SAP Function Modules

SAP function modules are sections of ABAP code which can be re-used in any SAP program. 

They generally consist of a number of inputs where you can pass values to the function and a number of outputs which return the calculated value or values back to the calling program. 

While developing your bespoke SAP applications you can create your own FM's to perform specific functionality you may wish to reuse but there are also thousands which have already been created by SAP. Many of these actually perform very usful functionality such as simple date caltulations, more complex transaction specific functionality as well as report creation using the ALV reporting function modules. 

POPUP_TO_CONFIRM 
Display pop box to confirm an action 

0C10_GET_VALID_AUARTS 
0C10 GET VALID AUARTS 

0AIB_CHECK_MAIN 
0AIB CHECK MAIN 

ABAP_DOCU_SHOW 
Display ABAP Keyword Documentation 

ABAP_DOCU_START 
Initial Screen for ABAP Documentation, Search, and Display 

ABL_MOVE_REQUIRED_LENGTH 
Required length for MOVE to a type C target field 

ACTION_CODE_TO_REP_OBJ 
To convert the action code to screen number 

C160_TRANSACTION_CALL 
Call sap transaction code and skip authorisation check?? 

SAP Reports 
Available SAP ABAP Reports