Data Interfaces

Local Call of Function Modules
ABAP/4 function module ...
Import parameter Reference field Ref. type Proposal Optional Reference
f1 ...
Export parameter Reference field Ref. type Reference
f2 ...
Changing parameter Reference field Ref. type Proposal Optional Reference
f3 ...
Tables parameter Reference field Optional
t1 ...
...
CALL FUNCTION 'TEST'
EXPORTING
f1 = a1
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ABAP/4 program ABAP/4 function module
IMPORTING
f2 = a2
CHANGING
f3 = a3
TABLES
t1 = tab
The function
module is
executed locally
in the same
R/3 System.
FUNCTION TEST.
...
ENDFUNCTION.
In R/3, function modules are ABAP/4 programs which are stored centrally in the Function Library.
They can be called locally by any ABAP/4 program. Function modules are similar to functions in C, and
procedures in PASCAL or COBOL. Both C functions and PASCAL or COBOL procedures are also
stored in a central library.
Function modules have a defined interface. Input parameters are passed to them via the IMPORTING
or CHANGING interface. Single result parameters can be returned via the EXPORTING and
CHANGING interface, but internal tables are passed to the TABLES interface. When creating a
function module, you can define IMPORTING parameters as optional. Since they have a predefined
value, you do not have to assign a value when calling a function module.
Interface parameters should reference Dictionary reference structures.
CHANGING parameters contain fields or field strings which can be passed from the program to the
function module when the function module is called, and returned to the calling program when the
processing of the function module has finished.
For each function module, you can raise exceptions which the function module can trigger if an error
occurs.
You maintain function modules with Transaction SE37.