specifies that FTN95 should treat all single precision (KIND=1) variables and constants as double precision (KIND=2). Correspondingly, all COMPLEX variables are treated as COMPLEX(KIND=2). It is not necessary to use the generic forms of the intrinsic functions when using /DREAL. If /DREAL is used, the compiler becomes aware of the allowable extensions. (Note that FTN95 does not act as a standard-conforming compiler when /DREAL is used.)
/DREAL can make it very easy to compile and execute a single precision program that has produced valid results on a machine with a more accurate single precision floating point representation, which would otherwise not work satisfactorily without a major conversion.