Skip to content

ABAP Keyword Documentation →  ABAP - Reference →  Calling and leaving program units →  Calling Processing Blocks →  Calling procedures →  PERFORM →  PERFORM - general 

PERFORM - subr_identifier

Short Reference

Other versions: 7.31 | 7.40 | 7.54

Syntax


... subr 
  | {subr|(sname) IN PROGRAM [prog|(pname)] [IF FOUND]}
  | {n OF subr1 subr2 ...} ... .

Alternatives

1. ... subr ... .

2. ... subr|(sname) IN PROGRAM [prog|(pname)] [IF FOUND] ... .

3. ... n OF subr1 subr2 ... .

Effect

These names are used to specify subroutines, whereby subr is the name of the subroutine declared in the statement FORM, and prog is the name of an ABAP program. sname and pname are character-like fields that contain the name of a subroutine or a program when a statement is executed.


Note

As well as the alternatives shown here, there is another obsolete form of the external subroutine call.

Alternative 1

... subr ... .

Effect

subr can be used to call any subroutine of the same program. The subroutine must exist.

Alternative 2

... subr|(sname) IN PROGRAM [prog|(pname)] [IF FOUND] ... .

Effect

This specification is used to call any subroutine of another program or the current program. The subroutine and the program can either be specified statically as subr and prog (static external subroutine call), or dynamically in the parenthesized character-like fields sname and pname. When the statement is executed, sname and pname must contain the name of a subroutine or program in uppercase (dynamic external subroutine call).

If the addition IF FOUND is not specified, and the specified subroutine or program is not found, a syntax error occurs if specified statically and an unhandleable exception is raised if specified dynamically.

If the addition IF FOUND is specified and the specified program is not available at runtime, the statement PERFORM is ignored. If IF FOUND is specified, a subroutine declared statically does not have to be available at the time of compilation and is not identified until runtime.

If the specified program is available, it is loaded, if required, into the internal session and scanned for the specified subroutine. The event LOAD-OF-PROGRAM is not triggered. If the subroutine is available, the event LOAD-OF-PROGRAM is triggered (if not already triggered) and then the subroutine is executed.


Notes

  • External calls of subroutines are almost completely obsolete. Instead of subroutines, you can use methods and function modules as explicit functional interfaces of a program.
  • Furthermore, external calls of subroutines are critical, since there is usually no static way of determining which program groups are assigned to the frame program.
  • To call a subroutine in a program of another package, the definition of the subroutine must be shared between a declaration part and an implementation part using the additions DEFINITION and IMPLEMENTATION. The declaration part must be published in the package interface.
  • If no further addition is specified apart from IN PROGRAM (no IF FOUND, no parameter list), the program name can be omitted and is added implicitly with the name of the current program.

Alternative 3

... n OF subr1 subr2 ... .

Effect

This specification selects a subroutine subr of the same program from a list. The list subr1 subr2 ... can contain up to 256 directly specified subroutines. n must be a numerical data object containing a number between 1 and the specified number of subroutines when the statement is executed. The subroutine subr is called, whose list position is in n. In this variant, it is not possible to specify parameter_list and only subroutines without a parameter interface can be called.


Example

This example calls n internal subroutines subr_1 through subr_n successively from a list.

DATA n TYPE i. 

... 

DO n TIMES. 
  PERFORM sy-index OF subr_1 subr_2 ... . 
ENDDO. 

FORM subr_1. 
  ... 
ENDFORM. 

FORM subr_2. 
  ... 
ENDFORM. 

...