The meaning of "External" linking mode in Flex Builder

Question

There are three modes to link an SWC library to a flex application: "Merged into code", "External" and "RSL". I understand what is "RSL", but I don't understand what is "External".

"RSL" works just fine for me, without any code changes. However, External doesn't work for me. Although my application starts, the classes in the SWC set to External are never found.

What is the meaning of "External" if it is not "RSL" ? How do I make use of that ?

Thank you, Boris

Answer 1

Defining a class as External allows the Flex compiler to link to a particular class at compile time but does not cause it to be included in the generated SWF.

The general use for External classes is where you have multiple modules that use a shared library. It would be redundant to include the shared class definitions in every single module and the External keyword allows you to control how these classes are compiled into your libraries.

More information is available at the following locations:

http://web.archive.org/web/20101007120528/http://www.wannaknowflex.com/2010/05/flex-linkage-difference-between-rsl-and-external/

http://www.flexafterdark.com/docs/Flex-Libraries

(external-library-path and load-externs compiler information):
http://www.newtriks.com/?p=802