Types of Exits in SAP ABAP: User Exit, Customer Exit, Screen Exit, and Search Help Exit — Complete Guide

Introduction to Exits in SAP ABAP

SAP is a powerful ERP platform that is used by a multitude of companies around the world. One of its strongest attributes is the capability to enhance or modify the standard SAP behaviour without altering the base code. This is done via a process known as "exits".

Knowing the kinds of exits available in SAP ABAP is essential for anyone who is an ABAP developer, functional consultant, or technical architect. If you're planning to implement new business logic features, altering the appearance of your screens, or modifying search options, choosing the correct type of exit makes an important difference between a simple solution and a recurring nightmare.

In this complete guide we'll go over:

• What are exits and why are they important?
• User exit in SAP ABAP
• Customer exit in SAP ABAP
• Screen exit example in SAP ABAP
• Search Help exit in SAP ABAP
• CONVERSION_EXIT_ALPHA_INPUT and CONVERSION_EXIT_ALPHA_OUTPUT
• The difference between EXIT and RETURN in SAP ABAP
• Step-by-step implementation guides

What Are Exits in SAP ABAP?

Exits can be described as already-defined hooks integrated by SAP in function modules, standard programs, and screens. They allow developers to add customized code into the SAP standard process without changing SAP's supplied objects — essential to maintain upgrade compatibility.

There are four main categories:

• User Exits
• Customer Exits (Function Module Exits, Menu Exits, Screen Exits)
• Screen Exits
• Search Help Exits

1. User Exit in SAP ABAP

What Is a User Exit?

A user exit inside SAP ABAP can be described as a subroutine (FORM routine) that SAP has inserted into the standard program. The routine is deliberately left empty and reserved for users to add the logic of their choice. They are named according to the convention of EXIT_* or USEREXIT_*, and are called by SAP's source code by using PERFORM ... IN PROGRAM.

Key Characteristics

• Within SAP standard programs
• Implemented as FORM routines within an include program (usually called Z* or Y*)
• No activation is needed in the SMOD/CMOD transaction
• More loosely structured than customer exits

User Exit TCode in SAP ABAP

To determine user exits for an individual transaction, programmers typically employ the following method:

• Proceed to transaction SE38 or SE80
• Open the standard program for the transaction
• Look for PERFORM statements that include USEREXIT_ as well as EXIT_
• You can also make use of the SMOD transaction to search for enhancement spots

Another very popular transaction Code used to manage user exits within SAP ABAP is CMOD, which is utilized to oversee enhancement projects that link customer and user exits together.

User Exits in SAP ABAP Step by Step

Here's how to create a user exit step by step:

Step 1: Identify the user exit by using SE38 (search for USEREXIT_ in the standard program).

Step 2: Locate the include program to which the FORM routine is added (e.g., MV45AFZZ for Sales Orders in SD).

Step 3: Go to the include by using SE38 and then add your own custom FORM routine:

FORM userexit_save_document.
  " Custom logic before saving a sales order
  IF vbak-auart = 'ZOR'.
    MESSAGE 'Custom order type processing triggered.' TYPE 'I'.
  ENDIF.
ENDFORM.

Step 4: Activate the include program. The exit is now active — no CMOD project required.

2. Customer Exit in SAP ABAP

What Is a Customer Exit?

A customer exit within SAP ABAP provides a more organized and robust exit method as compared to user exits. SAP offers three kinds of customer exits:

• Function Module Exits — Custom logic within function modules
• Menu Exits — Adding customized menu options to SAP's standard menus
• Screen Exits — Custom fields and subscreens added to standard SAP screens

The management of customer exits is done through the Enhancement Framework by using the transactions SMOD (view) as well as CMOD (implement).

Customer Exit vs User Exit in SAP ABAP

Customer Exit Implementation in SAP ABAP — Step by Step

Step 1: Find the Exit via SMOD

Open transaction SMOD and type in an appropriate search phrase (e.g., SAPM* or a known exit name like EXIT_SAPLV60B_001) and then explore the available enhancements.

Step 2: Create a Project in CMOD

Open transaction CMOD, click "Create", and enter an appropriate project name (e.g., ZPROJ_SD01). Add the name of the enhancement from SMOD.

Step 3: Implement the Function Module Exit

Double-click on the function module exit to launch the include. Add your logic:

FUNCTION exit_saplv60b_001.
*"-------------------------------------------------------------------
*" Local Interface:
*"  IMPORTING
*"     VALUE(I_VBELN) TYPE  VBELN_VF
*"  TABLES
*"     T_XVBRP STRUCTURE  VBRP
*"-------------------------------------------------------------------

  " Custom billing logic
  LOOP AT t_xvbrp.
    IF t_xvbrp-matnr IS INITIAL.
      MESSAGE 'Material number is missing in billing item.' TYPE 'W'.
    ENDIF.
  ENDLOOP.

