Find the first occurrence in a string of a character NOT belonging 
   to a collection of characters, starting at a specified location, 
   searching forward. 

   SCANNING 

   VARIABLE  I/O  DESCRIPTION 
   --------  ---  -------------------------------------------------- 
   str        I   Any character string. 
   chars      I   A collection of characters. 
   start      I   Position to begin looking for one not in chars. 

   The function returns the index of the first character of str 
   at or following index start that is not in the collection chars. 

   str        is any character string. 

   chars      is a character string containing a collection of
              characters.  Spaces in chars are significant, including
              trailing blanks.  The order in which characters are
              listed is not significant.

   start      is the position in str to begin looking for characters
              not in chars.  start may range from 0 to n-1, where n is
              the number of characters in str.

   The function returns the index of the first character of str (at or
   following index start) that is not one of the characters in the
   string chars.  The returned value normally ranges from 0 to n-1,
   where n is the number of characters in str. If no such character is
   found, the function returns -1.

   None. 

   ncpos_c is case sensitive. 

   An entire family of related CSPICE routines

      cpos_c
      cposr_c
      ncpos_c
      ncposr_c 
      pos_c
      posr_c 

   is described in the Required Reading. 

   Let string == "BOB, JOHN, TED, AND MARTIN    " 
                  012345678901234567890123456789 

   Let chars  == "ABCDEFGHIJKLMNOPQRSTUVWXYZ" 


   Normal (Sequential) Searching: 
   ------------------------------ 

      ncpos_c( string, chars,  0 ) ==  3
      ncpos_c( string, chars,  4 ) ==  4 
      ncpos_c( string, chars,  5 ) ==  9 
      ncpos_c( string, chars, 10 ) == 10 
      ncpos_c( string, chars, 11 ) == 14 
      ncpos_c( string, chars, 15 ) == 15 
      ncpos_c( string, chars, 16 ) == 19 
      ncpos_c( string, chars, 20 ) == 26 
      ncpos_c( string, chars, 27 ) == 27 
      ncpos_c( string, chars, 28 ) == 28 
      ncpos_c( string, chars, 29 ) == 29 

   start out of bounds: 
   -------------------- 

      ncpos_c( string, chars, -12 ) ==  3 
      ncpos_c( string, chars,  -1 ) ==  3 
      ncpos_c( string, chars,  30 ) == -1 
      ncpos_c( string, chars, 122 ) == -1

   None. 

   1) The error SPICE(NULLPOINTER) is signaled if either of 
      the input string pointers is null.

   2) If start is less than 0, the search begins at the first 
      character of the string. 

   3) If start is greater than or equal to the length of the string, 
      ncpos_c returns -1. 

   4) The function returns -1 if either of the input strings is empty.

   None. 

   N.J. Bachman    (JPL) 
   W.L. Taber      (JPL) 

   None. 

   -CSPICE Version 1.0.0, 14-AUG-2002 (NJB) (WLT)

   forward search for position of unlisted character