# Introduction ## Xalan-C++ Xalan-C++ version is a robust implementation of the W3C Recommendations for [XSL Transformations (XSLT)](http://www.w3.org/TR/xslt) and the [XML Path Language (XPath)](http://www.w3.org/TR/xpath). It works with the [Xerces-C++](http://xerces.apache.org/xerces-c) XML parser. The Xalan-C++ project creates and distributes a standard XSLT library and a simple [`Xalan`](commandline.md) command-line utility for transforming XML documents. This project is written in a reduced set of the C++ programming language. This makes the library directly usable on numerous platforms. A set of 'C' language APIs is also available so that XSLT and XPath functionality is easily deployed to 'C' language applications. [Sample programs](samples.md) are available for you to test and experiment with as you learn the Xalan library. Some of the [EXSLT extension functions](http://www.exslt.org) for XPath are available. We need to write and validate more of the EXSLT functions. A library of [XPath extensions](extensionslib.md) is provided by the Apache Xalan community. Documentation and examples are available for you to write your own custom [XPath extensions](extensions.md). ## Licenses The Xalan-C++ software conforms to The [Apache Software Foundation License, Version 2.0](licensing.md). ## Getting Involved You are invited to participate in [The Apache Software Foundation](http://www.apache.org/foundation/getinvolved.html). You will need to subscribe if you wish to receive mail from the lists. Some lists require a subscription in order to post messages. The *xalan-dev* (`dev@xalan.apache.org`) mailing list is used to communicate product development issues with the software development team. The xalan-dev messages are [archived here](http://mail-archives.apache.org/mod_mbox/xalan-dev) and on [Marc.info](http://marc.info/?l=xalan-dev). The *xalan-c-users* (`c-users@xalan.apache.org`) mailing list is used to discuss issues regarding the use of the Xalan-C++ software and libraries. The xalan-c-users messages are [archived here](http://mail-archives.apache.org/mod_mbox/xalan-c-users) and on [Marc.info](http://marc.info/?l=xalan-c-users). The Git repository changes are logged on the *xalan-commits* mailing list and are [archived here](http://mail-archives.apache.org/mod_mbox/xalan-commits) and on [Marc.info](http://marc.info/?l=xalan-cvs). You can review the project sources and change history in the Git repository on [GitHub](https://github.com/apache/xalan-c) or [Apache GitBox](https://gitbox.apache.org/repos/asf?p=xalan-c.git). You can clone a private copy of the repository using either service. The [JIRA](https://issues.apache.org/jira/projects/XALANC) system is used for issue tracking. You must create an account before you can post messages and files to the JIRA tracking system. You can view the issues at [https://issues.apache.org/jira/projects/XALANC](https://issues.apache.org/jira/projects/XALANC). ## XSLT Standards Implemented Xalan-C++ implements the following specifications from the World Wide Web Consortium (W3C). * [XSL Transformations (XSLT) Version 1.0](http://www.w3.org/TR/xslt) * [XML Path Language (XPath) Version 1.0](http://www.w3.org/TR/xpath) * [Associating Style Sheets with XML documents 1.0 (Second Edition)](http://www.w3.org/TR/xml-stylesheet) The next major release of Xalan-C++ will hopefully be compatible with the following standards: * [XSL Transformations (XSLT) Version 2.0](http://www.w3.org/TR/xslt20) * [XSLT 2.0 and XQuery 1.0 Serialization](http://www.w3.org/TR/xslt-xquery-serialization) * [XML Path Language (XPath) Version 2.0 (Second Edition)](http://www.w3.org/TR/xpath20) * [XQuery 1.0 and XPath 2.0 Formal Semantics (Second Edition)](http://www.w3.org/TR/xquery-semantics) * [XQuery 1.0 and XPath 2.0 Data Model (XDM) (Second Edition)](http://www.w3.org/TR/xpath-datamodel) * [XQuery 1.0 and XPath 2.0 Functions and Operators (Second Edition)](http://www.w3.org/TR/xpath-functions) This added support will require a major version change from 1 to 2. ## XML Parser Library Xalan-C++ uses the The Apache Software Foundation Xerces-C project that implements parsers for XML 1.0 and XML 1.1. The following standards as specified by the [World Wide Web Consortium (W3C)](http://www.w3.org/TR) are implemented by the [Xerces-C++](http://xerces.apache.org/xerces-c) XML parser library: * [Extensible Markup Language (XML) 1.0 (Third Edition) - currently (Fifth