Messages have two different functions in function modules and methods:

If you use messages in function modules and methods without the RAISING addition in the MESSAGE statement, and the caller does not catch the message, the message is handled normally according to the context in which it is called within the function module or method.

If you use messages in function modules and methods with the addition

... RAISING <exc>

the way in which the message is handled depends on whether the calling program handles the exception <exc> or not.

• If the calling program does not handle the exception, the message is displayed and handled according to the context in which it occurs in the function module or method from which it was called.
• If the calling program handles the exception, the message is not displayed. Instead, the procedure is interrupted in accordance with the message type, and processing returns to the calling program. The contents of the message are placed in the system fields SY-MSGID, SY-MSGTY, SY-MSGNO, and SY-MSGV1 to SY-MSGV4.

You can catch messages from function modules that are not sent using the RAISING addition in the MESSAGE statement by including the implicit exception ERROR_MESSAGE in the EXCEPTIONS list of the CALL FUNCTION statement. The following conditions apply:

• Type S, I, and W messages are ignored (but logged during background processing)
• Type E and A messages trigger the exception ERROR_MESSAGE
• Type X messages trigger the usual runtime error and short dump.

Catching messages is not currently supported for methods.