Index Page unload_c
A B C D E F G H I J K L M N O P Q R S T U V W X
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
       void unload_c ( ConstSpiceChar  * file )
#### Abstract
       Unload a SPICE kernel.
#### Required_Reading
       None.
#### Keywords
       KERNEL
#### Brief_I/O
       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       file       I   The name of a kernel to unload.
#### Detailed_Input
       file       is the name of a file to unload.  This file
                  should be one loaded through the interface furnsh_c.
                  If the file is not on the list of loaded kernels
                  no action is taken.

                  Note that if file is a meta-text kernel, all of
                  the files loaded as a result of loading the meta-text
                  kernel will be unloaded.
#### Detailed_Output
       None.
#### Parameters
       None.
#### Exceptions
       1) If the specified kernel is not on the list of loaded kernels
          no action is taken.

       2) If the input file argument pointer is null, the error
          SPICE(NULLPOINTER) will be signaled.

       3) If the input file argument pointer is the empty string, the error
          SPICE(EMPTYSTRING) will be signaled.
#### Files
       None.
#### Particulars
       The call

          unload_c ( file );

       has the effect of "erasing" the last previous call:

          furnsh_c ( file );

       This interface allows you to unload binary and text kernels.
       Moreover, if you used a meta-text kernel to set up your
       working environment, you can unload all of the kernels loaded
       through the meta-kernel by unloading the meta-kernel.

       Unloading Text or Meta-text Kernels.

       Part of the action of unloading text (or meta-text kernels) is
       clearing the kernel pool and re-loading any kernels that were not in
       the specified set of kernels to unload.  Since loading of text
       kernels is not a very fast process, unloading text kernels takes
       considerably longer than unloading binary kernels.  Moreover, since
       the kernel pool is cleared, any kernel pool variables you have set
       from your program by using one of the interfaces pcpool_c, pdpool_c,
       pipool_c, or lmpool_c will be removed from the kernel pool.  For
       this reason, if you plan to use this feature in your program,
       together with one of the routines specified above, you will need to
       take special precautions to make sure kernel pool variables required
       by your program do not inadvertently disappear.
#### Examples
       Suppose that you wish to compare two different sets of kernels
       used to describe the geometry of a mission (for example a predict
       model and a reconstructed model). You can place all of the
       kernels for one model in one meta-text kernel, and the other set
       in a second meta-text kernel.  Let's call these predict.mta and
       actual.mta.

          #include "SpiceUsr.h"
               .
               .
               .
          furnsh_c ( "predct.mta" );

          /.
          Compute quantities of interest and store them
          for comparison with results of reconstructed
          (actual) kernels.

          Now unload the predict model and load the reconstructed
          model.
          ./
          unload_c ( "predct.mta" );
          furnsh_c ( "actual.mta" );

          /.
          Re-compute quantities of interest and compare them
          with the stored quantities.
          ./
#### Restrictions
       See the note regarding the unloading of text and meta-text
       kernels.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman    (JPL)
       W.L. Taber      (JPL)
#### Version
       -CSPICE Version 1.0.0, 01-SEP-1999 (NJB) (WLT)
#### Index_Entries
       Unload a SPICE kernel
#### Link to routine unload_c source file unload_c.c

    Wed Jun  9 13:05:32 2010