Retrieve the nth string from the kernel pool variable, where the
   string may be continued across several components of the kernel pool
   variable.

    None. 

   VARIABLE  I/O  DESCRIPTION 
   --------  ---  -------------------------------------------------- 
   item       I   Name of the kernel pool variable.
   nth        I   Index of the full string to retrieve.
   contin     I   Character sequence used to indicate continuation.
   lenout     I   Available space in output string.
   string     O   A full string concatenated across continuations. 
   size       O   The number of characters in the full string value. 
   found      O   Flag indicating success or failure of request. 

   item       is the name of a kernel pool variable for which 
              the caller wants to retrieve a full (potentially 
              continued) string.

   nth        is the number of the string to retrieve from the kernel
              pool.  The range of `nth' is 0 to one less than the
              number of full strings that are present.

   contin     is a sequence of characters which (if they appear as the
              last non-blank sequence of characters in a component of a
              value of a kernel pool variable) act as a continuation
              marker:  the marker indicates that the string associated
              with the component containing it is continued into the
              next literal component of the kernel pool variable.

              If contin is blank, all of the components of `item'
              will be retrieved as a single string. 

   lenout     is the available space in the output string, counting
              room for the terminating null.  Up to lenout-1 "data" 
              characters will be assigned to the output string.

   string     is the nth full string associated with the kernel 
              pool variable specified by item. 

              Note that if `string' is not sufficiently long to hold
              the fully continued string, the value will be truncated.
              You can determine if `string' has been truncated by
              examining the variable `size'.  `string' will always be
              null-terminated, even if truncation of the data occurs.

   size       is the index of last non-blank character of the continued
              string as it is represented in the kernel pool.  This is
              the actual number of characters needed to hold the
              requested string.  If `string' contains a truncated
              portion of the full string, strlen(string) will be less
              than `size'.

              If the value of `string' should be a blank, then 
              SIZE will be set to 1. 

   found      is a logical variable indicating success of the 
              request to retrieve the nth string associated 
              with item.  If an nth string exists, `found' will be 
              set to SPICETRUE; otherwise `found' will be set to
              SPICEFALSE.

   None. 

   The SPICE Kernel Pool provides a very convenient interface for
   supplying both numeric and textual data to user application
   programs.  However, any particular component of a character valued
   component of a kernel pool variable is limited to 80 or fewer
   characters in length.

   This routine allows you to overcome this limitation by "continuing"
   a character component of a kernel pool variable. To do this you need
   to select a continuation sequence of characters and then insert this
   sequence as the last non-blank set of characters that make up the
   portion of the component that should be continued.

   For example, you may decide to use the sequence "//" to indicate
   that a string should be continued to the next component of a kernel
   pool variable.   Then set up the kernel pool variable as shown below:

      LONG_STRINGS = ( 'This is part of the first component //' 
                       'that needs more than one line when //' 
                       'inserting it into the kernel pool.' 
                       'This is the second string that is split //' 
                       'up as several components of a kernel pool //' 
                       'variable.' ) 

   When loaded into the kernel pool, the variable LONG_STRINGS 
   will have six literal components: 

      component[0] == "This is part of the first component //" 
      component[1] == "that needs more than one line when //" 
      component[2] == "inserting it into the kernel pool." 
      component[3] == "This is the second string that is split //" 
      component[4] == "up as several components of a kernel pool //" 
      component[5] == "variable." 

   These are the components that would be retrieved by the call 

      gcpool_c ( "LONG_STRINGS", 1, 6, 81, &n, component, &found ); 

   However, using the routine stpool_c you can view the variable 
   LONG_STRINGS as having two long components. 

      string [0] == "This is part of the first component that " 
                    "needs more than one line when inserting " 
                    "it into the kernel pool. " 

      string [1] == "This is the second string that is split " 
                    "up as several components of a kernel pool " 
                    "variable. " 


   These string components would be retrieved by the following two 
   calls.  We will use 81 as the length of the elements of the string
   array.

      stpool_c( "LONG_STRINGS", 0, "//", 81, string[0], &size, &found ); 
      stpool_c( "LONG_STRINGS", 1, "//", 81, string[1], &size, &found ); 

   Example 1.  Retrieving file names. 

      Suppose a you have used the kernel pool as a mechanism for
      specifying SPK files to load at startup but that the full names
      of the files are too long to be contained in a single text line
      of a kernel pool assignment.

      By selecting an appropriate continuation character ("*" for
      example)  you can insert the full names of the SPK files into the
      kernel pool and then retrieve them using this routine.

