14.3 Calling 3GL Programs / DLLs / Shared Objects
To call an existing 3GL developed DLL or Shared Object under Windows refer to Creating your own Built-In Functions with Visual LANSA.
User defined Built-In Functions are the recommended method of accessing existing 3GL DLL or Shared Objects because:
- The interface between the 3GL object and the RDML function is clearly defined into the LANSA repository.
- The well defined interface is much easier to understand and to use. This aids application developer productivity. For example, Visual LANSA can prompt the developer for the arguments required by the interface.
- The well defined interface is much easier to port to other platforms in the future.
- The well defined interface supports advanced features such as optional arguments, return values and defaults.
- The use of a single well defined interface encourages the reuse of existing facilities and the use of modular design techniques.