User Guide

390 Chapter 21 Building Custom CFXAPI Tags
What Are CFX Tags?
CFX tags are custom tags written against the ColdFusion Extension Application
Programming Interface. Generally, you create a CFX if you want to do something that
is not possible in CFML, or if you want to improve performance of a repetitive task.
CFXs can do the following:
• Handle any number of custom attributes.
• Use and manipulate ColdFusion queries for custom formatting.
• Generate ColdFusion queries for interfacing with non-ODBC based information
sources.
• Dynamically generate HTML to be returned to the client.
• Set variables within the ColdFusion application page from which they are called.
• Throw exceptions that result in standard ColdFusion error messages.
You can build CFXs using C++ or Java.
Note
To use a CFX, you must register it in the ColdFusion Administrator, as described in
“Registering CFXs” on page 404.