159 lines
8.0 KiB
Plaintext
159 lines
8.0 KiB
Plaintext
@chapter What is it?
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The Cygwin tools are ports of the popular GNU development tools
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for Windows NT, 95, and 98. They run thanks to the Cygwin library which
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provides the UNIX system calls and environment these programs expect.
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With these tools installed, it is possible to write Win32 console or
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GUI applications that make use of the standard Microsoft Win32 API
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and/or the Cygwin API. As a result, it is possible to easily
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port many significant Unix programs without the need
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for extensive changes to the source code. This includes configuring
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and building most of the available GNU software (including the packages
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included with the Cygwin development tools themselves). Even if
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the development tools are of little to no use to you, you may have
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interest in the many standard Unix utilities provided with the package.
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They can be used both from the bash shell (provided) or from the
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standard Windows command shell.
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@section Is it free software?
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Yes. Parts are GNU software (gcc, gas, ld, etc...), parts are covered
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by the standard X11 license, some of it is public domain, some of
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it was written by Cygnus and placed under the GPL. None of it is
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shareware. You don't have to pay anyone to use it but you should be
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sure to read the copyright section of the FAQ more more information on
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how the GNU General Public License may affect your use of these tools.
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In particular, if you intend to port a proprietary (non-GPL'd)
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application using Cygwin, you will need the proprietary-use license
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for the Cygwin library. This is available for purchase; please
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contact sales@@cygnus.com for more information.
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All other questions should be sent to the project
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mailing list cygwin@@sources.redhat.com.
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Note that when we say "free" we mean freedom, not price. The goal of
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such freedom is that the people who use a given piece of software
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should be able to change it to fit their needs, learn from it, share
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it with their friends, etc. The Cygwin license allows you those
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freedoms, so it is free software.
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The Cygwin 1.0 product is a "commercial" distribution of cygwin. As
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such, it includes such non-software things as printed manuals, support,
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and aggregation of useful utilities. There is nothing (software-wise)
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in there that you can't already get off the net already, if you take the
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time to find and download everything (and usually, build it yourself),
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although the @emph{versions} available for download may be different
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than those distributed with the commercial product. We test it all to
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make sure it works together, and package it in a convenient form. We
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consider such testing and packaging to be a valuable service and thus
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charge a fee for it. Plus, it provides income for the cygwin project so
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we can continue working on it. For further details about the commercial
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product, see @file{http://www.cygnus.com/cygwin/}.
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@section Recent history of the project: What version @emph{is} this, anyway?
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Starting on April 17, 2000, the Cygwin team changed the procedure for
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doing net releases.
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Previously, net releases entailed downloading one or two large files
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(called something like @code{FULL.EXE} or @code{USER.EXE}). These files
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unpacked a "Cygwin Distribution" to a static (and arcane) directory
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structure. This distribution contained lots of .exe, .a, .h, and other
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files.
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These distributions were named after the version of the Cygwin DLL which
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they contained. The last version released with this method was Cygwin
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B20.1.
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This distribution method has the advantage that everything was "all in
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one place". You could copy the huge FULL.EXE file around and know that
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you were getting the complete "Cygwin Distribution".
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The method had several disadvantages, however. 1) it was huge, 2) it
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was hard to download in one error-free piece, and 3) it was hard to
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update.
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Why was it hard to update? Because any change to any package in
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FULL.EXE meant re-generating all of FULL.EXE. This process was not easy
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to automate since FULL.EXE was an InstallShield executable. As a
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result, until recently, Cygwin development was relatively static.
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To rectify these problems, the Cygwin team decided, early in January
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2000, to break up the packages in the release and make a small program
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(@code{setup.exe}) available to use in downloading packages. After much
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development and internal discussion on the cygwin-developers mailing
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list, the new, improved version of a Cygwin release was made available
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on April 17, 2000.
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This new release also had a new version of the Cygwin DLL -- 1.1.0.
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Most of the other packages were updated and some packages from the
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Cygwin CD were included. Meanwhile, the Cygwin DLL continues to be
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updated, and is more generically referred to as "1.1.x".
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Users obtain this package by first downloading a version of
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@code{setup.exe}. This program started as a simple command line tool,
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has metamorphosed into a GUI, and is in the process of continual
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improvement. However, its purpose is simple -- it is designed to
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install packages from the cygwin web site at sources.redhat.com. In
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effect, it is a smaller, more intelligent replacement for FULL.EXE. It
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does not require the downloading a huge executable but rather downloads
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individual small packages.
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Does this mean that the new net release of the Cygwin package is 1.1.x?
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No. We no longer label the releases with the Cygwin version number.
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Each package in the cygwin release has its own version now.
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Does this mean that Cygwin 1.1.x is newer than B20.1? Yes! The cygwin
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1.1.x versions all represent continual improvement in the Cygwin DLL.
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Although the 1.1.x code is still considered "beta quality", the Cygwin
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team felt comfortable enough with the cygwin technology to bump the
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version number to "1".
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The other packages in the latest directory are also continually
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improving, some thanks to the efforts of net volunteers who maintain the
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cygwin binary ports. Each package has its own version numbers and
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its own release process.
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So, how do you get the most up-to-date version of cygwin? Easy. Just
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download the setup.exe program from your closest mirror. This program
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will handle the task of updating the packages on your system to the
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latest version. The Cygwin team frequently updates and adds new
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packages to the soureware web site. The setup.exe program is the
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easiest way to determine what you need on your system.
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@section Ancient history of the project
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The first thing done was to enhance the development tools (gcc, gdb,
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gas, et al) so that they could generate/interpret Win32 native object
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files.
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The next task was to port the tools to Win NT/95. We could have done
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this by rewriting large portions of the source to work within the
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context of the Win32 API. But this would have meant spending a huge
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amount of time on each and every tool. Instead, we took a substantially
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different approach by writing a shared library (cygwin.dll) that adds
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the necessary unix-like functionality missing from the Win32 API (fork,
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spawn, signals, select, sockets, etc.). We call this new interface the
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Cygwin API. Once written, it was possible to build working Win32
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tools using unix-hosted cross-compilers, linking against this library.
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From this point, we pursued the goal of producing native tools capable of
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rebuilding themselves under Windows 95 and NT (this is often
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called self-hosting). Since neither OS ships with standard UNIX
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user tools (fileutils, textutils, bash, etc...), we had to get the
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GNU equivalents working with the Cygwin API. Most of these tools were
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previously only built natively so we had to modify their configure
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scripts to be compatible with cross-compilation. Other than the
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configuration changes, very few source-level changes had to be made.
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Running bash with the development tools and user tools in place,
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Windows 95 and NT look like a flavor of UNIX from the perspective of the
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GNU configure mechanism. Self hosting was achieved as of the beta 17.1
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release.
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After adding Windows 98 support to Cygwin in mid-1998, we added support
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for the native Microsoft libraries in the compiler which allows
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compilation of executables that do not use Cygwin. This is important to
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those people who want to use the tools to develop Win32 applications
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that do not need the UNIX emulation layer.
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