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

FL381 - Overview

• 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.

FL381 - Details

• 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."