Index of Functions: A B C D E F G H I J K L M N O P Q R S T U V W X
Index Page furnsh_c

Table of contents

Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries

#### Procedure

       furnsh_c ( Furnish a program with SPICE kernels )

       void furnsh_c ( ConstSpiceChar  * file )

#### Abstract

       Load one or more SPICE kernels into a program.

#### Required_Reading

       None.

#### Keywords

       UTILITY

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       file       I   Name of SPICE kernel file (text or binary).

#### Detailed_Input

       file        is the name of a SPICE kernel file. The file may be
                   either binary or text. If the file is a binary SPICE
                   kernel it will be loaded into the appropriate SPICE
                   subsystem. If `file' is a SPICE text kernel it will be
                   loaded into the kernel pool. If `file' is a SPICE
                   meta-kernel containing initialization instructions
                   (through use of the correct kernel pool variables), the
                   files specified in those variables will be loaded into
                   the appropriate SPICE subsystem.

                   The SPICE text kernel format supports association of
                   names and data values using a "keyword = value" format.
                   The keyword-value pairs thus defined are called "kernel
                   variables."

                   While any information can be placed in a text kernel
                   file, the following string valued kernel variables are
                   recognized by SPICE as meta-kernel keywords:

                      KERNELS_TO_LOAD
                      PATH_SYMBOLS
                      PATH_VALUES

                   Each kernel variable is discussed below.

                      KERNELS_TO_LOAD   is a list of SPICE kernels to be
                                        loaded into a program. If file
                                        names do not fit within the kernel
                                        pool 80 character limit, they may be
                                        continued to subsequent array
                                        elements by placing the continuation
                                        character ('+') at the end of an
                                        element and then placing the
                                        remainder of the file name in the
                                        next array element. (See the
                                        examples below for an illustration
                                        of this technique or consult the
                                        routine stpool_c for further
                                        details.)

                                        Alternatively you may use a
                                        PATH_SYMBOL (see below) to
                                        substitute for some part of a file
                                        name.

                      PATH_SYMBOLS      is a list of strings (without
                                        embedded blanks), which if
                                        encountered following the '$'
                                        character will be replaced with the
                                        corresponding PATH_VALUES string.
                                        Note that PATH_SYMBOLS are
                                        interpreted only in the
                                        KERNELS_TO_LOAD variable. There must
                                        be a one-to-one correspondence
                                        between the values supplied for
                                        PATH_SYMBOLS and PATH_VALUES.

                      PATH_VALUES       is a list of expansions to use when
                                        PATH_SYMBOLS are encountered. See
                                        the -Examples section for an
                                        illustration of use of PATH_SYMBOLS
                                        and PATH_VALUES.

                   These kernel pool variables persist within the kernel
                   pool only until all kernels associated with the
                   variable KERNELS_TO_LOAD have been loaded. Once all
                   specified kernels have been loaded, the variables
                   KERNELS_TO_LOAD, PATH_SYMBOLS and PATH_VALUES are
                   removed from the kernel pool.

#### Detailed_Output

       None. The routine loads various SPICE kernels for use by your
       application.

#### Parameters

       FILSIZ     is the maximum file name length that can be accommodated
                  by the kernel pool. FILSIZ is currently set to 255.

#### Exceptions

       1)  If a problem is encountered while trying to load `file', an
           error is signaled by a routine in the call tree of this
           routine.

       2)  If the input `file' is a meta-kernel and some file in the
           KERNELS_TO_LOAD assignment cannot be found, or if an error
           occurs while trying to load a file specified by this
           assignment, the error is signaled by a routine in the call
           tree of this routine, and this routine will return. Any files
           loaded prior to encountering the failure, including those
           referenced by the KERNELS_TO_LOAD assignment, will remain
           loaded.

       3)  If an attempt to load a text kernel fails while the kernel is
           being parsed, any kernel variable assignments made before
           the failure occurred will be retained in the kernel pool.

       4)  If a PATH_SYMBOLS assignment is specified without a
           corresponding PATH_VALUES assignment, the error
           SPICE(NOPATHVALUE) is signaled by a routine in the call tree
           of this routine.

       5)  If a meta-text kernel is supplied to furnsh_c that contains
           instructions specifying that another meta-text kernel be
           loaded, the error SPICE(RECURSIVELOADING) is signaled by a
           routine in the call tree of this routine.

       6)  If the input file name has non-blank length exceeding FILSIZ
           characters, the error SPICE(FILENAMETOOLONG) is signaled by a
           routine in the call tree of this routine.

