Message-ID: <38nnq0lmi3v96aqov831lln4mkn3bt11ud@4ax.com>
Date: 2004-11-30T03:44:06Z
From: Duncan Murdoch
Subject: data is getting corrupted
In-Reply-To: <1131.128.193.136.240.1101749262.squirrel@www.forestinformatics.com>
On Mon, 29 Nov 2004 09:27:42 -0800 (PST), "Jeff D. Hamann"
<jeff.hamann@forestinformatics.com> wrote:
>/* this function converts the sample list */
>/* from R into the internal structure */
>struct SAMPLE_RECORD *build_sample_from_sexp( SEXP sample )
>{
[ declarations deleted ]
>
> char temp_sp_code[16];
> struct SAMPLE_RECORD *s_ptr;
> struct SPECIES_RECORD *sp_ptr;
>
> s_ptr = (struct SAMPLE_RECORD *)calloc( 1, sizeof( struct SAMPLE_RECORD
>) );
This allocates a structure, initialized to all zeros.
>/* s_ptr = (struct SAMPLE_RECORD *)Calloc( 1, struct SAMPLE_RECORD ); */
>
> /* *fill in the header info */
> strcpy( s_ptr->forest,
>CHAR(STRING_ELT(get_list_element(sample,"forest"), 0)) ) ;
This copies the string element to the address s_ptr->forest points to,
which is address 0, since you didn't change it from the initial NULL.
I'm surprised you didn't get a bigger error than the one you saw.
[ more deletions ]
>I'm sure there's something I don't understand about the PROTECT/UNPROTECT
>sequence as this seems to work on smaller data.frames
Maybe you were just lucky that the overwriting at address 0 didn't
trash anything in those cases?
Duncan Murdoch