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Index Page chkout_c

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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

       chkout_c ( Module Check Out )

       void chkout_c ( ConstSpiceChar  * module )

#### Abstract

       Inform the CSPICE error handling mechanism of exit from a
       routine.

#### Required_Reading

       ERROR

#### Keywords

       ERROR

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       module     I   The name of the calling routine.

#### Detailed_Input

       module      is the name of the routine calling chkout_c. The
                   named routine is supposed to be `checking out'
                   when it calls chkout_c; that is, the call should be
                   the last executable statement preceding any exit
                   from the routine.

#### Detailed_Output

       None.

#### Parameters

       None.

#### Exceptions

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

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

       The underlying f2c'd CSPICE routine chkout_ does not signal errors;
       rather it writes error messages, so as to avoid recursion. The
       errors detected by chkout_ are:

       3)  If the input module name module does not match the name popped
           from the trace stack, the short error message
           SPICE(NAMESDONOTMATCH) is written to the error output device.

       4)  If the trace stack is empty, the short error message
           SPICE(TRACESTACKEMPTY) is written to the error output device.

#### Files

       None.

#### Particulars

       This routine is part of the CSPICE error handling mechanism.

       Conceptually, the effect of this routine is to `pop' a module
       name from a stack. The routine chkin_c performs the inverse, or
       `push' operation.

       Every routine that participates in the traceback scheme should
       have a call to chkin_c as the second executable statement.
       The first executable statements should be:

          if ( return_c() )
             {
             return;
             }
          else
             {
             chkin_c ( module );
             }

       Here module is the name of the routine in which this code appears.

       The line of code preceding the exit or any return statement
       should be

          chkout_c  ( module );

       All CSPICE routines should call chkin_c and chkout_c, unless they
       are classified as `error free'. Programs linked with CSPICE
       may also use chkin_c and chkout_c.

       Routines that don't call chkin_c and chkout_c won't appear in the
       traceback.

       All routines that call chkin_c must also call chkout_c, or else the
       trace mechanism will become very confused and need alot of therapy.

       It is possible to disable check-ins (and check-outs) by calling
       the trcoff_c. chkin_c and chkout_c will return immediately
       upon entry after trcoff_c has been called. It is not possible to
       re-enable check-ins and check-outs after calling trcoff_c. Routines
       that don't call chkin_c and chkout_c won't appear in the traceback.

#### Examples

       1)  Call chkout_c before a return statement:

              if ( failed() )
                 {
                 chkout_c ( module );
                 return;
                 }

       2)  Call chkout_c before an exit statement:

              chkout_c ( module );
              exit;

       3)  Only ONE call to chkout_c is needed here:

              chkout_c ( module ) ;
              return;

#### Restrictions

       1)  Routines that call this routine must call chkin_c as the second
           executable statement. (The first is a call to return_c() ).

#### Literature_References

       None.

#### Author_and_Institution

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

#### Version

       -CSPICE Version 2.0.2, 02-JUN-2021 (JDR)

           Edited the header to comply with NAIF standard. Added entries
           #1 and #2 to -Exceptions section.

       -CSPICE Version 2.0.1, 08-FEB-1998 (EDW)

           Corrected and clarified header entries.

       -CSPICE Version 2.0.0, 09-JAN-1998 (NJB)

           Input argument filename was changed to type ConstSpiceChar *.

           Re-implemented routine without dynamically allocated, temporary
           strings.

       -CSPICE Version 1.0.0, 25-OCT-1997 (EDW)

#### Index_Entries

       module check out

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

    Fri Dec 31 18:41:02 2021