Syntax:
The /real_size or /4R8 option controls the size (in bits) of REAL and COMPLEX declarations, constants, functions, and intrinsics. In the visual development environment, specify the Default Real Kind in the Fortran Data Compiler Option Category. The /real_size options are:
Defines REAL declarations, constants, functions, and intrinsics as REAL(KIND=4) (SINGLE PRECISION). It also defines COMPLEX declarations, constants, functions, and intrinsics as COMPLEX(KIND=4) (COMPLEX). This is the default.
Defines REAL declarations, constants, functions, and intrinsics as REAL(KIND=8) (DOUBLE PRECISION). It also defines COMPLEX declarations, constants, functions, and intrinsics as COMPLEX(KIND=8).
Specifying /real_size:64 causes intrinsic functions to produce a REAL(KIND=8) or COMPLEX(KIND=8) result instead of a REAL(KIND=4) or COMPLEX(KIND=4) result, unless the argument is explicitly typed as REAL(KIND=4) or COMPLEX(KIND=4), including CMPLX, FLOAT, REAL, SNGL, and AIMAG. For instance, references to the CMPLX intrinsic produce DCMPLX results (COMPLEX(KIND=8)), unless the argument to CMPLX is explicitly typed as REAL(KIND=4), REAL*4, COMPLEX(KIND=4), or COMPLEX*8. In this case the resulting data type is COMPLEX(KIND=4).