The %S_FLOAT  directive  produces  an  IEEE  S_floating  literal
  regardless   of  the  current  floating  point  default  of  the
  compilation.  Without the directive,  the  format  of  a  single
  precision  floating  literal  will  be  determined  based on the
  setting of the /FLOAT DCL qualifier or the [FLOAT]  module-level
  attribute.   The  %S_FLOAT directive is not supported on OpenVMS
  VAX systems.  The syntax is:

    %S_FLOAT floating-point-literal