Difference between exits

Question

hi gurus,
what is the difference between
SD user exits
and
Other user exits

Answer 1

Hi,
User Exit is a common terminology and it is not specific to SD...
User exits are hooks in standard SAP code, which allow you to add functionality. The positioning of these exits has been defined by SAP, so often you can't find one where you need it!
The implementation of user exits depends on the module. Some (and more, as you go to later releases) are implemented using CALL CUSTOMER-FUNCTION (see help documentation for this ABAP statement) - these are controlled from transactions CMOD and SMOD - have a look at the online documentation - transaction CMOD, menu Utilities --> Online Manual.
In older areas of SAP code, the exit might be coded using an empty form supplied by SAP. E.g. look at module SAPMV45A. This has many forms beginning USEREXIT_... You can insert your own code in this.
In other areas such as FI or LIS, there are configuration entries which allow calls to external ABAP code.
Up until 4.5, there are field-exits. These are triggered as the first action during a PAI event. They are linked to a field's domain, and can be made global for that domain, or screen specific.
Finally, you may need to make customer specific changes to SAP code. Note that if you choose to do this, SAP will not support the modified code.
What is User Exits and Customer Exits?
Difference between user exits & customer exits:
User exit - A user exit is a three character code that instructs the system to access a program during system processing.
SXX: S is for standard exits that are delivered by SAP.   XX represents the 2-digit exit number.
UXX: U is for user exits that are defined by the user.  XX represents the 2-digit exit number
Customer exit - The R/3 enhancement concept allows you to add your own functionality to SAP?s standard business applications without having to modify the original applications. SAP creates customer exits for specific programs, screens, and menus within standard R/3 applications. These exits do not contain any functionality. Instead, the customer exits act as hooks. You can hang your own add-on functionality onto these hooks.     *-- Mani
The following document is about exits in SAP :-
The R/3 enhancement concept allows you to add your own functionality to SAP?s standard business applications without having to modify the original applications. 
SAP creates user exits for specific programs, screens, and menus within standard R/3 applications. These exits do not contain any functionality. Instead, the customer exits act as hooks. You can hang your own add-on functionality onto these hooks.
Types of Exits 
There are several different types of user exits. Each of these exits acts as hooks where you can attach or "hang" your own add-ons.
Menu Exits
Menu exits add items to the pulldown menus in standard SAP applications. You can use these menu items to call up your own screens or to trigger entire add-on applications.
SAP creates menu exits by defining special menu items in the Menu Painter. These special entries have function codes that begin with "+" (a plus sign). You specify the menu item?s text when activating the item in an add-on project.
Screen Exits
Screen exits add fields to screens in R/3 applications. SAP creates screen exits by placing special subscreen areas on a standard R/3 screen and calling a customer subscreen from the standard screen?s flow logic.
Function Module Exits 
Function module exits add functions to R/3 applications. Function module exits play a role in both menu and screen exits. 
When you add a new menu item to a standard pull down menu, you use a function module exit to define the actions that should take place once your menu is activated. 
Function module exits also control the data flow between standard programs and screen exit fields. SAP application developers create function module exits by writing calls to customer functions into the source code of standard R/3 programs. 
These calls have the following syntax: 
CALL CUSTOMER-FUNCTION ?001?.
Field Exits
Field exits allow you to create your own programming logic for any data element in the Dictionary. You can use this logic to carry out checks, conversions, or business-related processing for any screen field.  Example: The data element BBBNR identifies a company?s international location number. You might want to set up your R/3 System so that all international location numbers are larger than 100. 
The field exit concept lets you create a special function module that contains this logic. 
You assign the special function module to the data element BBBNR. You then assign the module to any programs and screens in which users can add new international location numbers. When you activate your field exit, the system automatically triggers your special routine whenever a user enters a company location number. 
In 4.6c, you can use "RSMODPRF" program to create field exits.
An example of a user exits :-
MODULE user_exit_0001 INPUT 
    CASE okcode.
        WHEN 'BACK OR EXIT'.
            CASE sy-dynnr.
                    WHEN '100'.
                         SET SCREEN 0.
                         LEAVE SCREEN.
                    WHEN '200'.
Note that you can write any code that satisfy your needs.                                                
But in this case, this was wrote as a sample code for reference sake.                                 
And you can test it                                                                               
SET SCREEN 100.
                         LEAVE SCREEN.
             ENDCASE.
      ENDCASE. 
A Short Tutorial on User Exits
User exits :
1. Introduction
2. How to find user exits
3. Using Project management of SAP Enhancements 
1. Introduction:
User exits (Function module exits) are exits developed by SAP. The exit is implementerd as a call to a functionmodule. The code for the function module is writeen by the developer. You are not writing the code directly in the function module, but in the include that is implemented in the function module.
The naming standard of function modules for functionmodule exits is: 
EXIT_<program name><3 digit suffix> 
The call to a functionmodule exit is implemented as:
CALL CUSTOMER.-FUNCTION <3 digit suffix>
Example:
The program for transaction VA01 Create salesorder is SAPMV45A
If you search for CALL CUSTOMER-FUNCTION i program
SAPMV45A you will find ( Among other user exits):
CALL CUSTOMER-FUNCTION '003'
  exporting
    xvbak   = vbak
    xvbuk   = vbuk
    xkomk   = tkomk
  importing
    lvf_subrc = lvf_subrc
  tables
    xvbfa = xvbfa
    xvbap = xvbap
    xvbup = xvbup.
The exit calls function module EXIT_SAPMV45A_003
2. How to find user exits?
Display the program where you are searching for and exit and search for CALL CUSTOMER-EXIT
If you know the Exit name, go to transaction CMOD.
Choose menu Utillities->SAP Enhancements. Enter the exit name and press enter.
You will now come to a screen that shows the function module exits for the exit.
3. Using Project management of SAP Enhancements, we want to create a project to enahance trasnaction VA01 .
- Go to transaction CMOD
- Create a project called ZVA01
- Choose the Enhancement assign radio button and press the Change button
In the first column enter V45A0002 Predefine sold-to party in sales document. 
Note that an enhancement can only be used in 1 project. If the enhancement is already in use, and error message will be displayed
Press Save
Press Components. You can now see that enhancement uses user exit EXIT_SAPMV45A_002. Double click on the exit.
Now the function module is displayed. Double click on include ZXVVAU04 in the function module
Insert the following code into the include: E_KUNNR = '2155'.
Activate the include program. Go back to CMOD and activate the project. 
Goto transaction VA01 and craete a salesorder. 
Note that Sold-to-party now automatically is "2155"
Hope this helps u..
reward points if helpful
Jgds
Edited by: Jegadesh Balan on Dec 20, 2007 5:00 AM