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ABAPPERFORM_PARAMETERS - PERFORM PARAMETERS

ABAPPERFORM_PARAMETERS - PERFORM PARAMETERS

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PERFORM, parameter_list

Short Reference



... $[TABLES   itab1 itab2 ...$]
    $[USING    a1 a2 ...$]
    $[CHANGING a1 a2 ...$].

Additions

1. ... TABLES itab1 itab2 ...

2. ... USING a1 a2 ...

3. ... CHANGING a1 a2 ...

Effect

These additions assign actual parameters to the formal parameters of the parameter interface of the subroutine subr. All data objects whose data type matches the typing of the corresponding formal parameter can be specified (see Check Typing) as actual parameters. Each formal parameter assumes all the properties of the actual parameter assigned to it when it is called. The order of the additions is fixed.

Note

A system field should never be used an actual parameter.

Addition 1

... TABLES itab1 itab2 ...

Effect

The addition TABLES must be used to assign an internal table itab as an actual parameter to each table parameter t1 t2 ... defined for the called subroutine using the addition TABLES of the statement FORM. The assignment of the actual parameters to the formal parameters takes place using their positions in the lists t1 t2 ... and itab1 itab2 ...

Only standard tables can be specified for itab. The data is passed by reference. If a specified table itab has a header line, this is also passed. Otherwise, the header line in the corresponding table parameter t is initial when it is called.

Note

The use of table parameters in the interface of subroutines is obsolete, but a large number of subroutines have not yet been switched to appropriately typed USING parameters or CHANGING parameters and must still be filled by the addition TABLES of the statement PERFORM.

Example

Static call of the internal subroutine select_sflight while passing a table parameter.

Addition 2

... USING a1 a2 ...

Addition 3

... CHANGING a1 a2 ...

Effect

If the additions USING and CHANGING are specified, a type-specific actual parameter a1 a2 ... must be assigned to each of the formal parameters u1 u2 ... and c1 c2 ... defined for the called subroutine using the identically named additions of the statement FORM. The actual parameters specified after USING and CHANGING form one single shared list. They are assigned to the formal parameters in accordance with the position in the shared list. The type of parameter passing is defined by the additions USING and CHANGING in the statement FORM. The addition USING must be in front of CHANGING. Otherwise, the assignment of the actual parameters to the additions USING and CHANGING is ignored by the statement PERFORM. It is also irrelevant whether only one or both of the additions are specified.

Notes

  • For program documentation purposes, it is best to specify the additions USING and CHANGING in the statement FORM in accordance with the definition of the parameter interface.
  • No substring access is possible to an actual parameter of type string or xstring specified after USING or CHANGING.
  • Upcasts are not possible when passing an actual parameter to a USING parameter typed as a reference variable.
  • A USING parameter declared for pass by reference behaves in the same way as a CHANGING parameter, which means that the content of the actual parameter could be changed in a forbidden way.

Example

The following five PERFORM statements mean the same but only the fourth is recommended, since it is the only one that documents the interface of the called subroutine.






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