describes in detail what this file should look
|
|||
|
like.
|
|||
|
|
|||
|
The automake commands in `Makefile.am' mostly look like variable
|
|||
|
assignments in a `Makefile'. automake recognizes special variable
|
|||
|
names, and automatically add make rules to the output as needed.
|
|||
|
|
|||
|
There will be one `Makefile.am' file for each directory in your
|
|||
|
package. For each directory with subdirectories, the `Makefile.am'
|
|||
|
file should contain the line
|
|||
|
SUBDIRS = DIR DIR ...
|
|||
|
where each DIR is the name of a subdirectory.
|
|||
|
|
|||
|
For each `Makefile.am', there should be a corresponding `Makefile'
|
|||
|
in the `AC_OUTPUT' macro in `configure.in'.
|
|||
|
|
|||
|
Every `Makefile.am' written at Cygnus should contain the line
|
|||
|
AUTOMAKE_OPTIONS = cygnus
|
|||
|
This puts automake into Cygnus mode. See the automake manual for
|
|||
|
details.
|
|||
|
|
|||
|
You may to include the version number of `automake' that you are
|
|||
|
using on the `AUTOMAKE_OPTIONS' line. For example,
|
|||
|
AUTOMAKE_OPTIONS = cygnus 1.3
|
|||
|
This will prevent users from running an earlier version of
|
|||
|
`automake' and perhaps getting an invalid `Makefile.in'.
|
|||
|
|
|||
|
If your package builds a program, then in the directory where that
|
|||
|
program is built you will normally want a line like
|
|||
|
bin_PROGRAMS = PROGRAM
|
|||
|
where PROGRAM is the name of the program. You will then want a line
|
|||
|
like
|
|||
|
PROGRAM_SOURCES = FILE FILE ...
|
|||
|
where each FILE is the name of a source file to link into the
|
|||
|
program (e.g., `foo.c').
|
|||
|
|
|||
|
If your package builds a library, and you do not want the library to
|
|||
|
ever be built as a shared library, then in the directory where that
|
|||
|
library is built you will normally want a line like
|
|||
|
lib_LIBRARIES = libNAME.a
|
|||
|
where `libNAME.a' is the name of the library. You will then want a
|
|||
|
line like
|
|||
|
libNAME_a_SOURCES = FILE FILE ...
|
|||
|
where each FILE is the name of a source file to add to the library.
|
|||
|
|
|||
|
If your package builds a library, and you want to permit building the
|
|||
|
library as a shared library, then in the directory where that library is
|
|||
|
built you will normally want a line like
|
|||
|
lib_LTLIBRARIES = libNAME.la
|
|||
|
The use of `LTLIBRARIES', and the `.la' extension, indicate a
|
|||
|
library to be built using libtool. As usual, you will then want a line
|
|||
|
like
|
|||
|
libNAME_la_SOURCES = FILE FILE ...
|
|||
|
|
|||
|
The strings `bin' and `lib' that appear above in `bin_PROGRAMS' and
|
|||
|
`lib_LIBRARIES' are not arbitrary. They refer to particular
|
|||
|
directories, which may be set by the `--bindir' and `--libdir' options
|
|||
|
to `configure'. If those options are not used, the default values are
|
|||
|
based on the `--prefix' or `--exec-prefix' options to `configure'. It
|
|||
|
is possible to use other names if the program or library should be
|
|||
|
installed in some other directory.
|
|||
|
|
|||
|
The `Makefile.am' file may also contain almost anything that may
|
|||
|
appear in a normal `Makefile'. automake also supports many other
|
|||
|
special variables, as well as conditionals.
|
|||
|
|
|||
|
See the automake manual for more information.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Write acconfig.h, Next: Generate files, Prev: Write Makefile.am, Up: Getting Started
|
|||
|
|
|||
|
2.3 Write acconfig.h
|
|||
|
====================
|
|||
|
|
|||
|
If you are generating a portability header file, (i.e., you are using
|
|||
|
`AM_CONFIG_HEADER' in `configure.in'), then you will have to write a
|
|||
|
`acconfig.h' file. It will have to contain the following lines.
|
|||
|
|
|||
|
/* Name of package. */
|
|||
|
#undef PACKAGE
|
|||
|
|
|||
|
/* Version of package. */
|
|||
|
#undef VERSION
|
|||
|
|
|||
|
This requirement is really a bug in the system, and the requirement
|
|||
|
may be eliminated at some later date.
|
|||
|
|
|||
|
The `acconfig.h' file will also similar comment and `#undef' lines
|
|||
|
for any unusual macros in the `configure.in' file, including any macro
|
|||
|
which appears in a `AC_DEFINE' macro.
|
|||
|
|
|||
|
In particular, if you are writing a GNU package and therefore include
|
|||
|
`AC_DEFINE(_GNU_SOURCE)' in `configure.in' as suggested above, you will
|
|||
|
need lines like this in `acconfig.h':
|
|||
|
/* Enable GNU extensions. */
|
|||
|
#undef _GNU_SOURCE
|
|||
|
|
|||
|
Normally the `autoheader' program will inform you of any such
|
|||
|
requirements by printing an error message when it is run. However, if
|
|||
|
you do anything particular odd in your `configure.in' file, you will
|
|||
|
have to make sure that the right entries appear in `acconfig.h', since
|
|||
|
otherwise the results of the tests may not be available in the
|
|||
|
`config.h' file which your code will use.
|
|||
|
|
|||
|
(Thee `PACKAGE' and `VERSION' lines are not required if you are not
|
|||
|
using automake, and in that case you may not need a `acconfig.h' file
|
|||
|
at all).
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Generate files, Next: Getting Started Example, Prev: Write acconfig.h, Up: Getting Started
|
|||
|
|
|||
|
2.4 Generate files
|
|||
|
==================
|
|||
|
|
|||
|
Once you have written `configure.in', `Makefile.am', `acconfig.h', and
|
|||
|
possibly `acinclude.m4', you must use autoconf and automake programs to
|
|||
|
produce the first versions of the generated files. This is done by
|
|||
|
executing the following sequence of commands.
|
|||
|
|
|||
|
aclocal
|
|||
|
autoconf
|
|||
|
autoheader
|
|||
|
automake
|
|||
|
|
|||
|
The `aclocal' and `automake' commands are part of the automake
|
|||
|
package, and the `autoconf' and `autoheader' commands are part of the
|
|||
|
autoconf package.
|
|||
|
|
|||
|
If you are using a `m4' subdirectory for your macros, you will need
|
|||
|
to use the `-I m4' option when you run `aclocal'.
|
|||
|
|
|||
|
If you are not using the Cygnus tree, use the `-a' option when
|
|||
|
running `automake' command in order to copy the required support files
|
|||
|
into your source directory.
|
|||
|
|
|||
|
If you are using libtool, you must build and install the libtool
|
|||
|
package with the same `--prefix' and `--exec-prefix' options as you
|
|||
|
used with the autoconf and automake packages. You must do this before
|
|||
|
running any of the above commands. If you are not using the Cygnus
|
|||
|
tree, you will need to run the `libtoolize' program to copy the libtool
|
|||
|
support files into your directory.
|
|||
|
|
|||
|
Once you have managed to run these commands without getting any
|
|||
|
errors, you should create a new empty directory, and run the `configure'
|
|||
|
script which will have been created by `autoconf' with the
|
|||
|
`--enable-maintainer-mode' option. This will give you a set of
|
|||
|
Makefiles which will include rules to automatically rebuild all the
|
|||
|
generated files.
|
|||
|
|
|||
|
After doing that, whenever you have changed some of the input files
|
|||
|
and want to regenerated the other files, go to your object directory
|
|||
|
and run `make'. Doing this is more reliable than trying to rebuild the
|
|||
|
files manually, because there are complex order dependencies and it is
|
|||
|
easy to forget something.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Getting Started Example, Prev: Generate files, Up: Getting Started
|
|||
|
|
|||
|
2.5 Example
|
|||
|
===========
|
|||
|
|
|||
|
Let's consider a trivial example.
|
|||
|
|
|||
|
Suppose we want to write a simple version of `touch'. Our program,
|
|||
|
which we will call `poke', will take a single file name argument, and
|
|||
|
use the `utime' system call to set the modification and access times of
|
|||
|
the file to the current time. We want this program to be highly
|
|||
|
portable.
|
|||
|
|
|||
|
We'll first see what this looks like without using autoconf and
|
|||
|
automake, and then see what it looks like with them.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Getting Started Example 1:: First Try.
|
|||
|
* Getting Started Example 2:: Second Try.
|
|||
|
* Getting Started Example 3:: Third Try.
|
|||
|
* Generate Files in Example:: Generate Files.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Getting Started Example 1, Next: Getting Started Example 2, Up: Getting Started Example
|
|||
|
|
|||
|
2.5.1 First Try
|
|||
|
---------------
|
|||
|
|
|||
|
Here is our first try at `poke.c'. Note that we've written it without
|
|||
|
ANSI/ISO C prototypes, since we want it to be highly portable.
|
|||
|
|
|||
|
#include <stdio.h>
|
|||
|
#include <stdlib.h>
|
|||
|
#include <sys/types.h>
|
|||
|
#include <utime.h>
|
|||
|
|
|||
|
int
|
|||
|
main (argc, argv)
|
|||
|
int argc;
|
|||
|
char **argv;
|
|||
|
{
|
|||
|
if (argc != 2)
|
|||
|
{
|
|||
|
fprintf (stderr, "Usage: poke file\n");
|
|||
|
exit (1);
|
|||
|
}
|
|||
|
|
|||
|
if (utime (argv[1], NULL) < 0)
|
|||
|
{
|
|||
|
perror ("utime");
|
|||
|
exit (1);
|
|||
|
}
|
|||
|
|
|||
|
exit (0);
|
|||
|
}
|
|||
|
|
|||
|
We also write a simple `Makefile'.
|
|||
|
|
|||
|
CC = gcc
|
|||
|
CFLAGS = -g -O2
|
|||
|
|
|||
|
all: poke
|
|||
|
|
|||
|
poke: poke.o
|
|||
|
$(CC) -o poke $(CFLAGS) $(LDFLAGS) poke.o
|
|||
|
|
|||
|
So far, so good.
|
|||
|
|
|||
|
Unfortunately, there are a few problems.
|
|||
|
|
|||
|
On older Unix systems derived from BSD 4.3, the `utime' system call
|
|||
|
does not accept a second argument of `NULL'. On those systems, we need
|
|||
|
to pass a pointer to `struct utimbuf' structure. Unfortunately, even
|
|||
|
older systems don't define that structure; on those systems, we need to
|
|||
|
pass an array of two `long' values.
|
|||
|
|
|||
|
The header file `stdlib.h' was invented by ANSI C, and older systems
|
|||
|
don't have a copy. We included it above to get a declaration of `exit'.
|
|||
|
|
|||
|
We can find some of these portability problems by running
|
|||
|
`autoscan', which will create a `configure.scan' file which we can use
|
|||
|
as a prototype for our `configure.in' file. I won't show the output,
|
|||
|
but it will notice the potential problems with `utime' and `stdlib.h'.
|
|||
|
|
|||
|
In our `Makefile', we don't provide any way to install the program.
|
|||
|
This doesn't matter much for such a simple example, but a real program
|
|||
|
will need an `install' target. For that matter, we will also want a
|
|||
|
`clean' target.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Getting Started Example 2, Next: Getting Started Example 3, Prev: Getting Started Example 1, Up: Getting Started Example
|
|||
|
|
|||
|
2.5.2 Second Try
|
|||
|
----------------
|
|||
|
|
|||
|
Here is our second try at this program.
|
|||
|
|
|||
|
We modify `poke.c' to use preprocessor macros to control what
|
|||
|
features are available. (I've cheated a bit by using the same macro
|
|||
|
names which autoconf will use).
|
|||
|
|
|||
|
#include <stdio.h>
|
|||
|
|
|||
|
#ifdef STDC_HEADERS
|
|||
|
#include <stdlib.h>
|
|||
|
#endif
|
|||
|
|
|||
|
#include <sys/types.h>
|
|||
|
|
|||
|
#ifdef HAVE_UTIME_H
|
|||
|
#include <utime.h>
|
|||
|
#endif
|
|||
|
|
|||
|
#ifndef HAVE_UTIME_NULL
|
|||
|
|
|||
|
#include <time.h>
|
|||
|
|
|||
|
#ifndef HAVE_STRUCT_UTIMBUF
|
|||
|
|
|||
|
struct utimbuf
|
|||
|
{
|
|||
|
long actime;
|
|||
|
long modtime;
|
|||
|
};
|
|||
|
|
|||
|
#endif
|
|||
|
|
|||
|
static int
|
|||
|
utime_now (file)
|
|||
|
char *file;
|
|||
|
{
|
|||
|
struct utimbuf now;
|
|||
|
|
|||
|
now.actime = now.modtime = time (NULL);
|
|||
|
return utime (file, &now);
|
|||
|
}
|
|||
|
|
|||
|
#define utime(f, p) utime_now (f)
|
|||
|
|
|||
|
#endif /* HAVE_UTIME_NULL */
|
|||
|
|
|||
|
int
|
|||
|
main (argc, argv)
|
|||
|
int argc;
|
|||
|
char **argv;
|
|||
|
{
|
|||
|
if (argc != 2)
|
|||
|
{
|
|||
|
fprintf (stderr, "Usage: poke file\n");
|
|||
|
exit (1);
|
|||
|
}
|
|||
|
|
|||
|
if (utime (argv[1], NULL) < 0)
|
|||
|
{
|
|||
|
perror ("utime");
|
|||
|
exit (1);
|
|||
|
}
|
|||
|
|
|||
|
exit (0);
|
|||
|
}
|
|||
|
|
|||
|
Here is the associated `Makefile'. We've added support for the
|
|||
|
preprocessor flags we use. We've also added `install' and `clean'
|
|||
|
targets.
