Configuration files can be used by the command-line utilities and Flex Builder compilers.

Flex includes a default configuration file named flex-config.xml. This configuration file contains most of the default compiler settings for the application and component compilers. You can customize this file or create your own custom configuration file.

Flex SDK includes the flex-config.xml file in the flex_install_dir/frameworks directory.

The Flex Builder compilers do not use a flex-config.xml file by default. The default settings are stored internally. You can, however, create a custom configuration file and pass it to the Flex Builder compilers by using the load-config option. Flex Builder includes a copy of the flex-config.xml file that you can use as a template for your custom configuration file. This file located in the flex_builder_install_dir/sdks/sdk_version/frameworks directory.

You can generate a configuration file with the current settings by using the dump-config option, as the following example shows:

mxmlc -dump-config myapp-config.xml