How To Fix FL381 - In RFC modules, only parameters with pass by value are allowed

SAP Error Message - Details

• Message type: E = Error

• Message class: FL - Function Builder messages

• Message number: 381

• Message text: In RFC modules, only parameters with pass by value are allowed

What causes this issue?

You have defined a reference parameter for a remotely called function
module. However, only value parameters are allowed in this kind of
function module.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Change the reference parameter to a value parameter.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message FL381 - In RFC modules, only parameters with pass by value are allowed ?

  The SAP error message FL381 indicates that there is an issue with the parameters being passed in a Remote Function Call (RFC) module. Specifically, it states that only parameters that are passed by value are allowed in RFC modules. This error typically arises when a parameter is defined in a way that is incompatible with the RFC interface.
  Cause:
  The primary cause of the FL381 error is the use of parameters that are defined as "pass by reference" in the RFC-enabled function module. In RFC calls, parameters must be passed by value to ensure that the data is correctly transmitted between the calling and called systems. If a parameter is defined as a reference (e.g., a structure or table that is meant to be modified), it will trigger this error.
  Solution:
  To resolve the FL381 error, you need to ensure that all parameters in the RFC-enabled function module are defined as "pass by value." Here are the steps to do this:
  
  
  Check Parameter Definitions: Open the function module in the ABAP Workbench (transaction SE37) and review the parameter definitions. Ensure that all parameters are defined as "Import" or "Export" parameters, and not as "Changing" parameters.
  
  
  Modify Parameter Types: If you find any parameters defined as "Changing" or as reference types, change them to "Import" or "Export" types. This will ensure that they are passed by value.
  
  
  Use Data Types Appropriately: Ensure that you are using appropriate data types for the parameters. For example, if you need to pass a table, consider passing it as an internal table (which is passed by value) rather than a reference to a table.
  
  
  Test the Function Module: After making the necessary changes, activate the function module and test it to ensure that the error is resolved.
  
  
  Related Information:
  
  RFC (Remote Function Call): This is a protocol used in SAP systems to enable communication between different systems or between different instances of the same system.
  Parameter Types: In SAP function modules, parameters can be defined as:
  
  Import: Data is passed into the function module.
  Export: Data is passed out of the function module.
  Changing: Data can be passed in and modified within the function module (not allowed in RFC).
  
  
  ABAP Workbench (SE37): This is the transaction code used to create and manage function modules in SAP.
  
  By following these steps and understanding the underlying principles, you should be able to resolve the FL381 error effectively.