/SYNCHRONOUS_EXCEPTIONS

  Controls whether or not the compiler produces additional code  to  emulate
  HP BASIC for OpenVMS VAX exception behavior.

  The format of the /SYNCHRONOUS_EXCEPTIONS qualifier is as follows:

     /[NO]SYNCHRONOUS_EXCEPTIONS

  Normally the compiler may reorder  the  execution  of  certain  arithmetic
  instructions  to  improve  performance.   If  your  program  generates  an
  arithmetic exception, such as  an  overflow  or  divide  by  zero,  it  is
  possible  that  certain statements surrounding the offending statement may
  or may not have executed.

  For example if a source program contains:

                    A = B
                    C = D / E
                    G = F

  and the value of E is zero, the second statement will generate a divide by
  zero  exception.   Because  of instruction reordering, it is possible that
  the assignment of B to A may not take place.  Further, it is possible that
  the assignment of F to G may take place even though the previous statement
  generated an exception.

  The /SYNCHRONOUS_EXCEPTIONS  qualifier  disables  such  reordering.   This
  allows  programs  which rely on arithmetic exceptions occurring at precise
  times to execute as expected.  It only impacts arithmetic  exceptions  and
  variable  stores  in  the  immediate  vicinity of the excepting statement.
  Usually  programs  will   produce   the   correct   result   without   the
  /SYNCHRONOUS_EXCEPTIONS qualifier.

  The /NOSYNCHRONOUS_EXCEPTIONS qualifier allows  the  compiler  to  produce
  more  efficient  code.   However  this  instruction  reordering  can cause
  incompatibilities with VAX BASIC.

  The default is /NOSYNCHRONOUS_EXCEPTIONS.