      First set up the kernel pool specification of the strings 
      as shown here: 

            SPK_FILES = ( 'this_is_the_full_path_specification_*' 
                          'of_a_file_with_a_long_name' 
                          'this_is_the_full_path_specification_*' 
                          'of_a_second_file_with_a_very_long_*' 
                          'name' ) 

      Now to retrieve and load the SPK_FILES one at a time, 
      exercise the following loop. 

         #include <stdio.h>
         #include <string.h>
         #include "SpiceUsr.h"
             .
             .
             .
         #define FILSIZ          255

         SpiceBoolean            found;

         SpiceChar               file [ FILSIZ ];

         SpiceInt                handle;
         SpiceInt                i;
         SpiceInt                size;


         i = 0; 

         stpool_c ( "SPK_FILES", i, "*", FILSIZ, file, &size, &found );

         while (  found  &&  ( strlen(file) == size )  )
         {
            spklef_c ( file, &handle );

            i++;

            stpool_c ( "SPK_FILES",  i,      "*",    FILSIZ, 
                       file,         &size,  &found          );
         }

         if (  found  &&  ( strlen(file) != size )  )
         {
            printf ( "The %d th file name was too long\n", i );
         }



   Example 2. Retrieving all components as a string. 


   Occasionally, it may be useful to retrieve the entire 
   contents of a kernel pool variable as a single string.  To 
   do this you can use the blank character as the 
   continuation character.  For example if you place the 
   following assignment in a text kernel 

       COMMENT = (  'This is a long note ' 
                    ' about the intended ' 
                    ' use of this text kernel that ' 
                    ' can be retrieved at run time.' ) 

   you can retrieve COMMENT as single string via the call below. Here
   LENOUT is the declared length of commnt.

      stpool_c ( "COMMENT", 1, " ", commnt, LENOUT, &size, &found ); 

   The result will be that commnt will have the following value. 

      commnt == "This is a long note about the intended use of " 
                "this text kernel that can be retrieved at run " 
                "time. " 

   Note that the leading blanks of each component of COMMENT are 
   significant; trailing blanks are not significant. 

   If COMMENT had been set as 

       COMMENT = (  'This is a long note ' 
                    'about the intended ' 
                    'use of this text kernel that ' 
                    'can be retrieved at run time.' ) 

   Then the call to stpool_c above would have resulted in several 
   words being run together as shown below. 


      commnt == "This is a long noteabout the intendeduse of " 
                "this text kernel thatcan be retrieved at run " 
                "time. " 


   resulted in several words being run together as shown above. 

   None. 

   1) If the variable specified by item is not present in the kernel
      pool or is present but is not character valued, string will be
      returned as a null string, size will be returned with the value 0 
      and found will be set to SPICEFALSE.

   2) If the variable specified has a blank string associated 
      with its nth full string, string will be blank, size 
      will be 1 and found will be set to SPICETRUE.

   3) If string is not long enough to hold all of the characters 
      associated with the nth string, it will be truncated on the 
      right.  string will still be null terminated.

   4) If the continuation character is a blank, every component 
      of the variable specified by item will be inserted into 
      the output string. 

   5) If the continuation character is blank, then a blank component 
      of a variable is treated as a component with no letters. 
      For example: 

         STRINGS = ( 'This is a variable' 
                     'with a blank' 
                     ' ' 
                     'component.' ) 

      Is equivalent to 


         STRINGS = ( 'This is a variable' 
                     'with a blank' 
                     'component.' ) 

      from the point of view of stpool_c if contin is set to the 
      blank character. 

   6) If either the input or output string pointers are null, the error 
      SPICE(NULLPOINTER) will be signaled.

   7) If any input strings have length zero, the error 
      SPICE(EMPTYSTRING) will be signaled.

   8) The caller must pass a value indicating the length of the output
      string.  If this value is not at least 2, the error
      SPICE(STRINGTOOSHORT) will be signaled.

   None. 

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

   None. 

   -CSPICE Version 1.2.0, 06-SEP-2004 (NJB)

      Bug fix: added CHKOSTR call to check output string pointer
      and length.  Made some minor header updates.

   -CSPICE Version 1.1.0, 06-MAY-2003 (NJB)

      Bug fix:  removed extra #include statement referencing
      SpiceZfc.h.

   -CSPICE Version 1.0.1, 10-JUN-2001 (NJB)

      Header was corrected:  kernel variable assignments were shown
      using double quotes; these have been changed to single quotes.

      Various instances of the '=' operator were replaced with the
      '==' operator in comments where the intent was to indicate
      equality of two items.

   -CSPICE Version 1.0.0, 10-JUN-1999 (NJB) (WLT)

   Retrieve a continued string value from the kernel pool