XPCOM

Welcome to the XPCOM page. This area is intended to be a central clearinghouse for information related to XPCOM. Currently, XPCOM documentation is spread all over mozilla.org. Hopefully, it will migrate (or we'll link to it from) here.

Topics of Interest

• Roadmap for XPCOM, XPConnect, XPTCall, and XPIDL describes how they all fit together
• Modularization Techniques describes XPCOM and how to use it.
• Some COM Ownership Guidelines gives a brief set of guidelines to help you build a supportable ownership model.
• nsCOMPtr User Manual describes a `smart-pointer' class for XPCOM. Check out The nsCOMPtr Home Page for more documentation.
• nsString Proposal proposes a string class for XPCOM.
• mozIRegistry describes the "registry" interface and how you can use it to dynamically bind to interface implementations
• Generic Factories reference document for Generic Factories.
• A Reference Implementation of QueryInterface shows one good way to implement QueryInterface().
• nsISupport Proxies describes how to use thread-crossing XPCOM proxies.
• XPCOM code FAQ has common questions from people implementing XPCOM components
• Rules we break lists and comments on xpcom rules being broken in our codebase
• XPCOM Brown Bag 1 (August 17 1999) [NEW]

• XPConnect describes how XPCOM based classes can be accessed through JavaScript.
• XPIDL is the XP Interface Description Language used to specify XPCOM interface classes
  • XPIDL syntax
  • XPIDL Author's guide

• xptcall is a library that supports invoking methods on arbitrary xpcom objects and implementing classes whose objects can impersonate an xpcom interface
  • porting status lists the currently supported platforms. There are currently many platforms that we need help on.
  • porting guide describes the assembly code that is needed to implement xptcall

• Type Library Format describe the type libraries (.xpt files) that are binary representations of XPCOM interfaces
  • Tools for Typelibs - xpt_dump dumps the information in a typelib to the screen and xpt_link merges typelib files

See Also

• Essential COM by Don Box hardcopy book that explains the rationale behind COM's design
• The nsCOMPtr Home Page.
• C++ portability guide general guidelines for writing portable code