       7)  If the input file is a meta-kernel and some file in the
           KERNELS_TO_LOAD assignment has name length exceeding FILSIZ
           characters, the error SPICE(FILENAMETOOLONG) is signaled by a
           routine in the call tree of this routine.

       8)  If the input file is a meta-kernel and some value in the
           PATH_VALUES assignment has length exceeding FILSIZ characters,
           the error SPICE(PATHTOOLONG) is signaled by a routine in the
           call tree of this routine.

       9)  If the input file is a meta-kernel and some file in the
           KERNELS_TO_LOAD assignment has, after symbol substitution,
           combined name and path length exceeding FILSIZ characters, the
           error SPICE(FILENAMETOOLONG) is signaled by a routine in the
           call tree of this routine.

       10) If a kernel pool variable name length exceeds its maximum
           allowed length (see Kernel Required Reading, kernel.req), an
           error is signaled by a routine in the call tree of this
           routine.

       11) If the `file' input string pointer is null, the error
           SPICE(NULLPOINTER) is signaled.

       12) If the `file' input string has zero length, the error
           SPICE(EMPTYSTRING) is signaled.

#### Files

       The input file is examined and loaded into the appropriate
       SPICE subsystem. If the file is a meta-kernel, any kernels
       specified by the KERNELS_TO_LOAD keyword (and if present,
       the PATH_SYMBOLS and PATH_VALUES keywords) are loaded as well.

       In this version of the toolkit the maximum number of kernels that
       can loaded together is limited to 5300. Each time a kernel is loaded
       via furnsh_c, an internal kernel database entry is created for that
       kernel. If a meta-kernel is loaded, a database entry is created for
       the meta-kernel itself and for all files referenced in the
       meta-kernel's KERNELS_TO_LOAD specification. Unloading a kernel or
       meta-kernel deletes database entries created when the file was
       loaded.

       The value above is an upper bound on number of SPICE kernels that
       can be loaded at any time via the furnsh_c interface, but the number
       of kernels that can be loaded may be smaller, since re-loading a
       loaded kernel or meta-kernel results in creation of additional
       database entries.

       Kernels loaded via furnsh_c are subject to constraints imposed by
       lower-level subsystems. The binary kernel systems (SPK, CK, binary
       PCK, EK, and DSK) have their own limits on the maximum number of
       kernels that may be loaded.

       The total number of DAF-based files (this set includes SPKs, CKs,
       and binary PCKs) and DAS-based files (this set includes EKs and
       DSKs) that may be loaded at any time may not exceed 5000. This
       limit applies whether the files are loaded via furnsh_c or
       lower-level loaders such as spklef_c or dafopr_c. File access
       performance normally will degrade slightly as the number of loaded
       kernels increases.

#### Particulars

       This routine provides a uniform interface to the SPICE kernel
       loading systems. It allows you to easily assemble a list of
       SPICE kernels required by your application and to modify that set
       without modifying the source code of programs that make use of
       these kernels.

       Text kernels input to this routine need not have native line
       terminators for the platform. Lower level CSPICE routines can
       read and process non-native text files. This functionality does
       not exist in the Fortran SPICELIB.

       Only text kernel readers include the non-native read capability,
       (ldpool_c and furnsh_c), the generic text file line reader, rdtext_c
       requires native text files.

       Please refer to kernel.req for additional information.

       Kernel pool variable names are restricted to a length of 32
       characters or less.

#### Examples

       The numerical results shown for these examples may differ across
       platforms. The results depend on the SPICE kernels used as
       input, the compiler and supporting libraries, and the machine
       specific arithmetic implementation.

       1) Load the leapseconds kernel naif0007.tls and the planetary
          ephemeris SPK file de405s.bsp.

             furnsh_c ( "naif0007.tls" );
             furnsh_c ( "de405s.bsp"   );

       2) This example illustrates how you could create a meta-kernel
          file for a program that requires several text and binary
          kernels.

          First create a list of the kernels you need in a text file as
          shown below.

             KPL/MK

             File name: furnsh_ex2.tm

             Here are the SPICE kernels required for my application
             program.

             Note that kernels are loaded in the order listed. Thus
             we need to list the highest priority kernel last.

