Doubt in export, import and table para when creating Function Module

Question

Dear fellow ABAPers,
I have a doubt in defining export, import and table parameter while creating a function module.
I am calling a function module inside a user exit. Now in the user exit the SAP fills an internal table called i_lfa1 with all the data user has eneterd.
Now I want to pass this whole internal table to function module and the perform some checks on the values of internal table.
After that function module fills an error structure with values depending on some check.
1)
How do I pass this internal table to function module ? 
When I am creating function module in se37 where do I define this iternal table type ? Is it in Import or Table parameter during function module creation?
2)
Where do I define error structure type (which is returned by function module to main program)? Is it in Export or table parameter during function module creation?
Please clear my doubt..
Relevant points will be awarded.
Regards,
Tushar.

Answer 1

Hi Tushar,
1. How do I pass this internal table to function module ?
   I assume u are creating your own Y/Z FM.
   Pass it thru TABLES parameter.
2. When I am creating function module in se37 where do I define this iternal table type
   Define this in TABLES interface.
   What Type ?
   THE SAME TYPE WHICH HAS BEEN DEFINED
    WHILE PASSING IN THE USER-EXIT FUNCTION MODULE.
   IF U SEE THE FM OF THE USER-EXIT,
   U WILL COME TO KNOW.
3.
Where do I define error structure type (which is returned by function module to main program)? Is it in Export or table parameter during function module creation?
Define it in TABLES interace. (not in export, import)
  (Since what u are going to return is an internal table)
  U can take for eg. BDCMSGCOLL.
  OR u can create your own Y/Z structure
for the same purpose.
  (or u can use the structure type T100)
I hope it helps.
Regards,
Amit M.