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Index Page gfinth_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

       gfinth_c ( GF, interrupt signal handler )

       void gfinth_c ( int sigcode )

#### Abstract

       Respond to the interrupt signal SIGINT: save an indication
       that the signal has been received. This routine restores
       itself as the handler for SIGINT.

#### Required_Reading

       GF

#### Keywords

       GEOMETRY
       SEARCH
       UTILITY

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       sigcode    I   Interrupt signal ID code.

#### Detailed_Input

       sigcode     is a signal code. `sigcode' is expected to be the ANSI C
                   parameter SIGINT, which represents the interrupt signal.

#### Detailed_Output

       None.

#### Parameters

       None.

#### Exceptions

       1)  If `sigcode' is not SIGINT, the error SPICE(INVALIDSIGNAL)
           is signaled (in the SPICE error handling sense).

       2)  If the call to the ANSI C function `signal' made
           by this routine fails, the error SPICE(SIGNALFAILED)
           is signaled (via SPICE error handling).

#### Files

       None.

#### Particulars

       This interrupt handler should be used by routines that
       participate in GF interrupt handling. Such routines should
       call the ANSI C library routine `signal' with the ANSI C
       macro SIGINT and this routine as the input arguments.

       When this routine executes, it re-establishes itself as the
       handler for the interrupt signal SIGINT. Code that uses
       CSPICE interrupt handling must restore the previous
       handler before returning.

       Once this routine is established as the handler for the
       interrupt signal SIGINT, the GF "bail out" test routine
       gfbail_c will return SPICETRUE until the interrupt status
       is cleared via a call to gfclrh_c.

#### 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) Make this routine the GF signal handler, then restore
          the previous handler. This example serves only to
          demonstrate the use of signal; the example code
          performs no useful function.

          Example code begins here.

          /.
             Program gfinth_ex1
          ./
          #include <stdio.h>
          #include <signal.h>
          #include "SpiceUsr.h"

          int main()
          {
             /.
             Prototypes
             ./
             static void      ( * previousHandler )(int);
             static void      ( * handlerPtr      )(int);

             /.
             Make gfinth_c the handler for the SIGINT signal.
             ./
             previousHandler = signal ( SIGINT, gfinth_c );

             if ( previousHandler == SIG_ERR )
             {
                setmsg_c ( "Attempt to establish gfinth_c as the "
                           "handler for the SIGINT signal failed." );
                sigerr_c ( "SPICE(SIGNALFAILED)"                   );
             }
             printf( "gfinth_c has been established as handler "
                     "for SIGNIT signal.\n"                     );

             /.
             Restore the previous handler.
             ./
             handlerPtr = signal ( SIGINT, previousHandler );

             if ( handlerPtr == SIG_ERR )
             {
                setmsg_c ( "Attempt to re-establish the previous "
                           "handler for the SIGINT signal failed." );
                sigerr_c ( "SPICE(SIGNALFAILED)"                   );
             }
             printf( "The previous handler has been re-established "
                     "for SIGNIT signal.\n"                        );

             return ( 0 );
          }

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

          gfinth_c has been established as handler for SIGNIT signal.
          The previous handler has been re-established for SIGNIT signal.

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

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

#### Version

       -CSPICE Version 1.0.1, 05-AUG-2021 (JDR)

           Edited the header to comply with NAIF standard. Extended
           code example to generate outputs and provided example's solution.

       -CSPICE Version 1.0.0, 25-FEB-2009 (NJB)

#### Index_Entries

       GF handle interrupt signal

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

    Fri Dec 31 18:41:07 2021