Real types specify real number values with different degrees of precision.
1 – REAL
The REAL type denotes single-precision real values. The REAL
type is synonymous with the SINGLE type. The largest REAL value
is denoted by MAXREAL. The smallest REAL value is denoted by
MINREAL. EPSREAL denotes the result of subtracting 1.0 from the
smallest REAL value that is greater than 1.0.
Example: 2.4
2.3e2 {exponential notation}
On OpenVMS VAX systems, REAL uses the F_Floating format. On
OpenVMS Alpha systems, REAL can take one of two formats:
F_Floating and IEEE S_Floating. To specify a format, use either
the FLOAT attribute or the /FLOAT command line qualifier.
The default format on OpenVMS VAX and OpenVMS Alpha systems is
F_Floating. The default format on OpenVMS I64 systems is IEEE
S_Floating. On OpenVMS I64 systems, F_Floating is supported by
converting to/from IEEE S_Floating for all floating point
operations.
2 – SINGLE
The SINGLE type denotes single-precision real values. The SINGLE type is synonymous with the REAL type.
3 – F_FLOAT
The F_FLOAT type denotes a F_Floating single-precision real value regardless of the setting of the FLOAT attribute or /FLOAT command line qualifier.
4 – S_FLOAT
The S_FLOAT type denotes a IEEE S_Floating single-precision real value regardless of the setting of the FLOAT attribute or /FLOAT command line qualifier. S_FLOAT is supported on OpenVMS Alpha and OpenVMS I64 systems only.
5 – DOUBLE
The DOUBLE type denotes double-precision real values. To
indicate a double-precision real number, you must include a real
number or an integer, the letter D (or d), and an integer
exponent with its minus sign or optional plus sign. The largest
DOUBLE value is denoted by MAXDOUBLE. The smallest DOUBLE value
is denoted by MINDOUBLE. EPSDOUBLE denotes the result of
subtracting 1.0d0 from the smallest DOUBLE value that is greater
than 1.0d0.
Example: 0D0
4.371528665D-3
On OpenVMS VAX systems, DOUBLE exists in two formats:
D_Floating and G_Floating. On OpenVMS Alpha and OpenVMS I64
systems, DOUBLE exists in three formats: D_Floating,
G_Floating, and IEEE T_Floating.
To specify a format, you can use either the FLOAT attribute or
the /FLOAT command line qualifier. On OpenVMS VAX systems, the
default format is D_Floating. On OpenVMS Alpha systems, the
default format is G_Floating. On OpenVMS I64, the default
format is IEEE T_Floating.
6 – D_FLOAT
The D_FLOAT type denotes a D_Floating double-precision real value regardless of the setting of the FLOAT attribute or /FLOAT command line qualifier.
7 – G_FLOAT
The G_FLOAT type denotes a G_Floating double-precision real value regardless of the setting of the FLOAT attribute or /FLOAT command line qualifier.
8 – T_FLOAT
The T_FLOAT type denotes an IEEE T_Floating double-precision real value regardless of the setting of the FLOAT attribute or /FLOAT command line qualifier. T_FLOAT is supported only on OpenVMS Alpha and OpenVMS I64 Systems.
9 – QUADRUPLE
The QUADRUPLE type denotes quadruple-precision real values. To
indicate a quadruple-precision real number, you must include a
real number or an integer, the letter Q (or q), and an integer
exponent with its minus sign or optional plus sign. The largest
QUADRUPLE value is denoted by MAXQUADRUPLE. The smallest
QUADRUPLE value is denoted by MINQUADRUPLE. EPSQUADRUPLE
denotes the result of subtracting 1.0q0 from the smallest
QUADRUPLE value that is greater than 1.0q0.
Example: 0.11435Q3
3362Q2
0.11825q-4
On OpenVMS VAX systems, QUADRUPLE uses the H_Floating format.
On OpenVMS Alpha and OpenVMS I64 systems, QUADRUPLE uses the
X_Floating format.
10 – H_FLOAT
The H_FLOAT type denotes quadruple-precision real values. The H_FLOAT type is synonymous with the QUADRUPLE type on OpenVMS VAX systems. H_FLOAT is supported only on OpenVMS VAX Systems.
11 – X_FLOAT
The X_FLOAT type denotes quadruple-precision real values. The X_FLOAT type is synonymous with the QUADRUPLE type on OpenVMS Alpha and OpenVMS I64 systems. X_FLOAT is supported only on OpenVMS Alpha and OpenVMS I64 systems.