Record Calls To External Modules
On the Sequence Diagram Recording tab, the Record calls to external modules option causes function calls to external modules outside the model to be included in the sequence history and generated diagram.
For applications built in a Microsoft Native code (C, C++) you can record calls to the WIN32 API if required, using the Record calls to external modules option. This option can also be used to record calls to functions in modules that have a PDB file but for which there is no source.
Only calls originating within the model to functions external to the model are recorded.
External calls are displayed with a blue connector, as shown below.
This example shows three external calls (ToString()) to the Microsoft .NET framework assembly function System.Single.