 the full precision of a number to be placed
     in a format that is suitable for porting or archival storage.

     This routine is one of a pair of routines which are used to
     perform conversions between double precision numbers and
     an equivalent base 16 ``scientific notation'' character string
     representation:

        <b>dp2hx_c</b> -- Convert a double precision number into a base 16
                   ``scientific notation'' character string.

        <a href="hx2dp_c.html">hx2dp_c</a> --