title: Using scientific notation and underscore kind specifier at the same time for real literals in Fortran
body: <p>Using scientific notation for floating point literals is easy enough in Fortran:</p>
  
  <p><code>1.5d-10</code></p>
  
  <p>would mean a double precision (whatever that means under current Fortran compiler settings) floating point value that approximates <code>1.5*10^-15</code>.</p>
  
  <p>However, the fusion of the exponent notation and the floating point kind specifier is a bit of an issue. How would one declare this floating point literal when one wants it to have a type of <code>C_DOUBLE</code>?</p>
  
  <p>I know that this is a bit of a nitpicking issue, but there can be circumstances when double precision will not be the same as <code>C_DOUBLE</code>.</p>