How to call a FM for a BEx Variable
I have created a BEx Variable of type Customer Exit called 'ZCA8764'
I intend to actually automatically calculate the number of days in the month.
Through some discussions here, I found that I can use a FM NUMBER_OF_DAYS_PER_MONTH_GET
So, I went to CMOD.
But there onwards, I don`t know how to write a code to link the Variable and the FM.
Can someone please advice with a sample code ?
Can someone please assist.