ENDFUNCTION.

Step 4: Activate the Project

Return to CMOD and activate the project. The custom code is now live.

Customer Exit Example in SAP ABAP

A typical customer exit example in SAP ABAP uses EXIT_SAPLMEREQ_010 to check purchase requisitions prior to saving. Another popular example is a CMOD project using the enhancement MEREQ001 for MM purchase order enhancements.

3. Screen Exit in SAP ABAP

What Is a Screen Exit?

A screen exit is a specific kind of customer exit that permits developers to include custom fields and subscreens in standard SAP screens. SAP reserves a subscreen area on the standard screen and lets you plug in your own individual subscreen.

Screen Exit Example in SAP ABAP

Take a look at the enhancement SAPMV45A for Sales Orders (VA01/VA02). SAP offers screen exit areas in the header tabs and item tabs that allow you to display customized fields.

Step 1: Determine the screen exit through SMOD. For instance, the enhancement VEDA0001 has screen exits that are applicable to contracts.

Step 2: Within CMOD, create or open a project and assign the enhancement.

Step 3: Create a custom subscreen (e.g., SAPMZVA45A, screen 9001):

" In the PBO (Process Before Output) module of your custom subscreen:
MODULE pbo_custom_fields OUTPUT.
  " Populate custom fields before display
  zcustom_field = gv_custom_value.
ENDMODULE.

" In the PAI (Process After Input) module:
MODULE pai_custom_fields INPUT.
  " Read custom field input from user
  gv_custom_value = zcustom_field.
ENDMODULE.

Step 4: Assign this subscreen to the screen exit area in the function module exit:

FUNCTION exit_sapmv45a_002.
  " Assign subscreen
  MOVE 'SAPMZVA45A' TO subscreen_prog.
  MOVE '9001'       TO subscreen_no.
ENDFUNCTION.

Step 5: Activate the CMOD project. Navigate to VA01 — your custom subscreen will now appear embedded within the standard Sales Order screen.

4. Search Help Exit in SAP ABAP

What Is a Search Help Exit?

A search help exit in SAP ABAP is a function module assigned to a search help object (F4 help) to alter the default search behavior. It lets you:

• Filter the list of values shown to users
• Include additional selection criteria
• Modify the way values are transferred back to the screen

How to Implement a Search Help Exit

Step 1: Create a function module using the standard interface for search help exits. The function module must have specific parameters defined by SAP.

Step 2: Open transaction SE11, navigate to the search help object, and enter your function module's name in the "Search help exit" field.

Step 3: Implement the logic:

FUNCTION z_sh_exit_customer.
*"-------------------------------------------------------------------
*" Modifies customer search help to show only active customers
*"-------------------------------------------------------------------
  CASE callcontrol-step.
    WHEN 'SELECT'.
      " Add a filter for active customers only
      APPEND INITIAL LINE TO shlp-selopt ASSIGNING FIELD-SYMBOL(<fs_sel>).
      <fs_sel>-shlpfield = 'LIFNR'.
      <fs_sel>-option    = 'NE'.
      <fs_sel>-low       = ''.
    WHEN 'DISP'.
      " Optionally modify display logic
  ENDCASE.

ENDFUNCTION.

5. CONVERSION_EXIT_ALPHA_INPUT and CONVERSION_EXIT_ALPHA_OUTPUT

These are conversion exit function modules used to format values for internal and external representation in SAP.

CONVERSION_EXIT_ALPHA_INPUT in SAP ABAP

CONVERSION_EXIT_ALPHA_INPUT converts an external format (without leading zeros) to internal format (with leading zeros). It is used to pad numbers like vendor numbers, material numbers, etc.

DATA: lv_matnr_ext TYPE matnr VALUE '1234',
      lv_matnr_int TYPE matnr.

CALL FUNCTION 'CONVERSION_EXIT_ALPHA_INPUT'
  EXPORTING
    input  = lv_matnr_ext
  IMPORTING
    output = lv_matnr_int.

" lv_matnr_int = '000000000000001234'

CONVERSION_EXIT_ALPHA_OUTPUT in SAP ABAP

CONVERSION_EXIT_ALPHA_OUTPUT does the reverse — it converts an internal format (with leading zeros) back to external format (without leading zeros) for display purposes.

DATA: lv_matnr_int TYPE matnr VALUE '000000000000001234',
      lv_matnr_ext TYPE matnr.

CALL FUNCTION 'CONVERSION_EXIT_ALPHA_OUTPUT'
  EXPORTING
    input  = lv_matnr_int
  IMPORTING
    output = lv_matnr_ext.

" lv_matnr_ext = '1234'

These function modules follow the conversion exit naming convention CONVERSION_EXIT_<name>_INPUT / _OUTPUT and are automatically called by SAP when fields have a conversion routine defined in the Data Dictionary (SE11).

