/CHECK

  The /CHECK qualifier causes the compiler to  generate  code  to  test  for
  arithmetic overflow and for array references outside array boundaries when
  the program executes.

  The format of the /CHECK qualifier is as follows:

     /[NO]CHECK[=({[NO]BOUNDS                              },...)]
                  {[NO]OVERFLOW[=([NO]INTEGER,[NO]DECIMAL)]}
                  {ALL                                     }
                  {NONE                                    }

  where:

     BOUNDS         checks array subscripts to ensure that they  are  within
                    array boundaries specified by the program.

     OVERFLOW       enables the detection of arithmetic overflow for integer
                    and packed decimal operations.

  The /CHECK qualifier specifies that both OVERFLOW and BOUNDS checking  are
  performed.    The   /NOCHECK  qualifier  specifies  that  no  checking  is
  performed.  If you specify /CHECK=OVERFLOW, overflow checking  is  enabled
  for  both  integers  and  packed  decimal  numbers.  Similarly, specifying
  /CHECK=NOOVERFLOW disables overflow checking for both types of numbers.

  Specifying /CHECK=NOBOUNDS means that your program  is  smaller  and  runs
  faster.   However, no error is signaled for an array reference outside the
  bounds of an array.   This  means  that  the  program  may  get  a  memory
  management  or access violation error at run time.  Therefore, this option
  should be used only for programs that have been  thoroughly  debugged  and
  whose execution time is critical.

  The default is /CHECK = (BOUNDS, OVERFLOW).