5.1 KIND Type Parameters

The KIND type parameters supported by GNU Fortran for the primitive data types are:

INTEGER

1, 2, 4, 8*, 16*, default: 4 (1)

LOGICAL

1, 2, 4, 8*, 16*, default: 4 (1)

REAL

4, 8, 10*, 16*, default: 4 (2)

COMPLEX

4, 8, 10*, 16*, default: 4 (2)

CHARACTER

1, 4, default: 1

* = not available on all systems
(1) Unless -fdefault-integer-8 is used
(2) Unless -fdefault-real-8 is used

The KIND value matches the storage size in bytes, except for COMPLEX where the storage size is twice as much (or both real and imaginary part are a real value of the given size). It is recommended to use the SELECTED_CHAR_KIND, SELECTED_INT_KIND and SELECTED_REAL_KIND intrinsics or the INT8, INT16, INT32, INT64, REAL32, REAL64, and REAL128 parameters of the ISO_FORTRAN_ENV module instead of the concrete values. The available kind parameters can be found in the constant arrays CHARACTER_KINDS, INTEGER_KINDS, LOGICAL_KINDS and REAL_KINDS in the ISO_FORTRAN_ENV module (see ISO_FORTRAN_ENV).