Edition)](http://www.w3.org/TR/xml) * [Extensible Markup Language (XML) 1.1 (First Edition) - currently (Second Edition)](http://www.w3.org/TR/xml11) * [xml:id Version 1.0](http://www.w3.org/TR/xml-id) * [XML Base (Second Edition)](http://www.w3.org/TR/xmlbase) * [XML Information Set (Second Edition)](http://www.w3.org/TR/xml-infoset) * [Namespaces in XML 1.0 (Third Edition)](http://www.w3.org/TR/xml-names) * [Namespaces in XML 1.1 (Second Edition)](http://www.w3.org/TR/xml-names11) * [XML Schema Part 1: Structures Second Edition](http://www.w3.org/TR/xmlschema-1) * [XML Schema Part 2: Datatypes Second Edition](http://www.w3.org/TR/xmlschema-2) * [Document Object Model (DOM) Level 1](http://www.w3.org/TR/REC-DOM-Level-1) * [Element Traversal Specification](http://www.w3.org/TR/ElementTraversal) * [Document Object Model (DOM) Level 2 Core Specification](http://www.w3.org/TR/DOM-Level-2-Core) * [Document Object Model (DOM) Level 2 Traversal and Range Specification](http://www.w3.org/TR/DOM-Level-2-Traversal-Range) * [Document Object Model (DOM) Level 3 Core Specification](http://www.w3.org/TR/DOM-Level-3-Core) * [Document Object Model (DOM) Level 3 Validation Specification](http://www.w3.org/TR/DOM-Level-3-Val) * [Document Object Model (DOM) Level 3 Load and Save Specification](http://www.w3.org/TR/DOM-Level-3-LS) * [XML Inclusions (XInclude) 1.0 (Second Edition)](http://www.w3.org/TR/xinclude) Xerces-C++ also supports the [SAX 1.0 and SAX 2.0](http://sax.sourceforge.net/) projects. SAX is primarily Java based. The Xerces-C++ project has implemented a SAX C++ API that looks much like the SAX Java API. Web Services and Web Security recommendations have been developed by the [World Wide Web Consortium (W3C)](http://www.w3.org) and [OASIS-OPEN](http://www.oasis-open.org) Advancing open standards for the information society. Xerces-C++ has support for custom entity resolvers which are inherited and supported by the Xalan-C++ library. ## Security Issues The Xalan-C++ library has hooks so that custom entity resolvers can be deployed. The entity resolvers are actually interfaces into the Xerces-C++ XML Parser Library. Use of trusted entity resolvers greatly increases the security of XML based applications. The Web Services Architecture uses specifications and recommendations that are documented by the following organizations: * World Wide Web Consortium (W3C) [[http://www.w3.org](http://www.w3.org)] * Advancing open standards for the information society (OASIS-OPEN) [[http://www.oasis-open.org](http://www.oasis-open.org)] * The Sourceforge SAX Project (SAX1, SAX2) [[http://sax.sourceforge.net](http://sax.sourceforge.net)] * Internet Engineering Task Force (IETF) [[http://www.ietf.org](http://www.ietf.org)] There are some [architecture security](secureweb.md) issues that should be addressed by any XML parser or XSLT transformation application. Other than validating and cleaning the content of XML elements, the access to untrusted external entities is a big problem for security management. The [`Xalan`](commandline.md) command-line transformation program does not deploy an OASIS catalog or perform other security measures. URLs are resolved using the system directory of the local machine and DNS to resolve host locations. The `Xalan` program should be used only with trusted XSLT stylesheets and XML documents on a trusted computer. A future release of the `Xalan` command-line transformation program may include support for an OASIS entity resolver catalog. Information on creating Secure Web Service Applications is useful for review. This [security overview document](secureweb.md) goes beyond the scope of XSLT transformations and asks many pertinent security based questions. ## Getting Started See the [download](download.md) and [build](build.md) instructions for how to build Xalan-C++ from source. See the [install](install.md) for how to install prebuilt packages for your operating system directly. The current Xalan-C++, Version 1.12, is compatible with the stable releases of [Xerces-C++](http://xerces.apache.org/xerces-c), Version 3.0 and newer. The current stable release for Xerces-C++ is 3.2.3. If you are having problems using the product, send your comments to the *xalan-c-users* (`c-users@xalan.apache.org`) mailing list. If you think a change needs to be made or have suggestions for future releases, send your comments to the *xalan-dev* (`dev@xalan.apache.org`) mailing list.