|
|||
|
|
|||
|
# Set this to your installation directory.
|
|||
|
bindir = /usr/local/bin
|
|||
|
|
|||
|
# Uncomment this if you have the standard ANSI/ISO C header files.
|
|||
|
# STDC_HDRS = -DSTDC_HEADERS
|
|||
|
|
|||
|
# Uncomment this if you have utime.h.
|
|||
|
# UTIME_H = -DHAVE_UTIME_H
|
|||
|
|
|||
|
# Uncomment this if utime (FILE, NULL) works on your system.
|
|||
|
# UTIME_NULL = -DHAVE_UTIME_NULL
|
|||
|
|
|||
|
# Uncomment this if struct utimbuf is defined in utime.h.
|
|||
|
# UTIMBUF = -DHAVE_STRUCT_UTIMBUF
|
|||
|
|
|||
|
CC = gcc
|
|||
|
CFLAGS = -g -O2
|
|||
|
|
|||
|
ALL_CFLAGS = $(STDC_HDRS) $(UTIME_H) $(UTIME_NULL) $(UTIMBUF) $(CFLAGS)
|
|||
|
|
|||
|
all: poke
|
|||
|
|
|||
|
poke: poke.o
|
|||
|
$(CC) -o poke $(ALL_CFLAGS) $(LDFLAGS) poke.o
|
|||
|
|
|||
|
.c.o:
|
|||
|
$(CC) -c $(ALL_CFLAGS) poke.c
|
|||
|
|
|||
|
install: poke
|
|||
|
cp poke $(bindir)/poke
|
|||
|
|
|||
|
clean:
|
|||
|
rm poke poke.o
|
|||
|
|
|||
|
Some problems with this approach should be clear.
|
|||
|
|
|||
|
Users who want to compile poke will have to know how `utime' works
|
|||
|
on their systems, so that they can uncomment the `Makefile' correctly.
|
|||
|
|
|||
|
The installation is done using `cp', but many systems have an
|
|||
|
`install' program which may be used, and which supports optional
|
|||
|
features such as stripping debugging information out of the installed
|
|||
|
binary.
|
|||
|
|
|||
|
The use of `Makefile' variables like `CC', `CFLAGS' and `LDFLAGS'
|
|||
|
follows the requirements of the GNU standards. This is convenient for
|
|||
|
all packages, since it reduces surprises for users. However, it is
|
|||
|
easy to get the details wrong, and wind up with a slightly nonstandard
|
|||
|
distribution.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Getting Started Example 3, Next: Generate Files in Example, Prev: Getting Started Example 2, Up: Getting Started Example
|
|||
|
|
|||
|
2.5.3 Third Try
|
|||
|
---------------
|
|||
|
|
|||
|
For our third try at this program, we will write a `configure.in'
|
|||
|
script to discover the configuration features on the host system, rather
|
|||
|
than requiring the user to edit the `Makefile'. We will also write a
|
|||
|
`Makefile.am' rather than a `Makefile'.
|
|||
|
|
|||
|
The only change to `poke.c' is to add a line at the start of the
|
|||
|
file:
|
|||
|
#include "config.h"
|
|||
|
|
|||
|
The new `configure.in' file is as follows.
|
|||
|
|
|||
|
AC_INIT(poke.c)
|
|||
|
AM_INIT_AUTOMAKE(poke, 1.0)
|
|||
|
AM_CONFIG_HEADER(config.h:config.in)
|
|||
|
AC_PROG_CC
|
|||
|
AC_HEADER_STDC
|
|||
|
AC_CHECK_HEADERS(utime.h)
|
|||
|
AC_EGREP_HEADER(utimbuf, utime.h, AC_DEFINE(HAVE_STRUCT_UTIMBUF))
|
|||
|
AC_FUNC_UTIME_NULL
|
|||
|
AC_OUTPUT(Makefile)
|
|||
|
|
|||
|
The first four macros in this file, and the last one, were described
|
|||
|
above; see *Note Write configure.in::. If we omit these macros, then
|
|||
|
when we run `automake' we will get a reminder that we need them.
|
|||
|
|
|||
|
The other macros are standard autoconf macros.
|
|||
|
|
|||
|
`AC_HEADER_STDC'
|
|||
|
Check for standard C headers.
|
|||
|
|
|||
|
`AC_CHECK_HEADERS'
|
|||
|
Check whether a particular header file exists.
|
|||
|
|
|||
|
`AC_EGREP_HEADER'
|
|||
|
Check for a particular string in a particular header file, in this
|
|||
|
case checking for `utimbuf' in `utime.h'.
|
|||
|
|
|||
|
`AC_FUNC_UTIME_NULL'
|
|||
|
Check whether `utime' accepts a NULL second argument to set the
|
|||
|
file change time to the current time.
|
|||
|
|
|||
|
See the autoconf manual for a more complete description.
|
|||
|
|
|||
|
The new `Makefile.am' file is as follows. Note how simple this is
|
|||
|
compared to our earlier `Makefile'.
|
|||
|
|
|||
|
bin_PROGRAMS = poke
|
|||
|
|
|||
|
poke_SOURCES = poke.c
|
|||
|
|
|||
|
This means that we should build a single program name `poke'. It
|
|||
|
should be installed in the binary directory, which we called `bindir'
|
|||
|
earlier. The program `poke' is built from the source file `poke.c'.
|
|||
|
|
|||
|
We must also write a `acconfig.h' file. Besides `PACKAGE' and
|
|||
|
`VERSION', which must be mentioned for all packages which use automake,
|
|||
|
we must include `HAVE_STRUCT_UTIMBUF', since we mentioned it in an
|
|||
|
`AC_DEFINE'.
|
|||
|
|
|||
|
/* Name of package. */
|
|||
|
#undef PACKAGE
|
|||
|
|
|||
|
/* Version of package. */
|
|||
|
#undef VERSION
|
|||
|
|
|||
|
/* Whether utime.h defines struct utimbuf. */
|
|||
|
#undef HAVE_STRUCT_UTIMBUF
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Generate Files in Example, Prev: Getting Started Example 3, Up: Getting Started Example
|
|||
|
|
|||
|
2.5.4 Generate Files
|
|||
|
--------------------
|
|||
|
|
|||
|
We must now generate the other files, using the following commands.
|
|||
|
|
|||
|
aclocal
|
|||
|
autoconf
|
|||
|
autoheader
|
|||
|
automake
|
|||
|
|
|||
|
When we run `autoheader', it will remind us of any macros we forgot
|
|||
|
to add to `acconfig.h'.
|
|||
|
|
|||
|
When we run `automake', it will want to add some files to our
|
|||
|
distribution. It will add them automatically if we use the
|
|||
|
`--add-missing' option.
|
|||
|
|
|||
|
By default, `automake' will run in GNU mode, which means that it
|
|||
|
will want us to create certain additional files; as of this writing, it
|
|||
|
will want `NEWS', `README', `AUTHORS', and `ChangeLog', all of which
|
|||
|
are files which should appear in a standard GNU distribution. We can
|
|||
|
either add those files, or run `automake' with the `--foreign' option.
|
|||
|
|
|||
|
Running these tools will generate the following files, all of which
|
|||
|
are described in the next chapter.
|
|||
|
|
|||
|
* `aclocal.m4'
|
|||
|
|
|||
|
* `configure'
|
|||
|
|
|||
|
* `config.in'
|
|||
|
|
|||
|
* `Makefile.in'
|
|||
|
|
|||
|
* `stamp-h.in'
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Files, Next: Configuration Names, Prev: Getting Started, Up: Top
|
|||
|
|
|||
|
3 Files
|
|||
|
*******
|
|||
|
|
|||
|
As was seen in the previous chapter, the GNU configure and build system
|
|||
|
uses a number of different files. The developer must write a few files.
|
|||
|
The others are generated by various tools.
|
|||
|
|
|||
|
The system is rather flexible, and can be used in many different
|
|||
|
ways. In describing the files that it uses, I will describe the common
|
|||
|
case, and mention some other cases that may arise.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Developer Files:: Developer Files.
|
|||
|
* Build Files:: Build Files.
|
|||
|
* Support Files:: Support Files.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Developer Files, Next: Build Files, Up: Files
|
|||
|
|
|||
|
3.1 Developer Files
|
|||
|
===================
|
|||
|
|
|||
|
This section describes the files written or generated by the developer
|
|||
|
of a package.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Developer Files Picture:: Developer Files Picture.
|
|||
|
* Written Developer Files:: Written Developer Files.
|
|||
|
* Generated Developer Files:: Generated Developer Files.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Developer Files Picture, Next: Written Developer Files, Up: Developer Files
|
|||
|
|
|||
|
3.1.1 Developer Files Picture
|
|||
|
-----------------------------
|
|||
|
|
|||
|
Here is a picture of the files which are written by the developer, the
|
|||
|
generated files which would be included with a complete source
|
|||
|
distribution, and the tools which create those files. The file names
|
|||
|
are plain text and the tool names are enclosed by `*' characters (e.g.,
|
|||
|
`autoheader' is the name of a tool, not the name of a file).
|
|||
|
|
|||
|
acconfig.h configure.in Makefile.am
|
|||
|
| | |
|
|||
|
| --------------+---------------------- |
|
|||
|
| | | | |
|
|||
|
v v | acinclude.m4 | |
|
|||
|
*autoheader* | | v v
|
|||
|
| | v --->*automake*
|
|||
|
v |--->*aclocal* | |
|
|||
|
config.in | | | v
|
|||
|
| v | Makefile.in
|
|||
|
| aclocal.m4---
|
|||
|
| |
|
|||
|
v v
|
|||
|
*autoconf*
|
|||
|
|
|
|||
|
v
|
|||
|
configure
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Written Developer Files, Next: Generated Developer Files, Prev: Developer Files Picture, Up: Developer Files
|
|||
|
|
|||
|
3.1.2 Written Developer Files
|
|||
|
-----------------------------
|
|||
|
|
|||
|
The following files would be written by the developer.
|
|||
|
|
|||
|
`configure.in'
|
|||
|
This is the configuration script. This script contains
|
|||
|
invocations of autoconf macros. It may also contain ordinary
|
|||
|
shell script code. This file will contain feature tests for
|
|||
|
portability issues. The last thing in the file will normally be
|
|||
|
an `AC_OUTPUT' macro listing which files to create when the
|
|||
|
builder runs the configure script. This file is always required
|
|||
|
when using the GNU configure system. *Note Write configure.in::.
|
|||
|
|
|||
|
`Makefile.am'
|
|||
|
This is the automake input file. It describes how the code should
|
|||
|
be built. It consists of definitions of automake variables. It
|
|||
|
may also contain ordinary Makefile targets. This file is only
|
|||
|
needed when using automake (newer tools normally use automake, but
|
|||
|
there are still older tools which have not been converted, in
|
|||
|
which the developer writes `Makefile.in' directly). *Note Write
|
|||
|
Makefile.am::.
|
|||
|
|
|||
|
`acconfig.h'
|
|||
|
When the configure script creates a portability header file, by
|
|||
|
using `AM_CONFIG_HEADER' (or, if not using automake,
|
|||
|
`AC_CONFIG_HEADER'), this file is used to describe macros which are
|
|||
|
not recognized by the `autoheader' command. This is normally a
|
|||
|
fairly uninteresting file, consisting of a collection of `#undef'
|
|||
|
lines with comments. Normally any call to `AC_DEFINE' in
|
|||
|
`configure.in' will require a line in this file. *Note Write
|
|||
|
acconfig.h::.
|
|||
|
|
|||
|
`acinclude.m4'
|
|||
|
This file is not always required. It defines local autoconf
|
|||
|
macros. These macros may then be used in `configure.in'. If you
|
|||
|
don't need any local autoconf macros, then you don't need this
|
|||
|
file at all. In fact, in general, you never need local autoconf
|
|||
|
macros, since you can put everything in `configure.in', but
|
|||
|
sometimes a local macro is convenient.
