Image Data Model: _onError

Image Data Model: _onError

Determines actions in case of an error

Syntax
Details
Example

Syntax

CALL SEND (object-id, '_onError'<message><abort>);

Argument Type Description

message
C the string MESSAGE or NOMESSAGE to indicate whether a message should be written when an error occurs

abort
C the string ABORT or NOABORT to indicate whether the program should abort when an error occurs

Argument	Type	Description
message	C	the string MESSAGE or NOMESSAGE to indicate whether a message should be written when an error occurs
abort	C	the string ABORT or NOABORT to indicate whether the program should abort when an error occurs

Details

If you specify either message or abort but not both, the omitted action defaults to its current value, which is the value last specified. For example, if you specify 'MESSAGE NOABORT ' and later you specify 'NOMESSAGE ', the NOABORT remains in effect.

Example

This example shows how to override the default behavior so that the SCL program does not abort. When you do this, make sure to check SYSRC to see if each method completed successfully.

   /* Create the nondisplay object */
image_class =loadclass('sashelp.fsp.imgdat.
                        class');
imgdat_id=instance(image_class);

filename='/usr/local/color/misc/candy.jif';

   /* Set _onError state to not abort so
      we can   */
   /* do our own error recovery if
      _read fails.    */
call send(imgdat_id, '_getOnErrorOptions',
          prevoptions);
call send(imgdat_id, '_onError', 'NOMESSAGE
          NOABORT');

read:
   call send(imgdat_id, '_read', filename);
   sysrc();
   put filename= ;
   if (rc ne 0) then goto error;

      /* Set _onError back to the original
         state so we don't have to */
      /* check return codes every time since
         the code below shouldn't  */
      /* fail and we don't know how to recover
         even if it does (only   */
      /* cases are out-of-memory
                         and file I/O errors).
                                         */
   call send(imgdat_id, '_onError',
             prevoptions);
   call send(imgdat_id, '_quantize', 100);
   call send(imgdat_id, '_rotate', 90);
   call send(imgdat_id, '_negate');
   call send(imgdat_id, '_scale', 100, 100);
   call send(imgdat_id, '_write',
            'output.gif', 'format=gif');
return;

error:
      /* Error handling may reprompt user
         for new image filename to read */
   put 'Replacing JIF in filename with TIFF -
        and retrying the _read';
   filename='/usr/local/color/misc/candy.tif';

      /* Now continue with the _read
         method again. */
   goto read;
return;

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