VMS Help CC, /G_FLOAT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

     /G_FLOAT
     /NOG_FLOAT

  Controls the format of floating-point variables.

  The /[NO]G_FLOAT qualifier is replaced by the /FLOAT qualifier, but
  is retained for compatibility.

  If you specify /NOG_FLOAT, double variables are represented in
  D_floating format.  On OpenVMS VAX systems, if you omit both /FLOAT
  or /G_FLOAT from the command line, double variables are represented
  in D_FLOAT format (unless /MIA is specified, in which case the
  default format is G_FLOAT).

  If you are linking against object-module libraries, a program
  compiled with G_FLOAT format must be linked with the object library
  VAXCRTLG.OLB.