How to create a function module in SAP ABAP

What is function module in sap

Each function module must be attached to one function group. Each contains two include programs by default. One is for global declaration another one is for common subroutines. All the function modules can access the both the include programs.
When ever we are calling any one of the function module then all other function modules will be loaded into the memory of calling program. So it’s better to group related function module into one function group.
Note: – ‘SE37’ is the transaction code function module Tcode in SAP. 

Function group in SAP ABAP

A function group is a collection of function modules that are logically related and share global data. These modules can be executed independently but are often part of a larger, cohesive process. Function groups help in organizing code, making it easier to manage and understand.

How to create function group in SAP ABAP: –

• Execute SE37 is the sap function module Tcode.
• In the menu bar click on GO TO–>Function groups–>Create group(zbbstech_fg).
• Provide the function group name & short description.
• Save. Click on local object.

Steps to activate function group: –

• In the menu bar click on environment–>inactive objects.
• Expand the function group under local objects.
• Select the function group–>Right click on it.
• Click active. Enter.

Components of function module in SAP ABAP: –

1. Attributes
2. Import
3. Export
4. Changing
5. Tables
6. Exceptions
7. Source code

Attributes: –

Attributes specify the type of function module whether it’s a normal or remote enable. If the function module type is normal then we can access the function module within the server only.
If the function module type is remote enable then we can access the function module within the server as well as outside the server also.

Import: –

Import acts like input parameters [using in the server].

Export: –

Export acts like output parameters [changing in the server].

Changing: –

Changing acts like both import & export.

Tables: –

Tables acts like both import & export only for internal tables.

Exceptions: –

These are used to handle the errors in function module.

Source code: –

It contains the logic related function module.

Practice:- Develop a function module to display the all the purchasing order header details based on the given purchasing document number

Steps to create function module: –

• Execute SE37.
• Provide the function module name(zmktao_fm1).
• Click on create.
• Provide the function group name. Provide the short text. Click on save. Enter.
• Click on import.
• Provide parameter name, type, associated type.
• I_EBELN type EKKO-EBELN
• Click on export.
• Provide parameter name, type, associated type.
• E_WA TYPE EKKO
• Click on source code.
• Write source code.
• Select single * from EKKO into E_WA where EBELN = I_EBELN.
• End function.
• Save, check, activate the function module.

Steps to call the function module: –

Place the cursor where you want to call the function module. Click on pattern in the application tool bar. Provide the function module name.

Practice

Based on the given customer numbers, to display the Customer number, customer name and city by developing function module.

Steps to create structure: –

• Execute SE11.
• Select the radio button data type.
• Provide the structure name.
• Click on create.
• Select the radio button structure. Enter.
• Provide the short description.
• Provide component, component type.
• KUNNR KUNNR
• NAME1 NAME1_GP
• ORT01 ORT01_GP
• Save, check, activate.

Steps to create function module: –

• Execute function module Tcode in sap SE37 .
• Provide the function module name(zstwpo_fm2).
• Click on create.
• Provide the function group name. Provide the short text. Click on save. Enter.
• Click on import.
• Provide parameter name, type, associated type.
• I_KUNNR type KNA1-KUNNR
• Click on export.
• Provide parameter name, type, associated type.
• E_WA TYPE ZBBSRT_SKR
• Click on Exceptions.
• Provide Exception name, text.
• Raise Nodata
• Click on source code.
• Write source code.
• Select single KUNNR NAME1 ORT01 from KNA1 into E_WA where KUNNR = I_KUNNR.
• if sy-subrc <> 0.
• Raise Nodata .
• endif.
• Endfunction.
• Save, check, activate the function module.

Steps to call the function module in SAP ABAP: -(SAP SE38)

Place the cursor where you want to call the function module. Click on pattern in the application tool bar. Provide the function module name.

Parameter p_kunnr type kna1-kunnr.
Data wa_kna1 like zsoupa_str.
Call function ‘zstwpo_fm2’
Exporting.
i_kunnr = p_kunnr
Importing
E_wa = WA_KNA1
Exceptions
NODATA = 1
OTHERS = 2.
If SY-SUBRC = 0.
Write: / wa_kna1-kunnr, wa_kna1-name1, wa_kna1-ort01.
Elseif SY-SUBRC = 1.
Write: ‘INVALID INPUT’.
Endif.

Note:

In the function module all parameters are either pass by value or pass by reference. By default all parameters are pass by reference. Pass by reference means from calling to definition & definition to calling all parameter values are passing along with the memory.
Pass by value means from calling to definition & definition to calling only parameters values are passed.

In the remote enable function module all parameters are pass by value only.
Difference.

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