DOUBLE PRECISION type specifier

Standard: F77 F90 F95 F2003 F2008 Example program

＜Syntax＞

DOUBLE PRECISION

The blank between DOUBLE and PRECISION is optional.

＜Semantics＞

DOUBLE PRECISION specifies that an entity is of type REAL and double precision kind. It is equivalent to REAL(KIND(0d0)). A double precision entity takes twice as much storage as a single precision entity.

The F90_KIND module contains named constants REAL32, REAL64 and REAL128 which are convenient for specifying Reals with a particular size. The standard intrinsic module ISO_FORTRAN_ENV also contains those constants.

The SELECTED_REAL_KIND intrinsic function can be used to select a real kind based on decimal precision and exponent range requirements. The IEEE_SELECTED_REAL_KIND function in the standard intrinsic module IEEE_ARITHMETIC can also be used to select an ISO/IEC/IEEE 60559 conformant real kind.