             \begindata

             KERNELS_TO_LOAD = (

                '/home/mydir/kernels/spk/lowest_priority.bsp',
                '/home/mydir/kernels/spk/next_priority.bsp',
                '/home/mydir/kernels/spk/highest_priority.bsp',
                '/home/mydir/kernels/text/leapsecond.ker',
                '/home/mydir/kernels+',
                '/custom+',
                '/kernel_data/constants.ker',
                '/home/mydir/kernels/text/sclk.tsc',
                '/home/mydir/kernels/ck/c-kernel.bc' )

             \begintext

             End of meta-kernel

          Note that the file name

             /home/mydir/kernels/custom/kernel_data/constants.ker

          is continued across several lines in the right hand side of
          the assignment of the kernel variable KERNELS_TO_LOAD.

          Once you've created your list of kernels, call furnsh_c near the
          beginning of your application program to load the meta-kernel
          automatically at program start up.

             furnsh_c ( "furnsh_ex2.tm" );

          This will cause each of the kernels listed in your meta-kernel
          to be loaded.

       3) This example illustrates how you can simplify the previous
          kernel list by using PATH_SYMBOLS.

             KPL/MK

             File name: furnsh_ex3.tm

             Here are the SPICE kernels required for my application
             program.

             We are going to let A substitute for the directory that
             contains SPK files; B substitute for the directory that
             contains C-kernels; and C substitute for the directory that
             contains text kernels. And we'll let D substitute for
             a "custom" directory that contains a special planetary
             constants kernel made just for our mission.

             Note that our PATH_VALUES and the corresponding
             PATH_SYMBOLS must be listed in the same order.

             \begindata

             PATH_VALUES  = ( '/home/mydir/kernels/spk',
                              '/home/mydir/kernels/ck',
                              '/home/mydir/kernels/text',
                              '/home/mydir/kernels/custom/kernel_data' )

             PATH_SYMBOLS = ( 'A',
                              'B',
                              'C',
                              'D'  )

             KERNELS_TO_LOAD = (  '$A/lowest_priority.bsp',
                                  '$A/next_priority.bsp',
                                  '$A/highest_priority.bsp',
                                  '$C/leapsecond.ker',
                                  '$D/constants.ker',
                                  '$C/sclk.tsc',
                                  '$B/c-kernel.bc'         )

             \begintext

             End of meta-kernel

       4) This example illustrates continuation of path values. The
          meta-kernel shown here is a modified version of that from
          example 3.

             KPL/MK

             File name: furnsh_ex4.tm

             Here are the SPICE kernels required for my application
             program.

             We are going to let A substitute for the directory that
             contains SPK files; B substitute for the directory that
             contains C-kernels; and C substitute for the directory that
             contains text kernels. And we'll let D substitute for
             a "custom" directory that contains a special planetary
             constants kernel made just for our mission.

             Note that our PATH_VALUES and the corresponding
             PATH_SYMBOLS must be listed in the same order.

             The values for path symbols A and D are continued over
             multiple lines.

             \begindata

             PATH_VALUES  = ( '/very_long_top_level_path_name/mydir/+',
                              'kernels/spk',
                              '/home/mydir/kernels/ck',
                              '/home/mydir/kernels/text',
                              '/very_long_top_level_path_name+',
                              '/mydir/kernels/custom+',
                              '/kernel_data'                )

             PATH_SYMBOLS = ( 'A',
                              'B',
                              'C',
                              'D'  )

             KERNELS_TO_LOAD = (  '$A/lowest_priority.bsp',
                                  '$A/next_priority.bsp',
                                  '$A/highest_priority.bsp',
                                  '$C/leapsecond.ker',
                                  '$D/constants.ker',
                                  '$C/sclk.tsc',
                                  '$B/c-kernel.bc'         )

             \begintext

             End of meta-kernel

       5) Load a meta-kernel containing three kernels, and separately,
          a text kernel and a binary PCK. Count the number of loaded
          files before and after calling kclear_c.

          Use the meta-kernel shown below to load the required SPICE
          kernels.

             KPL/MK

             File name: furnsh_ex5.tm

             This meta-kernel is intended to support operation of SPICE
             example programs. The kernels shown here should not be
             assumed to contain adequate or correct versions of data
             required by SPICE-based user applications.

             In order for an application to use this meta-kernel, the
             kernels referenced here must be present in the user's
             current working directory.

             The names and contents of the kernels referenced
             by this meta-kernel are as follows:

                File name                     Contents
                ---------                     --------
                de421.bsp                     Planetary ephemeris
                pck00009.tpc                  Planet orientation and
                                              radii
                naif0012.tls                  Leapseconds

             \begindata

                KERNELS_TO_LOAD = ( 'de421.bsp',
                                    'naif0012.tls',
                                    'pck00009.tpc' )

             \begintext

             End of meta-kernel

          Use the PCK kernel below as the binary PCK required for the
          example.

             earth_latest_high_prec.bpc

          Use the FK kernel below as the text kernel required for the
          example.