|
|||
|
|
|||
|
Newer tools may omit `acinclude.m4', and instead use a
|
|||
|
subdirectory, typically named `m4', and define `ACLOCAL_AMFLAGS =
|
|||
|
-I m4' in `Makefile.am' to force `aclocal' to look there for macro
|
|||
|
definitions. The macro definitions are then placed in separate
|
|||
|
files in that directory.
|
|||
|
|
|||
|
The `acinclude.m4' file is only used when using automake; in older
|
|||
|
tools, the developer writes `aclocal.m4' directly, if it is needed.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Generated Developer Files, Prev: Written Developer Files, Up: Developer Files
|
|||
|
|
|||
|
3.1.3 Generated Developer Files
|
|||
|
-------------------------------
|
|||
|
|
|||
|
The following files would be generated by the developer.
|
|||
|
|
|||
|
When using automake, these files are normally not generated manually
|
|||
|
after the first time. Instead, the generated `Makefile' contains rules
|
|||
|
to automatically rebuild the files as required. When
|
|||
|
`AM_MAINTAINER_MODE' is used in `configure.in' (the normal case in
|
|||
|
Cygnus code), the automatic rebuilding rules will only be defined if
|
|||
|
you configure using the `--enable-maintainer-mode' option.
|
|||
|
|
|||
|
When using automatic rebuilding, it is important to ensure that all
|
|||
|
the various tools have been built and installed on your `PATH'. Using
|
|||
|
automatic rebuilding is highly recommended, so much so that I'm not
|
|||
|
going to explain what you have to do if you don't use it.
|
|||
|
|
|||
|
`configure'
|
|||
|
This is the configure script which will be run when building the
|
|||
|
package. This is generated by `autoconf' from `configure.in' and
|
|||
|
`aclocal.m4'. This is a shell script.
|
|||
|
|
|||
|
`Makefile.in'
|
|||
|
This is the file which the configure script will turn into the
|
|||
|
`Makefile' at build time. This file is generated by `automake'
|
|||
|
from `Makefile.am'. If you aren't using automake, you must write
|
|||
|
this file yourself. This file is pretty much a normal `Makefile',
|
|||
|
with some configure substitutions for certain variables.
|
|||
|
|
|||
|
`aclocal.m4'
|
|||
|
This file is created by the `aclocal' program, based on the
|
|||
|
contents of `configure.in' and `acinclude.m4' (or, as noted in the
|
|||
|
description of `acinclude.m4' above, on the contents of an `m4'
|
|||
|
subdirectory). This file contains definitions of autoconf macros
|
|||
|
which `autoconf' will use when generating the file `configure'.
|
|||
|
These autoconf macros may be defined by you in `acinclude.m4' or
|
|||
|
they may be defined by other packages such as automake, libtool or
|
|||
|
gettext. If you aren't using automake, you will normally write
|
|||
|
this file yourself; in that case, if `configure.in' uses only
|
|||
|
standard autoconf macros, this file will not be needed at all.
|
|||
|
|
|||
|
`config.in'
|
|||
|
This file is created by `autoheader' based on `acconfig.h' and
|
|||
|
`configure.in'. At build time, the configure script will define
|
|||
|
some of the macros in it to create `config.h', which may then be
|
|||
|
included by your program. This permits your C code to use
|
|||
|
preprocessor conditionals to change its behaviour based on the
|
|||
|
characteristics of the host system. This file may also be called
|
|||
|
`config.h.in'.
|
|||
|
|
|||
|
`stamp.h-in'
|
|||
|
This rather uninteresting file, which I omitted from the picture,
|
|||
|
is generated by `automake'. It always contains the string
|
|||
|
`timestamp'. It is used as a timestamp file indicating whether
|
|||
|
`config.in' is up to date. Using a timestamp file means that
|
|||
|
`config.in' can be marked as up to date without actually changing
|
|||
|
its modification time. This is useful since `config.in' depends
|
|||
|
upon `configure.in', but it is easy to change `configure.in' in a
|
|||
|
way which does not affect `config.in'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Build Files, Next: Support Files, Prev: Developer Files, Up: Files
|
|||
|
|
|||
|
3.2 Build Files
|
|||
|
===============
|
|||
|
|
|||
|
This section describes the files which are created at configure and
|
|||
|
build time. These are the files which somebody who builds the package
|
|||
|
will see.
|
|||
|
|
|||
|
Of course, the developer will also build the package. The
|
|||
|
distinction between developer files and build files is not that the
|
|||
|
developer does not see the build files, but that somebody who only
|
|||
|
builds the package does not have to worry about the developer files.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Build Files Picture:: Build Files Picture.
|
|||
|
* Build Files Description:: Build Files Description.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Build Files Picture, Next: Build Files Description, Up: Build Files
|
|||
|
|
|||
|
3.2.1 Build Files Picture
|
|||
|
-------------------------
|
|||
|
|
|||
|
Here is a picture of the files which will be created at build time.
|
|||
|
`config.status' is both a created file and a shell script which is run
|
|||
|
to create other files, and the picture attempts to show that.
|
|||
|
|
|||
|
config.in *configure* Makefile.in
|
|||
|
| | |
|
|||
|
| v |
|
|||
|
| config.status |
|
|||
|
| | |
|
|||
|
*config.status*<======+==========>*config.status*
|
|||
|
| |
|
|||
|
v v
|
|||
|
config.h Makefile
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Build Files Description, Prev: Build Files Picture, Up: Build Files
|
|||
|
|
|||
|
3.2.2 Build Files Description
|
|||
|
-----------------------------
|
|||
|
|
|||
|
This is a description of the files which are created at build time.
|
|||
|
|
|||
|
`config.status'
|
|||
|
The first step in building a package is to run the `configure'
|
|||
|
script. The `configure' script will create the file
|
|||
|
`config.status', which is itself a shell script. When you first
|
|||
|
run `configure', it will automatically run `config.status'. An
|
|||
|
`Makefile' derived from an automake generated `Makefile.in' will
|
|||
|
contain rules to automatically run `config.status' again when
|
|||
|
necessary to recreate certain files if their inputs change.
|
|||
|
|
|||
|
`Makefile'
|
|||
|
This is the file which make will read to build the program. The
|
|||
|
`config.status' script will transform `Makefile.in' into
|
|||
|
`Makefile'.
|
|||
|
|
|||
|
`config.h'
|
|||
|
This file defines C preprocessor macros which C code can use to
|
|||
|
adjust its behaviour on different systems. The `config.status'
|
|||
|
script will transform `config.in' into `config.h'.
|
|||
|
|
|||
|
`config.cache'
|
|||
|
This file did not fit neatly into the picture, and I omitted it.
|
|||
|
It is used by the `configure' script to cache results between
|
|||
|
runs. This can be an important speedup. If you modify
|
|||
|
`configure.in' in such a way that the results of old tests should
|
|||
|
change (perhaps you have added a new library to `LDFLAGS'), then
|
|||
|
you will have to remove `config.cache' to force the tests to be
|
|||
|
rerun.
|
|||
|
|
|||
|
The autoconf manual explains how to set up a site specific cache
|
|||
|
file. This can speed up running `configure' scripts on your
|
|||
|
system.
|
|||
|
|
|||
|
`stamp.h'
|
|||
|
This file, which I omitted from the picture, is similar to
|
|||
|
`stamp-h.in'. It is used as a timestamp file indicating whether
|
|||
|
`config.h' is up to date. This is useful since `config.h' depends
|
|||
|
upon `config.status', but it is easy for `config.status' to change
|
|||
|
in a way which does not affect `config.h'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Support Files, Prev: Build Files, Up: Files
|
|||
|
|
|||
|
3.3 Support Files
|
|||
|
=================
|
|||
|
|
|||
|
The GNU configure and build system requires several support files to be
|
|||
|
included with your distribution. You do not normally need to concern
|
|||
|
yourself with these. If you are using the Cygnus tree, most are already
|
|||
|
present. Otherwise, they will be installed with your source by
|
|||
|
`automake' (with the `--add-missing' option) and `libtoolize'.
|
|||
|
|
|||
|
You don't have to put the support files in the top level directory.
|
|||
|
You can put them in a subdirectory, and use the `AC_CONFIG_AUX_DIR'
|
|||
|
macro in `configure.in' to tell `automake' and the `configure' script
|
|||
|
where they are.
|
|||
|
|
|||
|
In this section, I describe the support files, so that you can know
|
|||
|
what they are and why they are there.
|
|||
|
|
|||
|
`ABOUT-NLS'
|
|||
|
Added by automake if you are using gettext. This is a
|
|||
|
documentation file about the gettext project.
|
|||
|
|
|||
|
`ansi2knr.c'
|
|||
|
Used by an automake generated `Makefile' if you put `ansi2knr' in
|
|||
|
`AUTOMAKE_OPTIONS' in `Makefile.am'. This permits compiling ANSI
|
|||
|
C code with a K&R C compiler.
|
|||
|
|
|||
|
`ansi2knr.1'
|
|||
|
The man page which goes with `ansi2knr.c'.
|
|||
|
|
|||
|
`config.guess'
|
|||
|
A shell script which determines the configuration name for the
|
|||
|
system on which it is run.
|
|||
|
|
|||
|
`config.sub'
|
|||
|
A shell script which canonicalizes a configuration name entered by
|
|||
|
a user.
|
|||
|
|
|||
|
`elisp-comp'
|
|||
|
Used to compile Emacs LISP files.
|
|||
|
|
|||
|
`install-sh'
|
|||
|
A shell script which installs a program. This is used if the
|
|||
|
configure script can not find an install binary.
|
|||
|
|
|||
|
`ltconfig'
|
|||
|
Used by libtool. This is a shell script which configures libtool
|
|||
|
for the particular system on which it is used.
|
|||
|
|
|||
|
`ltmain.sh'
|
|||
|
Used by libtool. This is the actual libtool script which is used,
|
|||
|
after it is configured by `ltconfig' to build a library.
|
|||
|
|
|||
|
`mdate-sh'
|
|||
|
A shell script used by an automake generated `Makefile' to pretty
|
|||
|
print the modification time of a file. This is used to maintain
|
|||
|
version numbers for texinfo files.
|
|||
|
|
|||
|
`missing'
|
|||
|
A shell script used if some tool is missing entirely. This is
|
|||
|
used by an automake generated `Makefile' to avoid certain sorts of
|
|||
|
timestamp problems.
|
|||
|
|
|||
|
`mkinstalldirs'
|
|||
|
A shell script which creates a directory, including all parent
|
|||
|
directories. This is used by an automake generated `Makefile'
|
|||
|
during installation.
|
|||
|
|
|||
|
`texinfo.tex'
|
|||
|
Required if you have any texinfo files. This is used when
|
|||
|
converting Texinfo files into DVI using `texi2dvi' and TeX.
|
|||
|
|
|||
|
`ylwrap'
|
|||
|
A shell script used by an automake generated `Makefile' to run
|
|||
|
programs like `bison', `yacc', `flex', and `lex'. These programs
|
|||
|
default to producing output files with a fixed name, and the
|
|||
|
`ylwrap' script runs them in a subdirectory to avoid file name
|
|||
|
conflicts when using a parallel make program.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Configuration Names, Next: Cross Compilation Tools, Prev: Files, Up: Top
|
|||
|
|
|||
|
4 Configuration Names
|
|||
|
*********************
|
|||
|
|
|||
|
The GNU configure system names all systems using a "configuration
|
|||
|
name". All such names used to be triplets (they may now contain four
|
|||
|
parts in certain cases), and the term "configuration triplet" is still
|
|||
|
seen.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Configuration Name Definition:: Configuration Name Definition.
|
|||
|
* Using Configuration Names:: Using Configuration Names.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Configuration Name Definition, Next: Using Configuration Names, Up: Configuration Names
|
|||
|
|
|||
|
4.1 Configuration Name Definition
|
|||
|
=================================
|
|||
|
|
|||
|
This is a string of the form CPU-MANUFACTURER-OPERATING_SYSTEM. In
|
|||
|
some cases, this is extended to a four part form:
|
|||
|
CPU-MANUFACTURER-KERNEL-OPERATING_SYSTEM.
|
|||
|
|
|||
|
When using a configuration name in a configure option, it is normally
|
|||
|
not necessary to specify an entire name. In particular, the
|
|||
|
MANUFACTURER field is often omitted, leading to strings such as
|
|||
|
`i386-linux' or `sparc-sunos'. The shell script `config.sub' will
|
|||
|
translate these shortened strings into the canonical form. autoconf
|
|||
|
will arrange for `config.sub' to be run automatically when it is needed.
|
|||
|
|
|||
|
The fields of a configuration name are as follows:
|
|||
|
|
|||
|
CPU
|
|||
|
The type of processor. This is typically something like `i386' or
|
|||
|
`sparc'. More specific variants are used as well, such as
|
|||
|
`mipsel' to indicate a little endian MIPS processor.
