e characters is found,
   the function returns -1.
 </PRE>
<h4><a name="Parameters">Parameters</a></h4>
<PRE>
 
   None. 
 </PRE>
<h4><a name="Exceptions">Exceptions</a></h4>
<PRE>
  
   1) The error SPICE(NULLPOINTER) is signaled if either of 
      the input string pointers is null.

   2) If start is less than 0, <b>cposr_c</b> returns -1. 
 
   3) If start is greater than or equal to the length of the string, 
      the search begins at the last character of the string. 

   4) The function returns -1 i