When you compile a project with Flex Builder, you open the Flex compilers from within Flex Builder itself, not from the command line. You can build your projects manually or let Flex Builder automatically compile them for you. In either case, the Flex Builder compiler creates the SWF application files, generates a wrapper, places the output files in the proper location, and alerts you to any errors encountered during compilation. You then run and debug your applications as needed.

If you must modify the default build settings, you have several options for controlling how your projects are built into applications. For example, you can set build preferences on individual projects or on all the projects in your workspace, modify the build output path, change the build order, and so on. You can also create custom build instructions using third-party tools, such as Apache Ant.

When your projects are built, automatically or manually, Flex Builder places the SWF file in the project output folder along with the wrapper. By default, this is the debug version of your application. It contains debugging information and, therefore, is used when you debug your application. A wrapper file embeds the application SWF file and is used to run or debug your application in a web browser. The standard version of your application SWF files, which you generate through Export Release Version, does not include the additional debugging information and is smaller.

Compiling an application that uses modules

In Flex Builder, you create modules as applications and compile them by either building the project or running the application. The result is a SWF file that you load into your application as a module.

You cannot run the module-based SWF file as a stand-alone Flex application or load it into a browser window. It must be loaded by an application as a module. When you run it in Flex Builder to compile it, you should close the Player or browser Window and ignore any errors. Modules should not be requested by the Player or through a browser directly.

For information on compiling modules in Flex Builder, see Creating Modular Applications