|
|||
|
|
|||
|
MANUFACTURER
|
|||
|
A somewhat freeform field which indicates the manufacturer of the
|
|||
|
system. This is often simply `unknown'. Other common strings are
|
|||
|
`pc' for an IBM PC compatible system, or the name of a workstation
|
|||
|
vendor, such as `sun'.
|
|||
|
|
|||
|
OPERATING_SYSTEM
|
|||
|
The name of the operating system which is run on the system. This
|
|||
|
will be something like `solaris2.5' or `irix6.3'. There is no
|
|||
|
particular restriction on the version number, and strings like
|
|||
|
`aix4.1.4.0' are seen. For an embedded system, which has no
|
|||
|
operating system, this field normally indicates the type of object
|
|||
|
file format, such as `elf' or `coff'.
|
|||
|
|
|||
|
KERNEL
|
|||
|
This is used mainly for GNU/Linux. A typical GNU/Linux
|
|||
|
configuration name is `i586-pc-linux-gnulibc1'. In this case the
|
|||
|
kernel, `linux', is separated from the operating system,
|
|||
|
`gnulibc1'.
|
|||
|
|
|||
|
The shell script `config.guess' will normally print the correct
|
|||
|
configuration name for the system on which it is run. It does by
|
|||
|
running `uname' and by examining other characteristics of the system.
|
|||
|
|
|||
|
Because `config.guess' can normally determine the configuration name
|
|||
|
for a machine, it is normally only necessary to specify a configuration
|
|||
|
name when building a cross-compiler or when building using a
|
|||
|
cross-compiler.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Using Configuration Names, Prev: Configuration Name Definition, Up: Configuration Names
|
|||
|
|
|||
|
4.2 Using Configuration Names
|
|||
|
=============================
|
|||
|
|
|||
|
A configure script will sometimes have to make a decision based on a
|
|||
|
configuration name. You will need to do this if you have to compile
|
|||
|
code differently based on something which can not be tested using a
|
|||
|
standard autoconf feature test.
|
|||
|
|
|||
|
It is normally better to test for particular features, rather than to
|
|||
|
test for a particular system. This is because as Unix evolves,
|
|||
|
different systems copy features from one another. Even if you need to
|
|||
|
determine whether the feature is supported based on a configuration
|
|||
|
name, you should define a macro which describes the feature, rather than
|
|||
|
defining a macro which describes the particular system you are on.
|
|||
|
|
|||
|
Testing for a particular system is normally done using a case
|
|||
|
statement in `configure.in'. The case statement might look something
|
|||
|
like the following, assuming that `host' is a shell variable holding a
|
|||
|
canonical configuration name (which will be the case if `configure.in'
|
|||
|
uses the `AC_CANONICAL_HOST' or `AC_CANONICAL_SYSTEM' macro).
|
|||
|
|
|||
|
case "${host}" in
|
|||
|
i[3-7]86-*-linux-gnu*) do something ;;
|
|||
|
sparc*-sun-solaris2.[56789]*) do something ;;
|
|||
|
sparc*-sun-solaris*) do something ;;
|
|||
|
mips*-*-elf*) do something ;;
|
|||
|
esac
|
|||
|
|
|||
|
It is particularly important to use `*' after the operating system
|
|||
|
field, in order to match the version number which will be generated by
|
|||
|
`config.guess'.
|
|||
|
|
|||
|
In most cases you must be careful to match a range of processor
|
|||
|
types. For most processor families, a trailing `*' suffices, as in
|
|||
|
`mips*' above. For the i386 family, something along the lines of
|
|||
|
`i[3-7]86' suffices at present. For the m68k family, you will need
|
|||
|
something like `m68*'. Of course, if you do not need to match on the
|
|||
|
processor, it is simpler to just replace the entire field by a `*', as
|
|||
|
in `*-*-irix*'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Cross Compilation Tools, Next: Canadian Cross, Prev: Configuration Names, Up: Top
|
|||
|
|
|||
|
5 Cross Compilation Tools
|
|||
|
*************************
|
|||
|
|
|||
|
The GNU configure and build system can be used to build "cross
|
|||
|
compilation" tools. A cross compilation tool is a tool which runs on
|
|||
|
one system and produces code which runs on another system.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Cross Compilation Concepts:: Cross Compilation Concepts.
|
|||
|
* Host and Target:: Host and Target.
|
|||
|
* Using the Host Type:: Using the Host Type.
|
|||
|
* Specifying the Target:: Specifying the Target.
|
|||
|
* Using the Target Type:: Using the Target Type.
|
|||
|
* Cross Tools in the Cygnus Tree:: Cross Tools in the Cygnus Tree
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Cross Compilation Concepts, Next: Host and Target, Up: Cross Compilation Tools
|
|||
|
|
|||
|
5.1 Cross Compilation Concepts
|
|||
|
==============================
|
|||
|
|
|||
|
A compiler which produces programs which run on a different system is a
|
|||
|
cross compilation compiler, or simply a "cross compiler". Similarly,
|
|||
|
we speak of cross assemblers, cross linkers, etc.
|
|||
|
|
|||
|
In the normal case, a compiler produces code which runs on the same
|
|||
|
system as the one on which the compiler runs. When it is necessary to
|
|||
|
distinguish this case from the cross compilation case, such a compiler
|
|||
|
is called a "native compiler". Similarly, we speak of native
|
|||
|
assemblers, etc.
|
|||
|
|
|||
|
Although the debugger is not strictly speaking a compilation tool,
|
|||
|
it is nevertheless meaningful to speak of a cross debugger: a debugger
|
|||
|
which is used to debug code which runs on another system. Everything
|
|||
|
that is said below about configuring cross compilation tools applies to
|
|||
|
the debugger as well.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Host and Target, Next: Using the Host Type, Prev: Cross Compilation Concepts, Up: Cross Compilation Tools
|
|||
|
|
|||
|
5.2 Host and Target
|
|||
|
===================
|
|||
|
|
|||
|
When building cross compilation tools, there are two different systems
|
|||
|
involved: the system on which the tools will run, and the system for
|
|||
|
which the tools generate code.
|
|||
|
|
|||
|
The system on which the tools will run is called the "host" system.
|
|||
|
|
|||
|
The system for which the tools generate code is called the "target"
|
|||
|
system.
|
|||
|
|
|||
|
For example, suppose you have a compiler which runs on a GNU/Linux
|
|||
|
system and generates ELF programs for a MIPS embedded system. In this
|
|||
|
case the GNU/Linux system is the host, and the MIPS ELF system is the
|
|||
|
target. Such a compiler could be called a GNU/Linux cross MIPS ELF
|
|||
|
compiler, or, equivalently, a `i386-linux-gnu' cross `mips-elf'
|
|||
|
compiler.
|
|||
|
|
|||
|
Naturally, most programs are not cross compilation tools. For those
|
|||
|
programs, it does not make sense to speak of a target. It only makes
|
|||
|
sense to speak of a target for tools like `gcc' or the `binutils' which
|
|||
|
actually produce running code. For example, it does not make sense to
|
|||
|
speak of the target of a tool like `bison' or `make'.
|
|||
|
|
|||
|
Most cross compilation tools can also serve as native tools. For a
|
|||
|
native compilation tool, it is still meaningful to speak of a target.
|
|||
|
For a native tool, the target is the same as the host. For example, for
|
|||
|
a GNU/Linux native compiler, the host is GNU/Linux, and the target is
|
|||
|
also GNU/Linux.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Using the Host Type, Next: Specifying the Target, Prev: Host and Target, Up: Cross Compilation Tools
|
|||
|
|
|||
|
5.3 Using the Host Type
|
|||
|
=======================
|
|||
|
|
|||
|
In almost all cases the host system is the system on which you run the
|
|||
|
`configure' script, and on which you build the tools (for the case when
|
|||
|
they differ, *note Canadian Cross::).
|
|||
|
|
|||
|
If your configure script needs to know the configuration name of the
|
|||
|
host system, and the package is not a cross compilation tool and
|
|||
|
therefore does not have a target, put `AC_CANONICAL_HOST' in
|
|||
|
`configure.in'. This macro will arrange to define a few shell
|
|||
|
variables when the `configure' script is run.
|
|||
|
|
|||
|
`host'
|
|||
|
The canonical configuration name of the host. This will normally
|
|||
|
be determined by running the `config.guess' shell script, although
|
|||
|
the user is permitted to override this by using an explicit
|
|||
|
`--host' option.
|
|||
|
|
|||
|
`host_alias'
|
|||
|
In the unusual case that the user used an explicit `--host' option,
|
|||
|
this will be the argument to `--host'. In the normal case, this
|
|||
|
will be the same as the `host' variable.
|
|||
|
|
|||
|
`host_cpu'
|
|||
|
`host_vendor'
|
|||
|
`host_os'
|
|||
|
The first three parts of the canonical configuration name.
|
|||
|
|
|||
|
The shell variables may be used by putting shell code in
|
|||
|
`configure.in'. For an example, see *Note Using Configuration Names::.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Specifying the Target, Next: Using the Target Type, Prev: Using the Host Type, Up: Cross Compilation Tools
|
|||
|
|
|||
|
5.4 Specifying the Target
|
|||
|
=========================
|
|||
|
|
|||
|
By default, the `configure' script will assume that the target is the
|
|||
|
same as the host. This is the more common case; for example, it leads
|
|||
|
to a native compiler rather than a cross compiler.
|
|||
|
|
|||
|
If you want to build a cross compilation tool, you must specify the
|
|||
|
target explicitly by using the `--target' option when you run
|
|||
|
`configure'. The argument to `--target' is the configuration name of
|
|||
|
the system for which you wish to generate code. *Note Configuration
|
|||
|
Names::.
|
|||
|
|
|||
|
For example, to build tools which generate code for a MIPS ELF
|
|||
|
embedded system, you would use `--target mips-elf'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Using the Target Type, Next: Cross Tools in the Cygnus Tree, Prev: Specifying the Target, Up: Cross Compilation Tools
|
|||
|
|
|||
|
5.5 Using the Target Type
|
|||
|
=========================
|
|||
|
|
|||
|
When writing `configure.in' for a cross compilation tool, you will need
|
|||
|
to use information about the target. To do this, put
|
|||
|
`AC_CANONICAL_SYSTEM' in `configure.in'.
|
|||
|
|
|||
|
`AC_CANONICAL_SYSTEM' will look for a `--target' option and
|
|||
|
canonicalize it using the `config.sub' shell script. It will also run
|
|||
|
`AC_CANONICAL_HOST' (*note Using the Host Type::).
|
|||
|
|
|||
|
The target type will be recorded in the following shell variables.
|
|||
|
Note that the host versions of these variables will also be defined by
|
|||
|
`AC_CANONICAL_HOST'.
|
|||
|
|
|||
|
`target'
|
|||
|
The canonical configuration name of the target.
|
|||
|
|
|||
|
`target_alias'
|
|||
|
The argument to the `--target' option. If the user did not specify
|
|||
|
a `--target' option, this will be the same as `host_alias'.
|
|||
|
|
|||
|
`target_cpu'
|
|||
|
`target_vendor'
|
|||
|
`target_os'
|
|||
|
The first three parts of the canonical target configuration name.
|
|||
|
|
|||
|
Note that if `host' and `target' are the same string, you can assume
|
|||
|
a native configuration. If they are different, you can assume a cross
|
|||
|
configuration.
|
|||
|
|
|||
|
It is arguably possible for `host' and `target' to represent the
|
|||
|
same system, but for the strings to not be identical. For example, if
|
|||
|
`config.guess' returns `sparc-sun-sunos4.1.4', and somebody configures
|
|||
|
with `--target sparc-sun-sunos4.1', then the slight differences between
|
|||
|
the two versions of SunOS may be unimportant for your tool. However,
|
|||
|
in the general case it can be quite difficult to determine whether the
|
|||
|
differences between two configuration names are significant or not.
|
|||
|
Therefore, by convention, if the user specifies a `--target' option
|
|||
|
without specifying a `--host' option, it is assumed that the user wants
|
|||
|
to configure a cross compilation tool.
|
|||
|
|
|||
|
The variables `target' and `target_alias' should be handled
|
|||
|
differently.
|
|||
|
|
|||
|
In general, whenever the user may actually see a string,
|
|||
|
`target_alias' should be used. This includes anything which may appear
|
|||
|
in the file system, such as a directory name or part of a tool name.
|
|||
|
It also includes any tool output, unless it is clearly labelled as the
|
|||
|
canonical target configuration name. This permits the user to use the
|
|||
|
`--target' option to specify how the tool will appear to the outside
|
|||
|
world.
|
|||
|
|
|||
|
On the other hand, when checking for characteristics of the target
|
|||
|
system, `target' should be used. This is because a wide variety of
|
|||
|
`--target' options may map into the same canonical configuration name.
|
|||
|
You should not attempt to duplicate the canonicalization done by
|
|||
|
`config.sub' in your own code.
