When implementing an enhancement, sometimes we need to read a field defined in the main program but which is not available in the enhancement point.
There is a technique which allows us the read the field if it is available in the ABAP stack.
Like for example (please refer to below screenshot), the field ‘TVAK-FPART’ is available in the main program ‘SAPMV45A’, however if the field is not available in the subroutine ‘VBAK_FUELLEN’ (program SAPFV45K) we can still access the field from the ABAP stack using the field symbol technique.
 
Please find below a sample source code how to read data from the ABAP stack:

*Data Declarations:
*Constants.
CONSTANTS:
  lc_stack_loc(20) TYPE c VALUE '(SAPMV45A)TVAK-FPART'.

 *Field Symbols.
FIELD-SYMBOLS: <fs_stackvalue> TYPE ANY.

 *If we have been able to read the required data
*from ABAP stack, proceed.
ASSIGN (lc_stack_loc) TO <fs_stackvalue>.

 IF sy-subrc EQ 0
AND <fs_stackvalue> IS NOT INITIAL.

 * Write the value read from ABAP stack.
  WRITE <fs_stackvalue>.

 ENDIF.
 
 
Serkan AKKAVAK
Computer Engineer
ABAP Developer & SAP MM SD Consultant
Contact : serkurumsal@yandex.com