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ASSIGN - static_dobj

Quick Reference

Other versions: 7.31 | 7.40 | 7.54

Syntax


... dobj[+off][(len)]  ...

Effect

In the static variant for the memory area, a data object dobj with an optional offset/length +off(len) can be specified in accordance with the rules in the section Data Objects in Operand Positions, with the following exception: A data reference dereferenced using the dereferencing operator ->* is specified dynamically. dobj specified using a field symbol, on the other hand, is a static variant.

The memory area is determined by the specified offset/length +off(len) as follows:

  • If no offset/length specification is made, the assigned memory area is the same as the memory area of the data object. The entire data object dobj is assigned to the field symbol, and statements that contain the field symbol in operand positions work with the data object.
  • If an offset/length is specified, the memory area is determined from the memory address of the data object and the offset/length specifications. The general rules for substring accesses apply. If these rules are met, memory outside the dobj field limits can also be addressed. The addressable memory is based on the specification range_spec. If an offset off is specified without a length len, the length of the data object dobj is used implicitly for len. If a field symbol is specified for dobj, to which a memory area is already assigned, the content of the offset length can be negative, as long as the area specified in range_spec is not exited. The following restrictions apply when offsets/lengths are specified:
  • The data type of dobj cannot be string or xstring. This means that len can never be less than or equal to zero.
  • If the name of a data object is specified for dobj and if no explicit RANGE addition is used, no offset off can be specified without the length len. If the name of a field symbol is specified for dobj, its data type must be flat and elementary whenever an offset off is specified without length len.

If the assignment is not successful, no memory area is assigned to the field symbol after the ASSIGN statement. The return code sy-subrc is not set for static variants. Instead, the predicate expression <fs> IS ASSIGNED can be evaluated.

In an inline declaration of the field symbol with FIELD-SYMBOL(<fs>), the field symbol is typed with the data type that can be determined statically for mem_area. If mem_area is a generically typed field symbol or a generically typed formal parameter, the generic type is used.


Notes

  • Ensure that the system field sy-subrc is not evaluated inadvertently after the static variant. The value of the system field in this case is always the same as it was before the ASSIGN statement was executed and therefore does not indicate whether the statement was successful.
  • Even the static variant is dynamic in the sense that the offset and length specifications may be dynamic. Dynamic offset/length specifications do not, however, result in the system field sy-subrc being set.
  • If a generically typed field symbol or a generically typed formal parameter is specified for dobj, its current type at runtime determines the behavior, for example whether offsets/lengths can be specified.


Example

Assigns the memory area of the individual characters of a data object text to a field symbol <char>.

DATA text TYPE c LENGTH 10 VALUE '0123456789'. 

FIELD-SYMBOLS <char> TYPE c. 

DATA off TYPE i. 

DO 10 TIMES. 
  off = sy-index - 1. 
  ASSIGN text+off(1) TO <char>. 
  cl_demo_output=>write_text( |{ <char> }| ). 
ENDDO. 
cl_demo_output=>display( ).

Example

A field symbol <fs1> points to the component col1 of the structure struct. In the first assignment of <fs1> to a field symbol <fs2>, an offset without length is specified, which means that the length 10 of the component col1 is used implicitly. This assignment is not possible, since the assigned memory area is outside of the permitted range. In the second assignment, the permitted memory area is expanded to the full structure using the assignment RANGE and the assignment is successful.

DATA: 
  BEGIN OF struct, 
    col1 TYPE c LENGTH 10 VALUE 'aaaaaaaaaa', 
    col2 TYPE c LENGTH 10 VALUE 'bbbbbbbbbb', 
  END OF struct. 

FIELD-SYMBOLS: <fs1> TYPE c, 
               <fs2> TYPE c. 

ASSIGN struct-col1 TO <fs1>. 
ASSIGN <fs1>+5 TO <fs2>. 
IF <fs2> IS NOT ASSIGNED. 
  cl_demo_output=>write( `No assignment without sufficient RANGE` ). 
ENDIF. 
ASSIGN <fs1>+5 TO <fs2> RANGE struct. 
IF <fs2> IS ASSIGNED. 
  cl_demo_output=>display( `Assignment with sufficient RANGE` ). 
ENDIF.