|
|||
|
|
|||
|
By convention, cross tools are installed with a prefix of the
|
|||
|
argument used with the `--target' option, also known as `target_alias'
|
|||
|
(*note Using the Target Type::). If the user does not use the
|
|||
|
`--target' option, and thus is building a native tool, no prefix is
|
|||
|
used.
|
|||
|
|
|||
|
For example, if gcc is configured with `--target mips-elf', then the
|
|||
|
installed binary will be named `mips-elf-gcc'. If gcc is configured
|
|||
|
without a `--target' option, then the installed binary will be named
|
|||
|
`gcc'.
|
|||
|
|
|||
|
The autoconf macro `AC_ARG_PROGRAM' will handle this for you. If
|
|||
|
you are using automake, no more need be done; the programs will
|
|||
|
automatically be installed with the correct prefixes. Otherwise, see
|
|||
|
the autoconf documentation for `AC_ARG_PROGRAM'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Cross Tools in the Cygnus Tree, Prev: Using the Target Type, Up: Cross Compilation Tools
|
|||
|
|
|||
|
5.6 Cross Tools in the Cygnus Tree
|
|||
|
==================================
|
|||
|
|
|||
|
The Cygnus tree is used for various packages including gdb, the GNU
|
|||
|
binutils, and egcs. It is also, of course, used for Cygnus releases.
|
|||
|
|
|||
|
In the Cygnus tree, the top level `configure' script uses the old
|
|||
|
Cygnus configure system, not autoconf. The top level `Makefile.in' is
|
|||
|
written to build packages based on what is in the source tree, and
|
|||
|
supports building a large number of tools in a single
|
|||
|
`configure'/`make' step.
|
|||
|
|
|||
|
The Cygnus tree may be configured with a `--target' option. The
|
|||
|
`--target' option applies recursively to every subdirectory, and
|
|||
|
permits building an entire set of cross tools at once.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Host and Target Libraries:: Host and Target Libraries.
|
|||
|
* Target Library Configure Scripts:: Target Library Configure Scripts.
|
|||
|
* Make Targets in Cygnus Tree:: Make Targets in Cygnus Tree.
|
|||
|
* Target libiberty:: Target libiberty
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Host and Target Libraries, Next: Target Library Configure Scripts, Up: Cross Tools in the Cygnus Tree
|
|||
|
|
|||
|
5.6.1 Host and Target Libraries
|
|||
|
-------------------------------
|
|||
|
|
|||
|
The Cygnus tree distinguishes host libraries from target libraries.
|
|||
|
|
|||
|
Host libraries are built with the compiler used to build the programs
|
|||
|
which run on the host, which is called the host compiler. This includes
|
|||
|
libraries such as `bfd' and `tcl'. These libraries are built with the
|
|||
|
host compiler, and are linked into programs like the binutils or gcc
|
|||
|
which run on the host.
|
|||
|
|
|||
|
Target libraries are built with the target compiler. If gcc is
|
|||
|
present in the source tree, then the target compiler is the gcc that is
|
|||
|
built using the host compiler. Target libraries are libraries such as
|
|||
|
`newlib' and `libstdc++'. These libraries are not linked into the host
|
|||
|
programs, but are instead made available for use with programs built
|
|||
|
with the target compiler.
|
|||
|
|
|||
|
For the rest of this section, assume that gcc is present in the
|
|||
|
source tree, so that it will be used to build the target libraries.
|
|||
|
|
|||
|
There is a complication here. The configure process needs to know
|
|||
|
which compiler you are going to use to build a tool; otherwise, the
|
|||
|
feature tests will not work correctly. The Cygnus tree handles this by
|
|||
|
not configuring the target libraries until the target compiler is
|
|||
|
built. In order to permit everything to build using a single
|
|||
|
`configure'/`make', the configuration of the target libraries is
|
|||
|
actually triggered during the make step.
|
|||
|
|
|||
|
When the target libraries are configured, the `--target' option is
|
|||
|
not used. Instead, the `--host' option is used with the argument of
|
|||
|
the `--target' option for the overall configuration. If no `--target'
|
|||
|
option was used for the overall configuration, the `--host' option will
|
|||
|
be passed with the output of the `config.guess' shell script. Any
|
|||
|
`--build' option is passed down unchanged.
|
|||
|
|
|||
|
This translation of configuration options is done because since the
|
|||
|
target libraries are compiled with the target compiler, they are being
|
|||
|
built in order to run on the target of the overall configuration. By
|
|||
|
the definition of host, this means that their host system is the same as
|
|||
|
the target system of the overall configuration.
|
|||
|
|
|||
|
The same process is used for both a native configuration and a cross
|
|||
|
configuration. Even when using a native configuration, the target
|
|||
|
libraries will be configured and built using the newly built compiler.
|
|||
|
This is particularly important for the C++ libraries, since there is no
|
|||
|
reason to assume that the C++ compiler used to build the host tools (if
|
|||
|
there even is one) uses the same ABI as the g++ compiler which will be
|
|||
|
used to build the target libraries.
|
|||
|
|
|||
|
There is one difference between a native configuration and a cross
|
|||
|
configuration. In a native configuration, the target libraries are
|
|||
|
normally configured and built as siblings of the host tools. In a cross
|
|||
|
configuration, the target libraries are normally built in a subdirectory
|
|||
|
whose name is the argument to `--target'. This is mainly for
|
|||
|
historical reasons.
|
|||
|
|
|||
|
To summarize, running `configure' in the Cygnus tree configures all
|
|||
|
the host libraries and tools, but does not configure any of the target
|
|||
|
libraries. Running `make' then does the following steps:
|
|||
|
|
|||
|
* Build the host libraries.
|
|||
|
|
|||
|
* Build the host programs, including gcc. Note that we call gcc
|
|||
|
both a host program (since it runs on the host) and a target
|
|||
|
compiler (since it generates code for the target).
|
|||
|
|
|||
|
* Using the newly built target compiler, configure the target
|
|||
|
libraries.
|
|||
|
|
|||
|
* Build the target libraries.
|
|||
|
|
|||
|
The steps need not be done in precisely this order, since they are
|
|||
|
actually controlled by `Makefile' targets.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Target Library Configure Scripts, Next: Make Targets in Cygnus Tree, Prev: Host and Target Libraries, Up: Cross Tools in the Cygnus Tree
|
|||
|
|
|||
|
5.6.2 Target Library Configure Scripts
|
|||
|
--------------------------------------
|
|||
|
|
|||
|
There are a few things you must know in order to write a configure
|
|||
|
script for a target library. This is just a quick sketch, and beginners
|
|||
|
shouldn't worry if they don't follow everything here.
|
|||
|
|
|||
|
The target libraries are configured and built using a newly built
|
|||
|
target compiler. There may not be any startup files or libraries for
|
|||
|
this target compiler. In fact, those files will probably be built as
|
|||
|
part of some target library, which naturally means that they will not
|
|||
|
exist when your target library is configured.
|
|||
|
|
|||
|
This means that the configure script for a target library may not use
|
|||
|
any test which requires doing a link. This unfortunately includes many
|
|||
|
useful autoconf macros, such as `AC_CHECK_FUNCS'. autoconf macros
|
|||
|
which do a compile but not a link, such as `AC_CHECK_HEADERS', may be
|
|||
|
used.
|
|||
|
|
|||
|
This is a severe restriction, but normally not a fatal one, as target
|
|||
|
libraries can often assume the presence of other target libraries, and
|
|||
|
thus know which functions will be available.
|
|||
|
|
|||
|
As of this writing, the autoconf macro `AC_PROG_CC' does a link to
|
|||
|
make sure that the compiler works. This may fail in a target library,
|
|||
|
so target libraries must use a different set of macros to locate the
|
|||
|
compiler. See the `configure.in' file in a directory like `libiberty'
|
|||
|
or `libgloss' for an example.
|
|||
|
|
|||
|
As noted in the previous section, target libraries are sometimes
|
|||
|
built in directories which are siblings to the host tools, and are
|
|||
|
sometimes built in a subdirectory. The `--with-target-subdir' configure
|
|||
|
option will be passed when the library is configured. Its value will be
|
|||
|
an empty string if the target library is a sibling. Its value will be
|
|||
|
the name of the subdirectory if the target library is in a subdirectory.
|
|||
|
|
|||
|
If the overall build is not a native build (i.e., the overall
|
|||
|
configure used the `--target' option), then the library will be
|
|||
|
configured with the `--with-cross-host' option. The value of this
|
|||
|
option will be the host system of the overall build. Recall that the
|
|||
|
host system of the library will be the target of the overall build. If
|
|||
|
the overall build is a native build, the `--with-cross-host' option
|
|||
|
will not be used.
|
|||
|
|
|||
|
A library which can be built both standalone and as a target library
|
|||
|
may want to install itself into different directories depending upon the
|
|||
|
case. When built standalone, or when built native, the library should
|
|||
|
be installed in `$(libdir)'. When built as a target library which is
|
|||
|
not native, the library should be installed in `$(tooldir)/lib'. The
|
|||
|
`--with-cross-host' option may be used to distinguish these cases.
|
|||
|
|
|||
|
This same test of `--with-cross-host' may be used to see whether it
|
|||
|
is OK to use link tests in the configure script. If the
|
|||
|
`--with-cross-host' option is not used, then the library is being built
|
|||
|
either standalone or native, and a link should work.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Make Targets in Cygnus Tree, Next: Target libiberty, Prev: Target Library Configure Scripts, Up: Cross Tools in the Cygnus Tree
|
|||
|
|
|||
|
5.6.3 Make Targets in Cygnus Tree
|
|||
|
---------------------------------
|
|||
|
|
|||
|
The top level `Makefile' in the Cygnus tree defines targets for every
|
|||
|
known subdirectory.
|
|||
|
|
|||
|
For every subdirectory DIR which holds a host library or program,
|
|||
|
the `Makefile' target `all-DIR' will build that library or program.
|
|||
|
|
|||
|
There are dependencies among host tools. For example, building gcc
|
|||
|
requires first building gas, because the gcc build process invokes the
|
|||
|
target assembler. These dependencies are reflected in the top level
|
|||
|
`Makefile'.
|
|||
|
|
|||
|
For every subdirectory DIR which holds a target library, the
|
|||
|
`Makefile' target `configure-target-DIR' will configure that library.
|
|||
|
The `Makefile' target `all-target-DIR' will build that library.
|
|||
|
|
|||
|
Every `configure-target-DIR' target depends upon `all-gcc', since
|
|||
|
gcc, the target compiler, is required to configure the tool. Every
|
|||
|
`all-target-DIR' target depends upon the corresponding
|
|||
|
`configure-target-DIR' target.
|
|||
|
|
|||
|
There are several other targets which may be of interest for each
|
|||
|
directory: `install-DIR', `clean-DIR', and `check-DIR'. There are also
|
|||
|
corresponding `target' versions of these for the target libraries ,
|
|||
|
such as `install-target-DIR'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Target libiberty, Prev: Make Targets in Cygnus Tree, Up: Cross Tools in the Cygnus Tree
|
|||
|
|
|||
|
5.6.4 Target libiberty
|
|||
|
----------------------
|
|||
|
|
|||
|
The `libiberty' subdirectory is currently a special case, in that it is
|
|||
|
the only directory which is built both using the host compiler and
|
|||
|
using the target compiler.
|
|||
|
|
|||
|
This is because the files in `libiberty' are used when building the
|
|||
|
host tools, and they are also incorporated into the `libstdc++' target
|
|||
|
library as support code.
|
|||
|
|
|||
|
This duality does not pose any particular difficulties. It means
|
|||
|
that there are targets for both `all-libiberty' and
|
|||
|
`all-target-libiberty'.
|
|||
|
|
|||
|
In a native configuration, when target libraries are not built in a
|
|||
|
subdirectory, the same objects are normally used as both the host build
|
|||
|
and the target build. This is normally OK, since libiberty contains
|
|||
|
only C code, and in a native configuration the results of the host
|
|||
|
compiler and the target compiler are normally interoperable.
|
|||
|
|
|||
|
Irix 6 is again an exception here, since the SGI native compiler
|
|||
|
defaults to using the `O32' ABI, and gcc defaults to using the `N32'
|
|||
|
ABI. On Irix 6, the target libraries are built in a subdirectory even
|
|||
|
for a native configuration, avoiding this problem.
|
|||
|
|
|||
|
There are currently no other libraries built for both the host and
|
|||
|
the target, but there is no conceptual problem with adding more.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Canadian Cross, Next: Cygnus Configure, Prev: Cross Compilation Tools, Up: Top
|
|||
|
|
|||
|
6 Canadian Cross
|
|||
|
****************
|
|||
|
|
|||
|
It is possible to use the GNU configure and build system to build a
|
|||
|
program which will run on a system which is different from the system on
|
|||
|
which the tools are built. In other words, it is possible to build
|
|||
|
programs using a cross compiler.
|
|||
|
|
|||
|
This is referred to as a "Canadian Cross".
