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 ekuef_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

       ekuef_c ( EK, unload event file )

       void ekuef_c ( SpiceInt handle )

#### Abstract

       Unload an EK file, making its contents inaccessible to the
       EK reader routines, and clearing space in order to allow other
       EK files to be loaded.

#### Required_Reading

       EK

#### Keywords

       EK
       FILES

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       handle     I   Handle of EK file.

#### Detailed_Input

       handle      is a file handle returned by eklef_c.

#### Detailed_Output

       None.

       See -Particulars for a description of the effect of this routine.

#### Parameters

       None.

#### Exceptions

       1)  Unloading a file that is not loaded has no effect.

#### Files

       This routine unloads a binary EK file from the EK query system.

#### Particulars

       This routine removes information about an EK file from the
       EK system, freeing space to increase the number of other EK
       files that can be loaded. The file is also unloaded from
       the DAS system and closed.

#### Examples

       The numerical results shown for this example 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 two EK files and perform a query on them. During query
          execution, all files will be searched. Unload the previous
          file before each new file is loaded. Unloading files prevents
          them from being searched during query execution.

          Use the EK kernel below to load the Cassini Science Plan
          SPICE E-Kernel File based upon the integrated science
          plan #78.

             S78_CIMSSSUPa.bep

          Use the EK kernel below to load the data based upon the
          integrated science plan #79.

             S79_CIMSSSUPa.bep

          Example code begins here.

          /.
             Program ekuef_ex1
          ./
          #include <stdio.h>
          #include "SpiceUsr.h"

          int main( )
          {

             /.
             Local parameters.
             ./
             #define EKNMLN       18
             #define ERRLEN       1841

             /.
             Local variables
             ./
             SpiceChar            errmsg [ERRLEN];
             SpiceChar          * query;

             SpiceInt             handle;
             SpiceInt             i;
             SpiceInt             nmrows;

             SpiceBoolean         error;

             /.
             Set up the array holding the EK file names.
             ./
             SpiceChar            eknams [2][EKNMLN] = {
                                       "S78_CIMSSSUPa.bep", "S79_CIMSSSUPa.bep" };

             /.
             The EK files contain a table "CASSINI_SP_OBSERVATION",
             that contains columns named:

                NOTES, OBSERVATION_ID, OBSERVATION_TITLE,
                OBS_DESCRIPTION, SCIENCE_OBJECTIVE, SEQUENCE,
                SUBSYSTEM

             Define a set of constraints to perform a query on all
             loaded EK files (the SELECT clause).
             ./
             query = "Select SUBSYSTEM, SCIENCE_OBJECTIVE, OBSERVATION_ID from "
                     "CASSINI_SP_OBSERVATION order by SUBSYSTEM";

             /.
             Load the EK files. This call could be replaced by a call
             to furnsh_c.
             ./
             for ( i = 0; i < 2; i++ )
             {

                eklef_c ( eknams[i], &handle );
                printf( "Loading EK: %s\n", eknams[i] );

                /.
                Query the EK system for data rows matching the
                SELECT constraints.
                ./
                ekfind_c ( query, ERRLEN, &nmrows, &error, errmsg );

                /.
                Check whether an error occurred while processing the
                SELECT clause. If so, output the error message.
                ./
                if ( error )
                {
                   printf( "SELECT clause error: %s\n", errmsg );
                }
                else
                {
                   /.
                   If no error, `nmrows' contains the number of rows
                   matching the constraints specified in the query
                   string.
                   ./
                   printf( "Number of matching rows:  %2d\n", nmrows );
                }

                /.
                Unload the current file. Unloading files prevents
                them from being searched during query execution.
                ./
                ekuef_c ( handle );
                printf( "Unloading EK: %s\n", eknams[i] );
                printf( "\n" );

             }

             return ( 0 );
          }

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

          Loading EK: S78_CIMSSSUPa.bep
          Number of matching rows:   4
          Unloading EK: S78_CIMSSSUPa.bep

          Loading EK: S79_CIMSSSUPa.bep
          Number of matching rows:   5
          Unloading EK: S79_CIMSSSUPa.bep

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)

#### Version

       -CSPICE Version 1.0.1, 10-AUG-2021 (JDR)

           Edited the header to comply with NAIF standard. Added complete
           code example.

       -CSPICE Version 1.0.0, 26-JUL-1998 (NJB)

          Based on SPICELIB Version 1.0.1, 07-JUL-1996 (NJB)

#### Index_Entries

       unload EK file

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

    Fri Dec 31 18:41:06 2021