Internal Tables as Interface Parameters 

Like other data objects, you can pass internal tables by value or reference to the parameter interface  of procedures. If an internal table has a header line, you must indicate that you want to address the body of the table by placing two square brackets ([]) after the table name.

You can define the formal parameters of the parameter interfaces of procedures as internal tables. For typing purposes, the generic table types can also be used, in addition to the generic data types provided.

To ensure compatibility with previous releases, you can also specify formal parameters in subroutines and function modules as TABLESparameters. This defines a formal parameter as a standard table with default key and header line. Whenever you pass a table without a header line as an actual parameter to a formal parameter with a header line (TABLES), the system automatically creates the corresponding header line in the routine.