<html> <head> </head> <body> <div class="h2 app" style="border-left: 0px" id="customcontent"> <h2>What is SCons?</h2> <p>SCons is a next-generation, cross-platform, build tool. Think of SCons as an improved substitute for the classic <tt>Make</tt> utility with integrated functionality similar to <tt>autoconf</tt>/<tt>automake</tt> and compiler caches such as <tt>ccache</tt>. </p> <p> Unlike build tools that invent their own mini-language or wedge a scripting language onto some other configuration file syntax, SCons configuration files are actually Python scripts. The ability to script your build gives you a tremendous amount of flexibility to solve complicated build problems in surprisingly small amounts of maintainable code. </p> <p> In short, SCons is an easier, more reliable and more flexible way to build software. </p> <!-- <h2><b>Goal</b></h2> <p>The primary goal of The SCons Project is to become the premiere enterprise-quality tool for building cross-platform, multi-language software projects by offering unparalleled <b>reliability</b> and <b>flexibility</b> to software buildmasters and developers. </p> <p> Yeah, yeah, every project has similar lofty mom-and-apple-pie goals, blah, blah, blah... So why is SCons any different? Fair question. If you go to our public home page at <a href="http://www.scons.org/">http://www.scons.org</a> you'll get the usual lists of supported features and platforms, testimonials, etc. But you're presumably at <emphasis>this</emphasis> project page because you're interested in digging a little deeper. So here are the <emphasis>philosophical viewpoints</emphasis> that we think contribute to SCons being a really distinctive software build tool: </p> <ul> <li> <strong>Software builds are getting more complicated, not less</strong> <p> The proliferation of programming languages and technologies have led to increasingly difficult demands being placed on traditional software build tools Make. EVen if you stick to one language--a well-worn and mature one like C, for example--the differences between the various C tool chains and how they behave on various platforms make it a real challenge to keep your software builds simple and reliable. </p> <p> Consequently, SCons is a build tool </p> </li> <li> <strong>Effective software building is not a language design issue</strong> <p> There are a lot of build tools out there, and it seems like a new one pops up every week as someone gets the urge to fix some particularly bad build problem that they're facing. Most build tools have, historically, invented some special configuration file format to express dependencies and actions. The problem is that by the time you take care of all of the different ways people you really want to have the flexibility that a scripting language gives: loops, conditionals, real data structures, etc. (It's interesting to note that the Ant community is working hard on adding more scriptability to their XML-based Ant files, and James Duncan Davidson, Ant's creator, is on record as saying that he'd use a scripting language if he were doing it over again.) </p> <p> </p> <p> Note that SCons is not completely pure in this regard. </p> </li> <li> <strong>You want to encapsulate software build complexity so most developers don't even have to think about it</strong> <pp> XXX </pp> </li> <li> <strong>Overall, a reliable build that takes a little longer is cheaper than a fast build that you can't rely on</strong> <p> This one is sometimes tough to swallow, because we all want the build to be as quick as possible when we're in that tight edit-build-debug development cycle. The problem is that if you take shortcuts in how your build tool manages the dependencies, you waste time chasing phantom problems that simply go away because you finally give up and do a <tt>make clean; make</tt>. </p> </li> <li> <strong>Building software in multiple side-by-side variants is crucial in a multi-platform world</strong> <pp> XXX </pp> </li> </ul> --> <h2><b>SCons Features</b></h2> <ul> <li> <strong>Configuration files are Python scripts</strong> <p> This provides much more flexibility for solving difficult build problems than traditional build tools. </p> </li> <li> <strong>Reliable, automatic dependency analysis</strong> <p> C, C++ and Fortran are scanned for dependencies, eliminating the need for a separate <tt>make depend</tt> step or a <tt>make clean</tt> to get all of the dependencies. Avoids the time waste from debugging phantom problems that mysteriously disappear after you <tt>make clean; make</tt>. Easily extended to scan for other languages or file types. </p> </li> <li> <strong>Built-in support for multiple languages</strong> <p> C, C++, D, Java, Fortran, Yacc, Lex, Qt and SWIG. Can also build TeX and LaTeX documents. Easily extended for other languages or file types. </p> </li> <li> <strong>Cross-platform</strong> <p> Known to work on Linux, other POSIX systems (AIX, *BSD, HP/UX, IRIX, Solaris), Windows (NT, 2000, XP), Mac OS X, and OS/2. </p> </li> <li> <strong>Fetch files from SCM systems or central directory trees</strong> <p> Built-in support for SCCS, RCS, CVS, BitKeeper and Perforce. On-disk directory trees can be searched for source files or pre-built target files. </p> </li> <li> <strong>Support for Microsoft Visual Studio .NET and 2005</strong> <p> Generates <tt>.dsp</tt> and <tt>.dsw</tt> files, or <tt>.sln</tt> and <tt>.vcproj</tt> files, from the same build configuration used to build on all platforms. Allows Windows developers to do all the productive point-and-click debugging they're used to without having to maintain a separate build configuration just for Windows. </p> </li> <li> <strong>Reliable detection of file changes using MD5 signatures</strong> <p> Use of traditional file timestamps instead of MD5 can be configured. </p> </li> <li> <strong>Parallel builds</strong> <p> Keeps up to N jobs running simultaneously regardless of directory hierarchy. </p> </li> <li> <strong>Global view of dependencies</strong> <p> Simplifies builds by eliminating multiple passes or reording targets to build everything correctly. </p> </li> <li> <strong>Multi-platform configuration (like <tt>Autoconf</tt>)</strong> <p> Support for finding <tt>#include</tt> files, libraries, functions and <tt>typedef</tt> declarations. </p> </li> <li> <strong>Shared built-file cache</strong> <p> Speeds up multiple builds by allowing developers to share pre-built targets (like <tt>ccache</tt>, but for any type of target file, not just C/C++ compilation). </p> </li> </ul> <!-- <h2></h2> <p>What are the high-level assumptions or ground rules for the project? </p> <p>For example: </p> <ul> <li> we will use programming language X on operating system Y for now. <li>We will, or will not, consider certain functional areas like internationalization, high security, concurrency, etc. The list of functional areas will depend on what you are trying to do. <li>Try to keep this part short. </ul> --> <h2>Future</h2> See the <a href="roadmap.html">Roadmap</a> page. </div> </body> </html>