             RSSD0002.TF

          Example code begins here.

          /.
             Program furnsh_ex5
          ./
          #include <stdio.h>
          #include "SpiceUsr.h"

          int main( )
          {

             /.
             Local variables.
             ./
             SpiceInt             count;

             /.
             Load several kernel files.
             ./
             furnsh_c ( "furnsh_ex5.tm"              );
             furnsh_c ( "RSSD0002.TF"                );
             furnsh_c ( "earth_latest_high_prec.bpc" );

             /.
             Count the number of loaded kernel files.
             ./
             ktotal_c ( "ALL", &count );

             printf( "The total number of kernels after final furnsh_c:  %1d\n",
                                                                         count );

             /.
             Clear the KEEPER system, retrieve the number of loaded
             after the clear.
             ./
             kclear_c ();

             ktotal_c ( "ALL", &count );

             printf( "The total number of kernels after kclear_c      :  %1d\n",
                                                                         count );

             return ( 0 );
          }

          When this program was executed on a Mac/Intel/cc/64-bit
          platform, the output was:

          The total number of kernels after final furnsh_c:  6
          The total number of kernels after kclear_c      :  0

#### Restrictions

       1)  A meta-kernel cannot reference another meta-kernel.

       2)  Failure during an attempt to load a text kernel or a
           meta-kernel can result in a subset of the intended kernel
           variables being set or a subset of the intended files
           being loaded. furnsh_c does not "clean up" so as to undo the
           effects of a failed load operation.

       3)  When a kernel is specified with a relative path, this path
           should be valid at the time when furnsh_c is called and stay
           valid for the rest of the application run. This is required
           because SPICE stores kernel names as provided by the caller
           and uses them to open and close binary kernels as needed
           by the DAF/DAS handle manager subsystem (behind the scenes,
           to allow reading many more binary kernels than available
           logical units), and to automatically reload into the POOL
           the rest of text kernels that should stay loaded when a
           particular text kernel is unloaded.

           Changing the working directory from within an application
           during an application run after calling furnsh_c to load
           kernels specified using relative paths is likely to
           invalidate stored paths and prevent open/close and unload
           operations mentioned above. A simple workaround when this
           is needed is to specify kernels using absolute paths.

#### Literature_References

       None.

#### Author_and_Institution

       C.H. Acton          (JPL)
       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       B.V. Semenov        (JPL)
       W.L. Taber          (JPL)
       E.D. Wright         (JPL)

#### Version

       -CSPICE Version 1.3.5, 29-DEC-2021 (JDR)

           Edited the header to comply with NAIF standard. Added extra
           examples, including a complete code example.

           Added entries #5 to #9 to -Exceptions section, and extended
           entry #10.

           Added FILSIZ description to -Parameters section.

           Added a restriction about specifying kernels using relative
           paths to the -Restrictions section.

       -CSPICE Version 1.3.4, 01-FEB-2017 (BVS)

           Updated discussion in the -Files section to mention the maximum
           number of kernels that can be loaded together.

       -CSPICE Version 1.3.3, 01-JUL-2014 (NJB)

           Updated discussion of partially completed kernel loading.

       -CSPICE Version 1.3.2, 10-FEB-2010 (EDW)

           Corrected header section order. Added mention of the
           restriction on kernel pool variable names to 32 characters
           or less.

       -CSPICE Version 1.0.4, 17-OCT-2005 (EDW)

           Added text to -Particulars section informing of the
           non-native kernel text file reading capability.

       -CSPICE Version 1.0.3, 29-JUL-2003 (NJB) (CHA)

           Numerous updates to improve clarity. Some corrections
           were made.

       -CSPICE Version 1.0.2, 03-JUL-2002 (NJB)

           Documentation fix: corrected second code example. The example
           previously used the kernel variable PATH_NAMES; that name has been
           replaced with the correct name PATH_VALUES.

       -CSPICE Version 1.0.1, 13-APR-2000 (NJB)

           Replaced single quotes with double quotes in a code example.

       -CSPICE Version 1.0.0, 01-SEP-1999 (NJB) (WLT)

#### Index_Entries

       Load SPICE data from a list of items

#### Link to routine furnsh_c source file furnsh_c.c

    Fri Dec 31 18:41:07 2021