gcc/fortran/doc/gfortran/intrinsic-procedures/selectedintkind.rst

   1 ..
   2   Copyright 1988-2022 Free Software Foundation, Inc.
   3   This is part of the GCC manual.
   4   For copying conditions, see the copyright.rst file.
   5
   6 .. index:: SELECTED_INT_KIND, integer kind, kind, integer
   7
   8 .. _selected_int_kind:
   9
  10 SELECTED_INT_KIND --- Choose integer kind
  11 *****************************************
  12
  13 .. function:: SELECTED_INT_KIND(R)
  14
  15   ``SELECTED_INT_KIND(R)`` return the kind value of the smallest integer
  16   type that can represent all values ranging from -10^R (exclusive)
  17   to 10^R (exclusive). If there is no integer kind that accommodates
  18   this range, ``SELECTED_INT_KIND`` returns -1.
  19
  20   :param R:
  21     Shall be a scalar and of type ``INTEGER``.
  22
  23   Standard:
  24     Fortran 90 and later
  25
  26   Class:
  27     Transformational function
  28
  29   Syntax:
  30     .. code-block:: fortran
  31
  32       RESULT = SELECTED_INT_KIND(R)
  33
  34   Example:
  35     .. code-block:: fortran
  36
  37       program large_integers
  38         integer,parameter :: k5 = selected_int_kind(5)
  39         integer,parameter :: k15 = selected_int_kind(15)
  40         integer(kind=k5) :: i5
  41         integer(kind=k15) :: i15
  42
  43         print *, huge(i5), huge(i15)
  44
  45         ! The following inequalities are always true
  46         print *, huge(i5) >= 10_k5**5-1
  47         print *, huge(i15) >= 10_k15**15-1
  48       end program large_integers