How to find if is constant or variable in perform using

[former_member605430]

Hi,

i need to check in a perform if the value is coming from constants or variable.

How can i check this?

Example:

data: variable(5).
start-of-selection.
perform test1 using variable.
perform test1 using space.

form test1 using p_to_change.
"only when it is called with variable
"how can I do this?
  p_to_change = 'X'.
endform. 
 

[matt]

You can't. But why do you need to? (Incidentally, your DATA statement is using an obsolete form, and FORMs are also obsolete and shouldn't be used in new programs).

[former_member605430]

I've semplified that, but it's a standard code that use this type of statement.

I'm trying to catch that because i need to change the value if it's from the constant.

Maybe is there a chance to check the properties of the passed field?

thanks

[matt]

So apparently you can! 🙂

[Sandra_Rossi]

Please use the COMMENT button to reply to someone's answer. ANSWER is only to propose a solution. You also have an option to convert your answer into a comment.

[Sandra_Rossi]

If the variable is modifiable in the calling procedure and the parameter is passed by reference (fits your case), then you may differentiate the two cases by checking the read-only flag of the parameter via RTTI:

IF abap_true = CL_ABAP_DATADESCR=>IS_READ_ONLY( p_data = ref #( p_to_change ) ).
  " constant (or read-only variable)
ENDIF.

[former_member605430]

Solved. It works, thanks Sandra.

Results:

1

2.

Example:

DATA: variable(5),
      var2.
START-OF-SELECTION.
  PERFORM test1 USING variable.
  PERFORM test1 USING space.
*&---------------------------------------------------------------------*
*&      Form  test1
*&---------------------------------------------------------------------*

FORM test1 USING p_to_change.
  IF abap_true = cl_abap_datadescr=>is_read_only( p_data = REF #( p_to_change ) ).
    " constant (or read-only variable)
    WRITE:/ '2'.
  ELSE.
    WRITE:/ '1'.
  ENDIF.
ENDFORM.                    "test1