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Canadian Cross Example:: Canadian Cross Example.
|
|||
|
* Canadian Cross Concepts:: Canadian Cross Concepts.
|
|||
|
* Build Cross Host Tools:: Build Cross Host Tools.
|
|||
|
* Build and Host Options:: Build and Host Options.
|
|||
|
* CCross not in Cygnus Tree:: Canadian Cross not in Cygnus Tree.
|
|||
|
* CCross in Cygnus Tree:: Canadian Cross in Cygnus Tree.
|
|||
|
* Supporting Canadian Cross:: Supporting Canadian Cross.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Canadian Cross Example, Next: Canadian Cross Concepts, Up: Canadian Cross
|
|||
|
|
|||
|
6.1 Canadian Cross Example
|
|||
|
==========================
|
|||
|
|
|||
|
Here is an example of a Canadian Cross.
|
|||
|
|
|||
|
While running on a GNU/Linux, you can build a program which will run
|
|||
|
on a Solaris system. You would use a GNU/Linux cross Solaris compiler
|
|||
|
to build the program.
|
|||
|
|
|||
|
Of course, you could not run the resulting program on your GNU/Linux
|
|||
|
system. You would have to copy it over to a Solaris system before you
|
|||
|
would run it.
|
|||
|
|
|||
|
Of course, you could also simply build the programs on the Solaris
|
|||
|
system in the first place. However, perhaps the Solaris system is not
|
|||
|
available for some reason; perhaps you actually don't have one, but you
|
|||
|
want to build the tools for somebody else to use. Or perhaps your
|
|||
|
GNU/Linux system is much faster than your Solaris system.
|
|||
|
|
|||
|
A Canadian Cross build is most frequently used when building
|
|||
|
programs to run on a non-Unix system, such as DOS or Windows. It may
|
|||
|
be simpler to configure and build on a Unix system than to support the
|
|||
|
configuration machinery on a non-Unix system.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Canadian Cross Concepts, Next: Build Cross Host Tools, Prev: Canadian Cross Example, Up: Canadian Cross
|
|||
|
|
|||
|
6.2 Canadian Cross Concepts
|
|||
|
===========================
|
|||
|
|
|||
|
When building a Canadian Cross, there are at least two different systems
|
|||
|
involved: the system on which the tools are being built, and the system
|
|||
|
on which the tools will run.
|
|||
|
|
|||
|
The system on which the tools are being built is called the "build"
|
|||
|
system.
|
|||
|
|
|||
|
The system on which the tools will run is called the host system.
|
|||
|
|
|||
|
For example, if you are building a Solaris program on a GNU/Linux
|
|||
|
system, as in the previous section, the build system would be GNU/Linux,
|
|||
|
and the host system would be Solaris.
|
|||
|
|
|||
|
It is, of course, possible to build a cross compiler using a Canadian
|
|||
|
Cross (i.e., build a cross compiler using a cross compiler). In this
|
|||
|
case, the system for which the resulting cross compiler generates code
|
|||
|
is called the target system. (For a more complete discussion of host
|
|||
|
and target systems, *note Host and Target::).
|
|||
|
|
|||
|
An example of building a cross compiler using a Canadian Cross would
|
|||
|
be building a Windows cross MIPS ELF compiler on a GNU/Linux system. In
|
|||
|
this case the build system would be GNU/Linux, the host system would be
|
|||
|
Windows, and the target system would be MIPS ELF.
|
|||
|
|
|||
|
The name Canadian Cross comes from the case when the build, host, and
|
|||
|
target systems are all different. At the time that these issues were
|
|||
|
all being hashed out, Canada had three national political parties.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Build Cross Host Tools, Next: Build and Host Options, Prev: Canadian Cross Concepts, Up: Canadian Cross
|
|||
|
|
|||
|
6.3 Build Cross Host Tools
|
|||
|
==========================
|
|||
|
|
|||
|
In order to configure a program for a Canadian Cross build, you must
|
|||
|
first build and install the set of cross tools you will use to build the
|
|||
|
program.
|
|||
|
|
|||
|
These tools will be build cross host tools. That is, they will run
|
|||
|
on the build system, and will produce code that runs on the host system.
|
|||
|
|
|||
|
It is easy to confuse the meaning of build and host here. Always
|
|||
|
remember that the build system is where you are doing the build, and the
|
|||
|
host system is where the resulting program will run. Therefore, you
|
|||
|
need a build cross host compiler.
|
|||
|
|
|||
|
In general, you must have a complete cross environment in order to do
|
|||
|
the build. This normally means a cross compiler, cross assembler, and
|
|||
|
so forth, as well as libraries and include files for the host system.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Build and Host Options, Next: CCross not in Cygnus Tree, Prev: Build Cross Host Tools, Up: Canadian Cross
|
|||
|
|
|||
|
6.4 Build and Host Options
|
|||
|
==========================
|
|||
|
|
|||
|
When you run `configure', you must use both the `--build' and `--host'
|
|||
|
options.
|
|||
|
|
|||
|
The `--build' option is used to specify the configuration name of
|
|||
|
the build system. This can normally be the result of running the
|
|||
|
`config.guess' shell script, and it is reasonable to use
|
|||
|
`--build=`config.guess`'.
|
|||
|
|
|||
|
The `--host' option is used to specify the configuration name of the
|
|||
|
host system.
|
|||
|
|
|||
|
As we explained earlier, `config.guess' is used to set the default
|
|||
|
value for the `--host' option (*note Using the Host Type::). We can
|
|||
|
now see that since `config.guess' returns the type of system on which
|
|||
|
it is run, it really identifies the build system. Since the host
|
|||
|
system is normally the same as the build system (i.e., people do not
|
|||
|
normally build using a cross compiler), it is reasonable to use the
|
|||
|
result of `config.guess' as the default for the host system when the
|
|||
|
`--host' option is not used.
|
|||
|
|
|||
|
It might seem that if the `--host' option were used without the
|
|||
|
`--build' option that the configure script could run `config.guess' to
|
|||
|
determine the build system, and presume a Canadian Cross if the result
|
|||
|
of `config.guess' differed from the `--host' option. However, for
|
|||
|
historical reasons, some configure scripts are routinely run using an
|
|||
|
explicit `--host' option, rather than using the default from
|
|||
|
`config.guess'. As noted earlier, it is difficult or impossible to
|
|||
|
reliably compare configuration names (*note Using the Target Type::).
|
|||
|
Therefore, by convention, if the `--host' option is used, but the
|
|||
|
`--build' option is not used, then the build system defaults to the
|
|||
|
host system.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: CCross not in Cygnus Tree, Next: CCross in Cygnus Tree, Prev: Build and Host Options, Up: Canadian Cross
|
|||
|
|
|||
|
6.5 Canadian Cross not in Cygnus Tree.
|
|||
|
======================================
|
|||
|
|
|||
|
If you are not using the Cygnus tree, you must explicitly specify the
|
|||
|
cross tools which you want to use to build the program. This is done by
|
|||
|
setting environment variables before running the `configure' script.
|
|||
|
|
|||
|
You must normally set at least the environment variables `CC', `AR',
|
|||
|
and `RANLIB' to the cross tools which you want to use to build.
|
|||
|
|
|||
|
For some programs, you must set additional cross tools as well, such
|
|||
|
as `AS', `LD', or `NM'.
|
|||
|
|
|||
|
You would set these environment variables to the build cross tools
|
|||
|
which you are going to use.
|
|||
|
|
|||
|
For example, if you are building a Solaris program on a GNU/Linux
|
|||
|
system, and your GNU/Linux cross Solaris compiler were named
|
|||
|
`solaris-gcc', then you would set the environment variable `CC' to
|
|||
|
`solaris-gcc'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: CCross in Cygnus Tree, Next: Supporting Canadian Cross, Prev: CCross not in Cygnus Tree, Up: Canadian Cross
|
|||
|
|
|||
|
6.6 Canadian Cross in Cygnus Tree
|
|||
|
=================================
|
|||
|
|
|||
|
This section describes configuring and building a Canadian Cross when
|
|||
|
using the Cygnus tree.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Standard Cygnus CCross:: Building a Normal Program.
|
|||
|
* Cross Cygnus CCross:: Building a Cross Program.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Standard Cygnus CCross, Next: Cross Cygnus CCross, Up: CCross in Cygnus Tree
|
|||
|
|
|||
|
6.6.1 Building a Normal Program
|
|||
|
-------------------------------
|
|||
|
|
|||
|
When configuring a Canadian Cross in the Cygnus tree, all the
|
|||
|
appropriate environment variables are automatically set to `HOST-TOOL',
|
|||
|
where HOST is the value used for the `--host' option, and TOOL is the
|
|||
|
name of the tool (e.g., `gcc', `as', etc.). These tools must be on
|
|||
|
your `PATH'.
|
|||
|
|
|||
|
Adding a prefix of HOST will give the usual name for the build cross
|
|||
|
host tools. To see this, consider that when these cross tools were
|
|||
|
built, they were configured to run on the build system and to produce
|
|||
|
code for the host system. That is, they were configured with a
|
|||
|
`--target' option that is the same as the system which we are now
|
|||
|
calling the host. Recall that the default name for installed cross
|
|||
|
tools uses the target system as a prefix (*note Using the Target
|
|||
|
Type::). Since that is the system which we are now calling the host,
|
|||
|
HOST is the right prefix to use.
|
|||
|
|
|||
|
For example, if you configure with `--build=i386-linux-gnu' and
|
|||
|
`--host=solaris', then the Cygnus tree will automatically default to
|
|||
|
using the compiler `solaris-gcc'. You must have previously built and
|
|||
|
installed this compiler, probably by doing a build with no `--host'
|
|||
|
option and with a `--target' option of `solaris'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Cross Cygnus CCross, Prev: Standard Cygnus CCross, Up: CCross in Cygnus Tree
|
|||
|
|
|||
|
6.6.2 Building a Cross Program
|
|||
|
------------------------------
|
|||
|
|
|||
|
There are additional considerations if you want to build a cross
|
|||
|
compiler, rather than a native compiler, in the Cygnus tree using a
|
|||
|
Canadian Cross.
|
|||
|
|
|||
|
When you build a cross compiler using the Cygnus tree, then the
|
|||
|
target libraries will normally be built with the newly built target
|
|||
|
compiler (*note Host and Target Libraries::). However, this will not
|
|||
|
work when building with a Canadian Cross. This is because the newly
|
|||
|
built target compiler will be a program which runs on the host system,
|
|||
|
and therefore will not be able to run on the build system.
|
|||
|
|
|||
|
Therefore, when building a cross compiler with the Cygnus tree, you
|
|||
|
must first install a set of build cross target tools. These tools will
|
|||
|
be used when building the target libraries.
|
|||
|
|
|||
|
Note that this is not a requirement of a Canadian Cross in general.
|
|||
|
For example, it would be possible to build just the host cross target
|
|||
|
tools on the build system, to copy the tools to the host system, and to
|
|||
|
build the target libraries on the host system. The requirement for
|
|||
|
build cross target tools is imposed by the Cygnus tree, which expects
|
|||
|
to be able to build both host programs and target libraries in a single
|
|||
|
`configure'/`make' step. Because it builds these in a single step, it
|
|||
|
expects to be able to build the target libraries on the build system,
|
|||
|
which means that it must use a build cross target toolchain.
|
|||
|
|
|||
|
For example, suppose you want to build a Windows cross MIPS ELF
|
|||
|
compiler on a GNU/Linux system. You must have previously installed
|
|||
|
both a GNU/Linux cross Windows compiler and a GNU/Linux cross MIPS ELF
|
|||
|
compiler.
|
|||
|
|
|||
|
In order to build the Windows (configuration name `i386-cygwin32')
|
|||
|
cross MIPS ELF (configure name `mips-elf') compiler, you might execute
|
|||
|
the following commands (long command lines are broken across lines with
|
|||
|
a trailing backslash as a continuation character).
|
|||
|
|
|||
|
mkdir linux-x-cygwin32
|
|||
|
cd linux-x-cygwin32
|
|||
|
SRCDIR/configure --target i386-cygwin32 --prefix=INSTALLDIR \
|
|||
|
--exec-prefix=INSTALLDIR/H-i386-linux
|
|||
|
make
|
|||
|
make install
|
|||
|
cd ..
|
|||
|
mkdir linux-x-mips-elf
|
|||
|
cd linux-x-mips-elf
|
|||
|
SRCDIR/configure --target mips-elf --prefix=INSTALLDIR \
|
|||
|
--exec-prefix=INSTALLDIR/H-i386-linux
|
|||
|
make
|
|||
|
make install
|
|||
|
cd ..
