SAP: Implement a User Exit (Customer Exit) but How?

This is a step by step tutorial that might be useful for a beginners.

Let's suppose you find a suitable customizing activity and it sounds like 'Develop Enhancement for...'
Then you click on the node and what you find is the name of an enhancement, for e.g. DG700004.

• Create an enhancement project

Then you go to transaction CMOD (Enhancements) and create a project in your customer name space
(Z*).

• Create the enhancement assignment

You open the project and go to enhancement assigments. There you can use the previously found enhancement spot DG700004.

• Place your implementation in the enhancement component

In the enhancement components you will find the function exit. It is a function module. EXIT_SAPLDG70_004 in our example.

In the function module there is an include ZX....
You can double click it and after a passing a name space warning, you can type your code.

• Activate the enhancement project

Don't forget to activate your enhancement project.
Place a break-poin and check what happens.

A break-point in the Function MODX_FUNCTION_ACTIVE_CHECK
might help you get to the pont where the enhancement is called, in our case it will be function '004'.