Re: writing fits images from isis

On Wed, May 26, 2004 at 12:09 -0400, Frank Primini wrote:
> I'm trying to write a fits image from within ISIS, using the fits routines in varmm.
> 
> The following does not work:
> 
> calf-13: isis
> 
> Welcome to ISIS Version 1.1.6
> Copyright (C) 1998, 2003 Massachusetts Institute of Technology
> 
> isis> import("varmm");
> isis> variable foo=readimage("ngc4038.fits");
> isis> writefits("foo.fits",foo,"zero",NULL,1);
> Application error: Type 109 not registered
> 
> **** isis:  Fatal Error:  Please report this bug to houck_at_email.domain.hidden> ****        If you got a 'core' file, please keep it to help with debugging.
> 
> Aborted
> calf-14:
> 
> However, from slsh it does. Can anyone tell me what I'm doing wrong?
> 


Hi Frank,

I believe this is a bug in varmm.  The bug is triggered when
varmm is imported into an application which has already defined
Fits_File_Type.  The effect of the bug is to cause varmm to
read from memory which has not been initialized. Depending on
the contents which are read, the appliation may or may not
crash with a core dump.

It is possible to exploit this bug to generate the same
behavior in slsh:

  > cat crash.sl 
  require ("fits");
  import("varmm");
  variable foo = readimage("x.fits");
  writefits("foo.fits",foo,"zero",NULL,1);
  > slsh < crash.sl
  Application error: Type 109 not registered
  >

This script first loads the fits module to make sure that
Fits_File_Type is defined by the application, then the rest of
the script is the same as the example you gave.  In this case
no core dump was produced, but the "Application error" is the
same.

Sorry for the slow reply - I was out of town for a few days.

Thanks,
-John

-- 
John C. Houck         MIT Center for Space Research
tel: 617-253-3849           77 Massachusetts Avenue
fax: 617-253-8084          Cambridge, MA 02139-4307
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