Remote Function Calls (RFC) - Introduction

Remote Function Calls allow users to call R/3 function modules or external functions "remotely".
RFC development libraries exist for OS/2, Windows, Windows NT, and for all UNIX platforms supported by SAP. These help you to communicate with external programs (C and C++).
The R/3 Function Builder also contains an RFC generator that you can use to generate external programs and download them onto your frontend system.


In an RFC, a series of tasks is performed automatically:

• Data conversion

• Logon to the SAP partner system

• Conversion of all RFC data types

• Control of the communication flow
  
  
  The following basic conditions apply when you call a function module remotely:
  
  
  The function module that you call must be flagged as "remote". You set this attribute in the Function Builder. Tools -> ABAP Workbench -> Development -> Function Builder. Note that all parameters in a remotely-callable function module must have a reference field.
  
  
  The target must be defined (see Defining remote destinations). To do this, choose Tools → Administration, Administration → Network →RFC destinations.
  You can execute a function module as follows:
  
  Synvhronously:,,CALL FUNCTION func DESTINATION dest
  
  Asynchronously,,CALL FUNCTION func ... STARTING NEW TASK taskname
  
  Transactionally:,,CALL FUNCTION func... IN BACKGROUND TASK
  
  
  In a Remote Function Call, there is an RFC client and an RFC server. The RFC client is the instance that calls the function "remotely". The RFC server provides and executes the function.
  
  
  To ensure that RFC functions are executed on the RFC server regardless of the availablity of the server, you can make the call transactional (see CALL FUNCTION func ... IN BACKGROUND TASK). This buffers the parameters in the R/3 database and they are transferred as a single unit.
  
  
  See also the information about RFC logon to the target system (remote logon), trusted systems, and the RFC authorization concept.
  
  
  Typical problems and their solutions:

• ABAP runtime error: RAISE_EXCEPTION

• Error message CALL_FUNCTION_OBJECT_ID

• No ABAP short dump after failed RFC logon

• SYSTEM_FAILURE: Screen output without connection to user

• RFC destination is incorrect after IP addresses were changed

• RFC logon screen appears

• Short dumps with error ID RFC_NO_AUTHORITY
  
  

Help Documentation

For a comprehensive description of communication interfaces in the SAP environment, refer to Remote Communications.