|
|||
|
mkdir cygwin32-x-mips-elf
|
|||
|
cd cygwin32-x-mips-elf
|
|||
|
SRCDIR/configure --build=i386-linux-gnu --host=i386-cygwin32 \
|
|||
|
--target=mips-elf --prefix=WININSTALLDIR \
|
|||
|
--exec-prefix=WININSTALLDIR/H-i386-cygwin32
|
|||
|
make
|
|||
|
make install
|
|||
|
|
|||
|
You would then copy the contents of WININSTALLDIR over to the
|
|||
|
Windows machine, and run the resulting programs.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Supporting Canadian Cross, Prev: CCross in Cygnus Tree, Up: Canadian Cross
|
|||
|
|
|||
|
6.7 Supporting Canadian Cross
|
|||
|
=============================
|
|||
|
|
|||
|
If you want to make it possible to build a program you are developing
|
|||
|
using a Canadian Cross, you must take some care when writing your
|
|||
|
configure and make rules. Simple cases will normally work correctly.
|
|||
|
However, it is not hard to write configure and make tests which will
|
|||
|
fail in a Canadian Cross.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* CCross in Configure:: Supporting Canadian Cross in Configure Scripts.
|
|||
|
* CCross in Make:: Supporting Canadian Cross in Makefiles.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: CCross in Configure, Next: CCross in Make, Up: Supporting Canadian Cross
|
|||
|
|
|||
|
6.7.1 Supporting Canadian Cross in Configure Scripts
|
|||
|
----------------------------------------------------
|
|||
|
|
|||
|
In a `configure.in' file, after calling `AC_PROG_CC', you can find out
|
|||
|
whether this is a Canadian Cross configure by examining the shell
|
|||
|
variable `cross_compiling'. In a Canadian Cross, which means that the
|
|||
|
compiler is a cross compiler, `cross_compiling' will be `yes'. In a
|
|||
|
normal configuration, `cross_compiling' will be `no'.
|
|||
|
|
|||
|
You ordinarily do not need to know the type of the build system in a
|
|||
|
configure script. However, if you do need that information, you can get
|
|||
|
it by using the macro `AC_CANONICAL_SYSTEM', the same macro that is
|
|||
|
used to determine the target system. This macro will set the variables
|
|||
|
`build', `build_alias', `build_cpu', `build_vendor', and `build_os',
|
|||
|
which correspond to the similar `target' and `host' variables, except
|
|||
|
that they describe the build system.
|
|||
|
|
|||
|
When writing tests in `configure.in', you must remember that you
|
|||
|
want to test the host environment, not the build environment.
|
|||
|
|
|||
|
Macros like `AC_CHECK_FUNCS' which use the compiler will test the
|
|||
|
host environment. That is because the tests will be done by running the
|
|||
|
compiler, which is actually a build cross host compiler. If the
|
|||
|
compiler can find the function, that means that the function is present
|
|||
|
in the host environment.
|
|||
|
|
|||
|
Tests like `test -f /dev/ptyp0', on the other hand, will test the
|
|||
|
build environment. Remember that the configure script is running on the
|
|||
|
build system, not the host system. If your configure scripts examines
|
|||
|
files, those files will be on the build system. Whatever you determine
|
|||
|
based on those files may or may not be the case on the host system.
|
|||
|
|
|||
|
Most autoconf macros will work correctly for a Canadian Cross. The
|
|||
|
main exception is `AC_TRY_RUN'. This macro tries to compile and run a
|
|||
|
test program. This will fail in a Canadian Cross, because the program
|
|||
|
will be compiled for the host system, which means that it will not run
|
|||
|
on the build system.
|
|||
|
|
|||
|
The `AC_TRY_RUN' macro provides an optional argument to tell the
|
|||
|
configure script what to do in a Canadian Cross. If that argument is
|
|||
|
not present, you will get a warning when you run `autoconf':
|
|||
|
warning: AC_TRY_RUN called without default to allow cross compiling
|
|||
|
This tells you that the resulting `configure' script will not work
|
|||
|
with a Canadian Cross.
|
|||
|
|
|||
|
In some cases while it may better to perform a test at configure
|
|||
|
time, it is also possible to perform the test at run time. In such a
|
|||
|
case you can use the cross compiling argument to `AC_TRY_RUN' to tell
|
|||
|
your program that the test could not be performed at configure time.
|
|||
|
|
|||
|
There are a few other autoconf macros which will not work correctly
|
|||
|
with a Canadian Cross: a partial list is `AC_FUNC_GETPGRP',
|
|||
|
`AC_FUNC_SETPGRP', `AC_FUNC_SETVBUF_REVERSED', and
|
|||
|
`AC_SYS_RESTARTABLE_SYSCALLS'. The `AC_CHECK_SIZEOF' macro is
|
|||
|
generally not very useful with a Canadian Cross; it permits an optional
|
|||
|
argument indicating the default size, but there is no way to know what
|
|||
|
the correct default should be.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: CCross in Make, Prev: CCross in Configure, Up: Supporting Canadian Cross
|
|||
|
|
|||
|
6.7.2 Supporting Canadian Cross in Makefiles.
|
|||
|
---------------------------------------------
|
|||
|
|
|||
|
The main Canadian Cross issue in a `Makefile' arises when you want to
|
|||
|
use a subsidiary program to generate code or data which you will then
|
|||
|
include in your real program.
|
|||
|
|
|||
|
If you compile this subsidiary program using `$(CC)' in the usual
|
|||
|
way, you will not be able to run it. This is because `$(CC)' will
|
|||
|
build a program for the host system, but the program is being built on
|
|||
|
the build system.
|
|||
|
|
|||
|
You must instead use a compiler for the build system, rather than the
|
|||
|
host system. In the Cygnus tree, this make variable `$(CC_FOR_BUILD)'
|
|||
|
will hold a compiler for the build system.
|
|||
|
|
|||
|
Note that you should not include `config.h' in a file you are
|
|||
|
compiling with `$(CC_FOR_BUILD)'. The `configure' script will build
|
|||
|
`config.h' with information for the host system. However, you are
|
|||
|
compiling the file using a compiler for the build system (a native
|
|||
|
compiler). Subsidiary programs are normally simple filters which do no
|
|||
|
user interaction, and it is normally possible to write them in a highly
|
|||
|
portable fashion so that the absence of `config.h' is not crucial.
|
|||
|
|
|||
|
The gcc `Makefile.in' shows a complex situation in which certain
|
|||
|
files, such as `rtl.c', must be compiled into both subsidiary programs
|
|||
|
run on the build system and into the final program. This approach may
|
|||
|
be of interest for advanced build system hackers. Note that the build
|
|||
|
system compiler is rather confusingly called `HOST_CC'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Cygnus Configure, Next: Multilibs, Prev: Canadian Cross, Up: Top
|
|||
|
|
|||
|
7 Cygnus Configure
|
|||
|
******************
|
|||
|
|
|||
|
The Cygnus configure script predates autoconf. All of its interesting
|
|||
|
features have been incorporated into autoconf. No new programs should
|
|||
|
be written to use the Cygnus configure script.
|
|||
|
|
|||
|
However, the Cygnus configure script is still used in a few places:
|
|||
|
at the top of the Cygnus tree and in a few target libraries in the
|
|||
|
Cygnus tree. Until those uses have been replaced with autoconf, some
|
|||
|
brief notes are appropriate here. This is not complete documentation,
|
|||
|
but it should be possible to use this as a guide while examining the
|
|||
|
scripts themselves.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Cygnus Configure Basics:: Cygnus Configure Basics.
|
|||
|
* Cygnus Configure in C++ Libraries:: Cygnus Configure in C++ Libraries.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Cygnus Configure Basics, Next: Cygnus Configure in C++ Libraries, Up: Cygnus Configure
|
|||
|
|
|||
|
7.1 Cygnus Configure Basics
|
|||
|
===========================
|
|||
|
|
|||
|
Cygnus configure does not use any generated files; there is no program
|
|||
|
corresponding to `autoconf'. Instead, there is a single shell script
|
|||
|
named `configure' which may be found at the top of the Cygnus tree.
|
|||
|
This shell script was written by hand; it was not generated by
|
|||
|
autoconf, and it is incorrect, and indeed harmful, to run `autoconf' in
|
|||
|
the top level of a Cygnus tree.
|
|||
|
|
|||
|
Cygnus configure works in a particular directory by examining the
|
|||
|
file `configure.in' in that directory. That file is broken into four
|
|||
|
separate shell scripts.
|
|||
|
|
|||
|
The first is the contents of `configure.in' up to a line that starts
|
|||
|
with `# per-host:'. This is the common part.
|
|||
|
|
|||
|
The second is the rest of `configure.in' up to a line that starts
|
|||
|
with `# per-target:'. This is the per host part.
|
|||
|
|
|||
|
The third is the rest of `configure.in' up to a line that starts
|
|||
|
with `# post-target:'. This is the per target part.
|
|||
|
|
|||
|
The fourth is the remainder of `configure.in'. This is the post
|
|||
|
target part.
|
|||
|
|
|||
|
If any of these comment lines are missing, the corresponding shell
|
|||
|
script is empty.
|
|||
|
|
|||
|
Cygnus configure will first execute the common part. This must set
|
|||
|
the shell variable `srctrigger' to the name of a source file, to
|
|||
|
confirm that Cygnus configure is looking at the right directory. This
|
|||
|
may set the shell variables `package_makefile_frag' and
|
|||
|
`package_makefile_rules_frag'.
|
|||
|
|
|||
|
Cygnus configure will next set the `build' and `host' shell
|
|||
|
variables, and execute the per host part. This may set the shell
|
|||
|
variable `host_makefile_frag'.
|
|||
|
|
|||
|
Cygnus configure will next set the `target' variable, and execute
|
|||
|
the per target part. This may set the shell variable
|
|||
|
`target_makefile_frag'.
|
|||
|
|
|||
|
Any of these scripts may set the `subdirs' shell variable. This
|
|||
|
variable is a list of subdirectories where a `Makefile.in' file may be
|
|||
|
found. Cygnus configure will automatically look for a `Makefile.in'
|
|||
|
file in the current directory. The `subdirs' shell variable is not
|
|||
|
normally used, and I believe that the only directory which uses it at
|
|||
|
present is `newlib'.
|
|||
|
|
|||
|
For each `Makefile.in', Cygnus configure will automatically create a
|
|||
|
`Makefile' by adding definitions for `make' variables such as `host'
|
|||
|
and `target', and automatically editing the values of `make' variables
|
|||
|
such as `prefix' if they are present.
|
|||
|
|
|||
|
Also, if any of the `makefile_frag' shell variables are set, Cygnus
|
|||
|
configure will interpret them as file names relative to either the
|
|||
|
working directory or the source directory, and will read the contents of
|
|||
|
the file into the generated `Makefile'. The file contents will be read
|
|||
|
in after the first line in `Makefile.in' which starts with `####'.
|
|||
|
|
|||
|
These `Makefile' fragments are used to customize behaviour for a
|
|||
|
particular host or target. They serve to select particular files to
|
|||
|
compile, and to define particular preprocessor macros by providing
|
|||
|
values for `make' variables which are then used during compilation.
|
|||
|
Cygnus configure, unlike autoconf, normally does not do feature tests,
|
|||
|
and normally requires support to be added manually for each new host.
|
|||
|
|
|||
|
The `Makefile' fragment support is similar to the autoconf
|
|||
|
`AC_SUBST_FILE' macro.
|
|||
|
|
|||
|
After creating each `Makefile', the post target script will be run
|
|||
|
(i.e., it may be run several times). This script may further customize
|
|||
|
the `Makefile'. When it is run, the shell variable `Makefile' will
|
|||
|
hold the name of the `Makefile', including the appropriate directory
|
|||
|
component.
|
|||
|
|
|||
|
Like an autoconf generated `configure' script, Cygnus configure will
|
|||
|
create a file named `config.status' which, when run, will automatically
|
|||
|
recreate the configuration. The `config.status' file will simply
|
|||
|
execute the Cygnus configure script again with the appropriate
|
|||
|
arguments.
|
|||
|
|
|||
|
Any of the parts of `configure.in' may set the shell variables
|
|||
|
`files' and `links'. Cygnus configure will set up symlinks from the
|
|||
|
names in `links' to the files named in `files'. This is similar to the
|
|||
|
autoconf `AC_LINK_FILES' macro.
|
|||
|
|
|||
|
Finally, any of the parts of `configure.in' may set the shell
|
|||
|
variable `configdirs' to a set of subdirectories. If it is set, Cygnus
|
|||
|
configure will recursively run the configure process in each
|
|||
|
subdirectory. If the subdirectory uses Cygnus configure, it will
|
|||
|
contain a `configure.in' file but no `configure' file, in which case
|
|||
|
Cygnus configure will invoke itself recursively. If the subdirectory
|
|||
|
has a `configure' file, Cygnus configure assumes that it is an autoconf
|
|||
|
generated `configure' script, and simply invokes it directly.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Cygnus Configure in C++ Libraries, Prev: Cygnus Configure Basics, Up: Cygnus Configure
|
|||
|
|
|||
|
7.2 Cygnus Configure in C++ Libraries
|
|||
|
=====================================
|
|||
|
|
|||
|
The C++ library configure system, written by Per Bothner, deserves
|
|||
|
special mention. It uses Cygnus configure, but it does feature testing
|
|||
|
like that done by autoconf generated `configure' scripts. This
|
|||
|
approach is used in the libraries `libio', `libstdc++', and `libg++'.
