A REAL(8) or DOUBLE PRECISION constant has more than twice the accuracy of a REAL(4) number, and greater range.
A REAL(8) or DOUBLE PRECISION constant occupies eight bytes of memory. The number of digits that precede the exponent is unlimited, but typically only the leftmost 15 digits are significant.
IEEE T_floating format is used.
The default KIND for DOUBLE PRECISION is affected by compiler option double-size.
Examples
The following examples show valid and invalid REAL(8) or DOUBLE PRECISION constants:
| Valid | |
123456789D+5 |
|
123456789E+5_8 |
|
+2.7843D00 |
|
-.522D-12 |
|
2E200_8 |
|
2.3_8 |
|
3.4E7_8 |
|
| Invalid | Explanation |
-.25D0_2 |
2 is not a valid kind for reals. |
+2.7182812846182 |
No D exponent designator is present; this is a valid single-precision constant. |
123456789.D400 |
Too large for any double-precision format. |
123456789.D-400 |
Too small for any double-precision format. |
See Also