Exercise 3: Call Function Module 
Prerequisites
You have determined the interface definition of function module RFC_CUSTOMER_GET.
See also:
Evaluating Function Modules Using SAP AssistantProcedure
Call function module RFC_CUSTOMER_GET and fill the internal table CUSTOMER_DATA with output values:
*
* Call function module 'RFC_CUSTOMER_GET'
*
call function 'RFC_CUSTOMER_GET'
exporting
kunnr = kunnr
tables
customer_t = customer_data
exceptions
nothing_specified = 1
no_record_found = 2
others = 3.
if sy-subrc <> 0.
write: / text-001. "Call error !
exit.
endif.
How to Continue
Display R/3 Data