|
|||
|
|
|||
|
Most of the `Makefile' information is written out by the shell
|
|||
|
script `libio/config.shared'. Each `configure.in' file sets certain
|
|||
|
shell variables, and then invokes `config.shared' to create two package
|
|||
|
`Makefile' fragments. These fragments are then incorporated into the
|
|||
|
resulting `Makefile' by the Cygnus configure script.
|
|||
|
|
|||
|
The file `_G_config.h' is created in the `libio' object directory by
|
|||
|
running the shell script `libio/gen-params'. This shell script uses
|
|||
|
feature tests to define macros and typedefs in `_G_config.h'.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Multilibs, Next: FAQ, Prev: Cygnus Configure, Up: Top
|
|||
|
|
|||
|
8 Multilibs
|
|||
|
***********
|
|||
|
|
|||
|
For some targets gcc may have different processor requirements depending
|
|||
|
upon command line options. An obvious example is the `-msoft-float'
|
|||
|
option supported on several processors. This option means that the
|
|||
|
floating point registers are not available, which means that floating
|
|||
|
point operations must be done by calling an emulation subroutine rather
|
|||
|
than by using machine instructions.
|
|||
|
|
|||
|
For such options, gcc is often configured to compile target libraries
|
|||
|
twice: once with `-msoft-float' and once without. When gcc compiles
|
|||
|
target libraries more than once, the resulting libraries are called
|
|||
|
"multilibs".
|
|||
|
|
|||
|
Multilibs are not really part of the GNU configure and build system,
|
|||
|
but we discuss them here since they require support in the `configure'
|
|||
|
scripts and `Makefile's used for target libraries.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Multilibs in gcc:: Multilibs in gcc.
|
|||
|
* Multilibs in Target Libraries:: Multilibs in Target Libraries.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Multilibs in gcc, Next: Multilibs in Target Libraries, Up: Multilibs
|
|||
|
|
|||
|
8.1 Multilibs in gcc
|
|||
|
====================
|
|||
|
|
|||
|
In gcc, multilibs are defined by setting the variable
|
|||
|
`MULTILIB_OPTIONS' in the target `Makefile' fragment. Several other
|
|||
|
`MULTILIB' variables may also be defined there. *Note The Target
|
|||
|
Makefile Fragment: (gcc)Target Fragment.
|
|||
|
|
|||
|
If you have built gcc, you can see what multilibs it uses by running
|
|||
|
it with the `-print-multi-lib' option. The output `.;' means that no
|
|||
|
multilibs are used. In general, the output is a sequence of lines, one
|
|||
|
per multilib. The first part of each line, up to the `;', is the name
|
|||
|
of the multilib directory. The second part is a list of compiler
|
|||
|
options separated by `@' characters.
|
|||
|
|
|||
|
Multilibs are built in a tree of directories. The top of the tree,
|
|||
|
represented by `.' in the list of multilib directories, is the default
|
|||
|
library to use when no special compiler options are used. The
|
|||
|
subdirectories of the tree hold versions of the library to use when
|
|||
|
particular compiler options are used.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Multilibs in Target Libraries, Prev: Multilibs in gcc, Up: Multilibs
|
|||
|
|
|||
|
8.2 Multilibs in Target Libraries
|
|||
|
=================================
|
|||
|
|
|||
|
The target libraries in the Cygnus tree are automatically built with
|
|||
|
multilibs. That means that each library is built multiple times.
|
|||
|
|
|||
|
This default is set in the top level `configure.in' file, by adding
|
|||
|
`--enable-multilib' to the list of arguments passed to configure when
|
|||
|
it is run for the target libraries (*note Host and Target Libraries::).
|
|||
|
|
|||
|
Each target library uses the shell script `config-ml.in', written by
|
|||
|
Doug Evans, to prepare to build target libraries. This shell script is
|
|||
|
invoked after the `Makefile' has been created by the `configure'
|
|||
|
script. If multilibs are not enabled, it does nothing, otherwise it
|
|||
|
modifies the `Makefile' to support multilibs.
|
|||
|
|
|||
|
The `config-ml.in' script makes one copy of the `Makefile' for each
|
|||
|
multilib in the appropriate subdirectory. When configuring in the
|
|||
|
source directory (which is not recommended), it will build a symlink
|
|||
|
tree of the sources in each subdirectory.
|
|||
|
|
|||
|
The `config-ml.in' script sets several variables in the various
|
|||
|
`Makefile's. The `Makefile.in' must have definitions for these
|
|||
|
variables already; `config-ml.in' simply changes the existing values.
|
|||
|
The `Makefile' should use default values for these variables which will
|
|||
|
do the right thing in the subdirectories.
|
|||
|
|
|||
|
`MULTISRCTOP'
|
|||
|
`config-ml.in' will set this to a sequence of `../' strings, where
|
|||
|
the number of strings is the number of multilib levels in the
|
|||
|
source tree. The default value should be the empty string.
|
|||
|
|
|||
|
`MULTIBUILDTOP'
|
|||
|
`config-ml.in' will set this to a sequence of `../' strings, where
|
|||
|
the number of strings is number of multilib levels in the object
|
|||
|
directory. The default value should be the empty string. This
|
|||
|
will differ from `MULTISRCTOP' when configuring in the source tree
|
|||
|
(which is not recommended).
|
|||
|
|
|||
|
`MULTIDIRS'
|
|||
|
In the top level `Makefile' only, `config-ml.in' will set this to
|
|||
|
the list of multilib subdirectories. The default value should be
|
|||
|
the empty string.
|
|||
|
|
|||
|
`MULTISUBDIR'
|
|||
|
`config-ml.in' will set this to the installed subdirectory name to
|
|||
|
use for this subdirectory, with a leading `/'. The default value
|
|||
|
shold be the empty string.
|
|||
|
|
|||
|
`MULTIDO'
|
|||
|
`MULTICLEAN'
|
|||
|
In the top level `Makefile' only, `config-ml.in' will set these
|
|||
|
variables to commands to use when doing a recursive make. These
|
|||
|
variables should both default to the string `true', so that by
|
|||
|
default nothing happens.
|
|||
|
|
|||
|
All references to the parent of the source directory should use the
|
|||
|
variable `MULTISRCTOP'. Instead of writing `$(srcdir)/..', you must
|
|||
|
write `$(srcdir)/$(MULTISRCTOP)..'.
|
|||
|
|
|||
|
Similarly, references to the parent of the object directory should
|
|||
|
use the variable `MULTIBUILDTOP'.
|
|||
|
|
|||
|
In the installation target, the libraries should be installed in the
|
|||
|
subdirectory `MULTISUBDIR'. Instead of installing
|
|||
|
`$(libdir)/libfoo.a', install `$(libdir)$(MULTISUBDIR)/libfoo.a'.
|
|||
|
|
|||
|
The `config-ml.in' script also modifies the top level `Makefile' to
|
|||
|
add `multi-do' and `multi-clean' targets which are used when building
|
|||
|
multilibs.
|
|||
|
|
|||
|
The default target of the `Makefile' should include the following
|
|||
|
command:
|
|||
|
@$(MULTIDO) $(FLAGS_TO_PASS) DO=all multi-do
|
|||
|
This assumes that `$(FLAGS_TO_PASS)' is defined as a set of
|
|||
|
variables to pass to a recursive invocation of `make'. This will build
|
|||
|
all the multilibs. Note that the default value of `MULTIDO' is `true',
|
|||
|
so by default this command will do nothing. It will only do something
|
|||
|
in the top level `Makefile' if multilibs were enabled.
|
|||
|
|
|||
|
The `install' target of the `Makefile' should include the following
|
|||
|
command:
|
|||
|
@$(MULTIDO) $(FLAGS_TO_PASS) DO=install multi-do
|
|||
|
|
|||
|
In general, any operation, other than clean, which should be
|
|||
|
performed on all the multilibs should use a `$(MULTIDO)' line, setting
|
|||
|
the variable `DO' to the target of each recursive call to `make'.
|
|||
|
|
|||
|
The `clean' targets (`clean', `mostlyclean', etc.) should use
|
|||
|
`$(MULTICLEAN)'. For example, the `clean' target should do this:
|
|||
|
@$(MULTICLEAN) DO=clean multi-clean
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: FAQ, Next: Index, Prev: Multilibs, Up: Top
|
|||
|
|
|||
|
9 Frequently Asked Questions
|
|||
|
****************************
|
|||
|
|
|||
|
Which do I run first, `autoconf' or `automake'?
|
|||
|
Except when you first add autoconf or automake support to a
|
|||
|
package, you shouldn't run either by hand. Instead, configure
|
|||
|
with the `--enable-maintainer-mode' option, and let `make' take
|
|||
|
care of it.
|
|||
|
|
|||
|
`autoconf' says something about undefined macros.
|
|||
|
This means that you have macros in your `configure.in' which are
|
|||
|
not defined by `autoconf'. You may be using an old version of
|
|||
|
`autoconf'; try building and installing a newer one. Make sure the
|
|||
|
newly installled `autoconf' is first on your `PATH'. Also, see
|
|||
|
the next question.
|
|||
|
|
|||
|
My `configure' script has stuff like `CY_GNU_GETTEXT' in it.
|
|||
|
This means that you have macros in your `configure.in' which should
|
|||
|
be defined in your `aclocal.m4' file, but aren't. This usually
|
|||
|
means that `aclocal' was not able to appropriate definitions of the
|
|||
|
macros. Make sure that you have installed all the packages you
|
|||
|
need. In particular, make sure that you have installed libtool
|
|||
|
(this is where `AM_PROG_LIBTOOL' is defined) and gettext (this is
|
|||
|
where `CY_GNU_GETTEXT' is defined, at least in the Cygnus version
|
|||
|
of gettext).
|
|||
|
|
|||
|
My `Makefile' has `@' characters in it.
|
|||
|
This may mean that you tried to use an autoconf substitution in
|
|||
|
your `Makefile.in' without adding the appropriate `AC_SUBST' call
|
|||
|
to your `configure' script. Or it may just mean that you need to
|
|||
|
rebuild `Makefile' in your build directory. To rebuild `Makefile'
|
|||
|
from `Makefile.in', run the shell script `config.status' with no
|
|||
|
arguments. If you need to force `configure' to run again, first
|
|||
|
run `config.status --recheck'. These runs are normally done
|
|||
|
automatically by `Makefile' targets, but if your `Makefile' has
|
|||
|
gotten messed up you'll need to help them along.
|
|||
|
|
|||
|
Why do I have to run both `config.status --recheck' and `config.status'?
|
|||
|
Normally, you don't; they will be run automatically by `Makefile'
|
|||
|
targets. If you do need to run them, use `config.status --recheck'
|
|||
|
to run the `configure' script again with the same arguments as the
|
|||
|
first time you ran it. Use `config.status' (with no arguments) to
|
|||
|
regenerate all files (`Makefile', `config.h', etc.) based on the
|
|||
|
results of the configure script. The two cases are separate
|
|||
|
because it isn't always necessary to regenerate all the files
|
|||
|
after running `config.status --recheck'. The `Makefile' targets
|
|||
|
generated by automake will use the environment variables
|
|||
|
`CONFIG_FILES' and `CONFIG_HEADERS' to only regenerate files as
|
|||
|
they are needed.
|
|||
|
|
|||
|
What is the Cygnus tree?
|
|||
|
The Cygnus tree is used for various packages including gdb, the GNU
|
|||
|
binutils, and egcs. It is also, of course, used for Cygnus
|
|||
|
releases. It is the build system which was developed at Cygnus,
|
|||
|
using the Cygnus configure script. It permits building many
|
|||
|
different packages with a single configure and make. The
|
|||
|
configure scripts in the tree are being converted to autoconf, but
|
|||
|
the general build structure remains intact.
|
|||
|
|
|||
|
Why do I have to keep rebuilding and reinstalling the tools?
|
|||
|
I know, it's a pain. Unfortunately, there are bugs in the tools
|
|||
|
themselves which need to be fixed, and each time that happens
|
|||
|
everybody who uses the tools need to reinstall new versions of
|
|||
|
them. I don't know if there is going to be a clever fix until the
|
|||
|
tools stabilize.
|
|||
|
|
|||
|
Why not just have a Cygnus tree `make' target to update the tools?
|
|||
|
The tools unfortunately need to be installed before they can be
|
|||
|
used. That means that they must be built using an appropriate
|
|||
|
prefix, and it seems unwise to assume that every configuration
|
|||
|
uses an appropriate prefix. It might be possible to make them
|
|||
|
work in place, or it might be possible to install them in some
|
|||
|
subdirectory; so far these approaches have not been implemented.
|
|||
|
|
|||
|
|
|||
|
File: configure.info, Node: Index, Prev: FAQ, Up: Top
|
|||
|
|
|||
|
Index
|
|||
|
*****
|
|||
|
|
|||
|
|