function value = r8_log_10 ( x )

%*****************************************************************************80
%
%% R8_LOG_10 returns the logarithm base 10 of |X|.
%
%  Discussion:
%
%    value = Log10 ( |X| )
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license. 
%
%  Modified:
%
%    12 June 2005
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, real X, the number whose base 2 logarithm is desired.
%    X should not be 0.
%
%    Output, real VALUE, the logarithm base 10 of the absolute
%    value of X.  It should be true that |X| = 10**R8_LOG_10.
%
  if ( x == 0.0 )
    value = -inf;
  else
    value = log10 ( abs ( x ) );
  end

  return
end