If you use the CHECK <expr> statement within an event block 
but not within a loop, and the condition <expr> is not 
fulfilled, the system exits the processing block 
immediately. 

<expr> can be any logical expression or the name of a 
selection table. If you specify a selection table and the 
contents of the corresponding table work are do not fulfill 
the condition in the selection table, it is the same as a 
false logical expression. 


If you use the CHECK <expr> statement within an event block 
but not within a loop, and the condition <expr> is not 
fulfilled, the system exits the processing block 
immediately. 

If the CHECK statement occurs in a loop using DO, WHILE, or 
LOOP, it is the loop that terminates, not the processing 
block. 

A subroutine normally ends at the ENDFORM statement. 
However, you can terminate them earlier by using the EXIT 
or CHECK statement. 
In loop structures like 

DO ... ENDDO
WHILE ... ENDWHILE
LOOP ... ENDLOOP
SELECT ... ENDSELECT


CHECK with a negative outcome terminates the current loop 
pass and goes back to the beginning of the loop to start 
the next pass, if there is one. 

In structures like 

FORM ... ENDFORM
FUNCTION ... ENDFUNCTION
MODULE ... ENDMODULE
AT

CHECK

Conditional termination of a loop pass or a processing block.

Syntax

CHECK <logexp>.

If the logical expression <logexp> is true, the program
continues at the next statement. If, however, <logexp> is
false, the current loop pass terminates and the next begins.
If the program is not currently processing a loop, the
current processing block terminates. There are special forms
of the CHECK statement for use with selection tables and in
GET event blocks.

In loop structures like

DO ... ENDDO
WHILE ... ENDWHILE
LOOP ... ENDLOOP
SELECT ... ENDSELECT


CHECK with a negative outcome terminates the current loop
pass and goes back to the beginning of the loop to start the
next pass, if there is one.

In structures like

FORM ... ENDFORM
FUNCTION ... ENDFUNCTION
MODULE ... ENDMODULE
AT


CHECK with a negative outcome terminates the routine or
modularization unit.

If CHECK is not in a loop or a routine or a modularization
unit, a negative logical expression terminates the current
event. In contrast, the statement REJECT terminates the
current event, even from loops or subroutines.

If a CHECK produces a negative result in a GET event , the
GET events in subordinate tables of the logical database are
not processed either.


CHECK - special for reports with logical databases

1. CHECK sel.
2. CHECK SELECT-OPTIONS.

CHECK sel.

Effect
Checks the selection criterion requested by the statement
SELECT-OPTIONS sel ... .

This statement is equivalent to f IN sel , if sel was
defined by SELECT-OPTIONS sel FOR f and can be used anywhere
in logical expressions

If the result of this check is negative, the processing in
this event is terminated and the GET events for any
subordinate database tables are not processed either.

This variant of the CHECK statement should be used only if
the logical database for the corresponding table does not
support dynamic selections (see CHECK SELECT-OPTIONS ), or
SELECT-OPTIONS with the addition NO DATABASE SELECTION .
Otherwise, the relevant record is not read from the database
and made available to the program.


CHECK SELECT-OPTIONS.

Effect
Called only after a GET event.
This statement checks all the selections for SELECT-OPTIONS
where the reference field after FOR belongs to the current
table dbtab (specified after GET . However, this applies
only if the logical database for dbtab does not support
dynamic selections . Otherwise, the selections are passed
directly to the logical database (with the exception:
addition " NO DATABASE SELECTION " to SELECT-OPTIONS ).

This variant of the CHECK statement only makes sense if the
logical database does not support dynamic selections for the
corresponding table or SELECT-OPTIONS are defined with the
addition " NO DATABASE SELECTION ".

You can determine from the ABAP/4 Development Workbench
whether dynamic selections are defined and, if so, for which
logical database tables by selecting Development ->
Programming environ. -> Logical databases followed by Extras
-> Dynamic selections .