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Re: 961113: NETCDF bug (fwd) - still there

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  • Subject: Re: 961113: NETCDF bug (fwd) - still there
  • Date: Thu, 14 Nov 1996 09:23:32 -0700
>To: address@hidden
>From: Harry Edmon <address@hidden>
>Subject: NETCDF bug (fwd) - still there
>Organization: Dept of Atmospheric Sciences, University of Washington
>Keywords: 199611132130.AA29004

Hi Harry,

> This bug still exists in the current version of netcdf (2.4.3) running
> under Digital Unix 4.0A.  The problem is that the file has a global
> attribute with zero length.  This causes malloc of zero bytes in ncdump
> which returns nil, which is interpretted by ncdump as out of memory.
> 
> Forwarded message:
> > From harry Wed Feb 14 14:11:22 1996
> > Subject: NETCDF bug

Actually, the message you forwarded from Feb 14 demonstrated a bug with
zero-length *variable* attributes.  This was fixed in netCDF 2.4, but
not for zero-length *global* attributes.  Sorry about that, these should
have been handled by common code, and will be in netCDF-3.  I've
appended a patch for netCDF 2.4.3.

--Russ

*** /home/russ/upc/netcdf/netcdf-2.4.3/src/ncdump/ncdump.c      Fri Jun  7 
08:42:07 1996
--- ncdump.c    Thu Nov 14 09:16:33 1996
***************
*** 1,7 ****
  /*********************************************************************
   *   Copyright 1993, University Corporation for Atmospheric Research
   *   See netcdf/README file for copying and redistribution conditions.
!  *   $Header: /upc/share/CVS/netcdf/ncdump/ncdump.c,v 1.50 1996/05/14 
16:45:14 russ Exp $
   *********************************************************************/
  
  #include <stdio.h>
--- 1,7 ----
  /*********************************************************************
   *   Copyright 1993, University Corporation for Atmospheric Research
   *   See netcdf/README file for copying and redistribution conditions.
!  *   $Header: /upc/share/CVS/netcdf/ncdump/ncdump.c,v 1.51 1996/11/14 
16:16:33 russ Exp $
   *********************************************************************/
  
  #include <stdio.h>
***************
*** 372,387 ****
        Printf ("\t\t:%s = ", att.name);
        
        (void) ncattinq(ncid, NC_GLOBAL, att.name, &att.type, &att.len);
!       att.val = (void *) malloc((unsigned) (att.len*nctypelen(att.type)));
!       if (!att.val) {
!           error("Out of memory!");
!           (void) ncclose(ncid);
!           if (vlist)
!               free(vlist);
!           return;
        }
-       (void) ncattget(ncid, NC_GLOBAL, att.name, att.val);
- 
        pr_att_vals(att.type, att.len, att.val);
        Printf (" ;\n");
        free ((char *) att.val);
--- 372,393 ----
        Printf ("\t\t:%s = ", att.name);
        
        (void) ncattinq(ncid, NC_GLOBAL, att.name, &att.type, &att.len);
!       if (att.len == 0) {     /* show 0-length attributes as empty strings */
!           att.type = NC_CHAR;
!           att.val = (char *) malloc(1);
!           att.len = 1;
!           *(char *)att.val = '\0';
!       } else {
!           att.val = (void *) malloc((unsigned) (att.len*nctypelen(att.type)));
!           if (!att.val) {
!               error("Out of memory!");
!               (void) ncclose(ncid);
!               if (vlist)
!                   free(vlist);
!               return;
!           }
!           (void) ncattget(ncid, NC_GLOBAL, att.name, att.val);
        }
        pr_att_vals(att.type, att.len, att.val);
        Printf (" ;\n");
        free ((char *) att.val);