86 lines
4.4 KiB
Plaintext
86 lines
4.4 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@@sourceware.cygnus.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,
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support, and aggregation of useful utilities. There is nothing
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(software-wise) in there that you can't already get off the net
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already, if you take the time to find and download everything (and
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usually, build it yourself). We test it all to make sure it works
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together, and package it in a convenient form. We consider such
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testing and packaging to be a valuable service and thus charge a fee
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for it. Plus, it provides income for the cygwin project so we can
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continue working on it :-)
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@section A brief 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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