..
  Copyright 1988-2022 Free Software Foundation, Inc.
  This is part of the GCC manual.
  For copying conditions, see the copyright.rst file.

.. _log10:

.. index:: LOG10

.. index:: ALOG10

.. index:: DLOG10

.. index:: exponential function, inverse

.. index:: logarithm function with base 10

.. index:: base 10 logarithm function

LOG10 --- Base 10 logarithm function
************************************

.. function:: LOG10(X)

  ``LOG10(X)`` computes the base 10 logarithm of :samp:`{X}`.

  :param X:
    The type shall be ``REAL``.

  :return:
    The return value is of type ``REAL`` or ``COMPLEX``.
    The kind type parameter is the same as :samp:`{X}`.

  Standard:
    Fortran 77 and later

  Class:
    Elemental function

  Syntax:
    .. code-block:: fortran

      RESULT = LOG10(X)

  Example:
    .. code-block:: fortran

      program test_log10
        real(8) :: x = 10.0_8
        x = log10(x)
      end program test_log10

  Specific names:
    .. list-table::
       :header-rows: 1

       * - Name
         - Argument
         - Return type
         - Standard

       * - ``ALOG10(X)``
         - ``REAL(4) X``
         - ``REAL(4)``
         - Fortran 77 and later
       * - ``DLOG10(X)``
         - ``REAL(8) X``
         - ``REAL(8)``
         - Fortran 77 and later