Question

Below is a code snippet that is creating object.

Form userexit_save_document_prepare.
  data: /bks/exitmanager type ref to /bks/exit_manager.
  create object /bks/exitmanager
         exporting main_prog = 'SAPMV45A'
                   exit_form = 'USEREXIT_SAVE_DOCUMENT_PREPARE'.
  include /bks/exitman.
ENDFORM.

I got this from the documentation

For performance reasons, the parameters “main_prog” and “exit_form” should be filled, in the case of userexits, which are performed very often like “user_field_modification” in “SAPMV45A” which is called for every single screen-field.

1) What happened exactly behind when create object /bks/exitmanager is called? memory allocated for the object etc?

2) Why for performance reasons the exporting parameters of create object needs to be filled?

Answer 1

I’m not 100% sure, but here is my best guess:

1. an object called /bks/exitmanager is constructed (which is an oject of the class /bks/exit_manager or more specific a reference/”pointer” to an object of this class) .. the required memory allocated etc., but also the “constructor” code is called (probably sets some instance variables as passed to the call).

2. If you’re explicitly passing these parameters, they don’t have to be “calculated” at run-time (e.g. by looking at the call stack). This should save some time, especially if it would have to be done quite often (as described in the documentation).