How To Fix W8020 - The interface of function module '&1' does not correspond to conventions

SAP Error Message - Details

• Message type: E = Error

• Message class: W8 - Workflow: Expressions, data flow

• Message number: 020

• Message text: The interface of function module '&1' does not correspond to conventions

What causes this issue?

Function module &VA1& does not correspond to the convention for program
exit for dataflows. The function modules for dataflow have an adjusted
interface which must be as follows:
Import parameters
DATAFLOW with reference SWABINDEF-DATAFLOW
Table parameters
CALLED_CONTAINER with structure SWCONT
CALLING_CONTAINER with structure SWCONT

How to fix this error?

You should adjust the binding function module to accord with this
convention or use the function module SWA_TEMPLATE_EXECUTE_DATAFLOW as
a copy model.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message W8020 - The interface of function module '&1' does not correspond to conventions ?

  Certainly! Here's a detailed explanation for the SAP error message:
  
  SAP Error Message:
  W8020 - The interface of function module '&1' does not correspond to conventions
  
  Cause:
  This warning occurs when a function module's interface does not comply with the expected interface conventions defined by SAP for certain types of function modules. Typically, this happens in the context of Remote Function Calls (RFCs), BAPIs, or other standardized function modules where SAP expects a specific parameter structure, such as:
  
  Importing parameters
  Exporting parameters
  Tables parameters
  Changing parameters
  Exceptions
  
  If the function module interface deviates from these conventions (e.g., missing parameters, wrong parameter types, or incorrect parameter directions), the system issues this warning.
  
  Common scenarios causing W8020:
  
  The function module is intended to be used as an RFC or BAPI but does not follow the required interface pattern.
  The function module is missing the RETURN parameter or has it incorrectly defined.
  The parameter types or names do not match the expected standard.
  The function module is used in a context where SAP expects a certain interface (e.g., BAPI, ALE, IDoc processing), but the interface is inconsistent.
  
  
  Solution:
  
  
  Check the function module interface:
  
  Go to transaction SE37 and display the function module.
  Review the parameters tab and verify that the interface matches the expected conventions.
  
  
  
  Compare with SAP standards:
  
  If the function module is a BAPI, check the BAPI documentation or standard BAPIs for the correct interface.
  For RFCs, ensure the parameters are RFC-compatible (e.g., no complex types that cannot be serialized).
  
  
  
  Adjust the interface:
  
  Add missing parameters such as RETURN (usually a structure of type BAPIRET2).
  Correct parameter types and directions (IMPORTING, EXPORTING, TABLES, CHANGING).
  Ensure that the function module does not have any parameters that violate RFC or BAPI conventions.
  
  
  
  Re-activate the function module:
  
  After making changes, activate the function module.
  
  
  
  Test the function module:
  
  Use SE37 to test the function module.
  If it is an RFC, test remote calls.
  
  
  
  Check related objects:
  
  If the function module is part of a BAPI or ALE interface, check the related object definitions and metadata.
  
  
  
  
  Related Information:
  
  SAP Note: Sometimes SAP provides notes related to specific function modules or interface conventions.
  BAPI Conventions: BAPIs typically require a RETURN parameter of type BAPIRET2 to communicate messages.
  RFC Interface Rules: RFC-enabled function modules must have parameters that are RFC-compatible.
  Transaction SE37: Used to display and maintain function modules.
  Transaction SE80: For object repository and interface management.
  Function Module Documentation: Always check the documentation tab in SE37 for interface guidelines.
  
  
  Summary:
  The warning W8020 indicates that the function module interface does not meet SAP's expected conventions, often related to RFC or BAPI standards. To resolve it, review and correct the function module's parameters to align with SAP's interface requirements.
  
  If you provide the name of the function module (&1 in the message), I can help you with more specific guidance.