[freetds] what size indicator

ZIGLIO, Frediano, VF-IT Frediano.Ziglio at vodafone.com
Fri Jun 4 08:50:39 EDT 2004


> 
> typedef struct tds_column
> {
> ...
> 	TDS_SMALLINT *column_nullbind;
> ...
> } TDSCOLUMN;
> 
> blk_bind(CS_BLKDESC * blkdesc, CS_INT item, CS_DATAFMT * 
> datafmt, CS_VOID
> * buffer, CS_INT * datalen, CS_SMALLINT * indicator)
> 
> dbnullbind(DBPROCESS * dbproc, int column, DBINT * indicator)
>                                            ^^^^^
> 
> Bill, 
> 
> As you can see, db-lib defines the nullbind indicator as an 
> address of a
> 32-bit pointer, and ct-lib a 16-bit pointer.  Compiling db-lib with a
> modern compiler will yield complaints.  (I take it yours is 
> pre-modern, or
> you have the volume turned down. ;-) )
> 
> How best to resolve this?  I think we need to define it as 32-bits in
> TDSCOLUMN, and cast the ct-lib down to 16.  I don't think 
> anything else is
> safe.  But I thought I'd check.  
> 
> Interestingly, the bugger used to be (as you know) CHAR*.  I 
> wonder why I
> never saw this warning before.
> 
> Regards, 
> 

Last Bill patch change the pointer from TDS_CHAR* to TDS_INT *.

>From include/tds.h

...
        /* related to binding or info stored by client libraries */
        /* FIXME find a best place to store these data, some are unused
*/
        TDS_SMALLINT column_bindtype;
        TDS_SMALLINT column_bindfmt;
        TDS_UINT column_bindlen;
        TDS_SMALLINT *column_nullbind;
        TDS_CHAR *column_varaddr;
        TDS_INT *column_lenbind;
        TDS_INT column_textpos;
        TDS_INT column_text_sqlgetdatapos;
        BCPCOLDATA *bcp_column_data;
...

These fields are only used by client libraries (not libTDS) so every
library should use as they like. Perhaps an union like

	union {
		struct {
			...
		} db;
		struct {
			...
		} ct;
	} lib;
would be better ??

>From this page
http://sybooks.sybase.com/onlinebooks/group-cn/cng1251e/comlib/@Generic_
_BookTextView/12663 blk_init declaration seems

CS_RETCODE blk_bind(blkdesc, colnum, datafmt, buffer,
                datalen, indicator)
 
 CS_BLKDESC     *blkdesc;
 CS_INT                colnum;
 CS_DATAFMT     *datafmt;
 CS_VOID             *buffer;
 CS_INT                *datalen;
 CS_SMALLINT     *indicator;

however from the same page, below:

indicator

A pointer to a CS_INT variable, or for array binding, an array of
CS_INT. At row-transfer time, blk_rowxfer_mult or blk_rowxfer read the
indicator's contents to determine certain conditions about the bulk-copy
data. See the "List of Bulk-Library routines" section for details.

??? a pointer to CS_SMALLINT or to CS_INT ???

freddy77



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