6. AT EXIT Command in SAP ABAP

The AT EXIT command in SAP ABAP is utilized in module pool and selection screen applications to deal with Back, Exit, and Cancel function codes (F3, F15, F12).

MODULE user_command_0100 INPUT.
  CASE sy-ucomm.
    WHEN 'EXIT' OR 'BACK' OR 'CANCEL'.
      LEAVE TO SCREEN 0.  " Close the screen
    WHEN 'SAVE'.
      PERFORM save_data.
  ENDCASE.
ENDMODULE.

In selection screens, it is utilized together with the AT SELECTION-SCREEN event and the EXIT addition:

AT SELECTION-SCREEN ON EXIT-COMMAND.
  " Called when user clicks Back/Exit/Cancel
  IF sy-ucomm = 'ONLI'.
    LEAVE PROGRAM.
  ENDIF.

7. Difference Between EXIT and RETURN in SAP ABAP

This is among the most frequently asked SAP ABAP interviews question. Here's a concise explanation:

EXIT in SAP ABAP

EXIT is used to instantly leave the current processing block:

• Inside a LOOP: exits the entire loop
• Inside a DO or WHILE: exits the loop
• Inside a SELECT loop: ends the selection loop
• Inside a subroutine called from an exit hook: terminates without error

LOOP AT lt_items INTO ls_item.
  IF ls_item-matnr IS INITIAL.
    EXIT.  " Exits the entire LOOP
  ENDIF.
ENDLOOP.

RETURN in SAP ABAP

RETURN is used to exit the current processing block and return back to the caller:

• In a FORM routine: returns to the calling program
• In a FUNCTION MODULE: returns to the caller
• In a METHOD: returns to the caller

FORM validate_data.
  IF gv_flag IS INITIAL.
    RETURN.  " Exits FORM and returns to caller
  ENDIF.
  " Further logic here
ENDFORM.

Difference Between EXIT and RETURN in SAP ABAP — Summary Table

Best Practices for Using Exits in SAP ABAP

• Always make use of CMOD projects for customer exits — avoid impromptu changes to include programs with no documentation.
• Name your CMOD projects with an appropriate prefix (e.g., ZMMPURCH_01) to make identification easy.
• Beware of performance-heavy logic in frequently called exit routines such as CONVERSION_EXIT routines.
• Record every exit with a header comment including the developer's name, date, ticket number, and purpose.
• Test in the development system prior to transporting exit implementations to quality or production.
• Use CONVERSION_EXIT_ALPHA_INPUT whenever reading material/vendor/customer numbers from external sources (files, BAPIs, IDocs) to avoid key mismatches.
• Prefer BADIs over exits for the latest SAP systems (ECC 6.0+ and S/4HANA) because they provide better OOP-based extensibility.

Frequently Asked Questions

Q: What is the distinction between customer exit and user exit in SAP ABAP?
User exits are FORM routines embedded within SAP standard programs and require manual include edits. Customer exits, however, are much more streamlined and managed through SMOD/CMOD, and can include function module exits, menu exits, as well as screen exits.

Q: How can I find user exits associated with a transaction in SAP?
Use SE38 to launch the standard program and look for USEREXIT_ or PERFORM ... IN PROGRAM. You can also make use of SMOD to search for enhancements by component.

Q: Is it safe to use user exits during SAP upgrades?
Customer exits (CMOD/SMOD) are more secure during upgrades since SAP guarantees the exit interface. User exits based on include modifications carry a greater risk when upgrading.

Q: When should I use CONVERSION_EXIT_ALPHA_INPUT?
Whenever you receive an alphanumeric key (material, vendor, customer) from an external source without leading zeros — always pass it through CONVERSION_EXIT_ALPHA_INPUT before using it in database SELECTs.

Conclusion

Learning the different types of exits available in SAP ABAP — user exits, customer exits, screen exits, and search help exits — is an essential skill for any SAP ABAP developer. Each type of exit serves an exact purpose:

• User exits for quick FORM-based enhancements in standard programs
• Customer exits for structured, upgrade-safe enhancements via CMOD/SMOD
• Screen exits to add custom fields to standard SAP screens
• Search Help exits to personalize F4 value lists
• Conversion exits (ALPHA_INPUT/OUTPUT) to ensure consistency in key formatting

Knowing the distinction between EXIT and RETURN in SAP ABAP and understanding when to use the AT EXIT command can make your applications easier to maintain and cleaner.

Whether you're a beginner following the user exits in SAP ABAP step by step guide or a seasoned consultant working on a customer exit implementation in SAP ABAP, the concepts in this article provide the foundation for extending SAP without breaking standard functionality.

Are you looking to enhance your SAP ABAP skills? Explore our complete SAP ABAP learning path covering BADIs, Enhancement Framework, ALV Reports, Smart Forms, Adobe Forms and many more.