Along with registering your package(s) of custom functions with the Function Call Manager, the registerFunctionCall method is also used to specify a version number for each function that you create. In the previous example, the ConvertDate function is registered with the version number 0x01000300.
Assigning a version number to each function allows you to provide upgrades to single functions in extensions you have already distributed to users.
For example, if you distributed an extension containing a package of 50 functions for your application and then wanted to change the behavior of one of the functions, you could:
- Write a new extension containing just the upgraded function.
- Register the new function using registerFunctionCall, with the same package name and function name as the original function but with a higher version number.
- Distribute the new extension to users.
When the API initializes all of the extensions it would find two functions with the same package name and function name. It would deregister the one with the lower version number thereby updating your application.
Parent topic: Registering your packages of custom functions with the Function Call Manager