FreeTDS Development Group

[Sebastien FLAESCH <sf AT 4js.com>]

Hi Frediano,

FYI, we use a single-byte encoding (LANG=POSIX) ...

Here is the code we use, nothing particular, this is the same code we
use for different ODBC drivers...

#define BLOB_BLOCK_SIZE 4096
....
static SQLRETURN getBlobPieces(SqlStatement * st, SQLUSMALLINT fpos,
                               SQLSMALLINT ctype, MyLocator * loc,
                               FILE * out, SQLLEN * plen)
{
    SQLRETURN r = 0;
    char buf[BLOB_BLOCK_SIZE];
    SQLLEN len;
    int i = 0;
    while (1) {
        r = SQLGetData(st->stmtHandle, fpos, ctype,
                       (SQLPOINTER) buf, sizeof(buf), &len);
        if (!SQL_SUCCEEDED(r) || len == 0 || len == SQL_NULL_DATA)
            break;
        if (len > (SQLLEN) sizeof(buf) || len == SQL_NO_TOTAL)
            len = sizeof(buf);
        /* Char data piece get \0, these must be removed! */
        if (ctype == SQL_C_CHAR) {
            if (buf[len - 1] == '\0') {
                len--;
            }
        }
        fwrite(buf, 1, len, out);
    }
    *plen = len;
    return r;
}

Am I missusing SQLGetData()? As you can see, I modify the len after
Does this affect the next call to SQLGetData()?

Anyway, the INITIAL len returned by SQLGetData() is for sure:

   (total-bytes - 1)

When using UTF-8, I get SQL_NO_TOTAL in the first call, but in ASCII,
I get the (total size - 1)...

Seb

On 02/02/2013 08:52 AM, Frediano Ziglio wrote:
> Il giorno 31/gen/2013, alle ore 14:28, Sebastien FLAESCH<sf AT 4js.com>  ha 
> scritto:
>
> > Hi all,
> >
> > Context:
> >
> > $ uname -a
> > SunOS s64x100 5.10 Generic_120012-14 i86pc i386 i86pc
> >
> > FreeTDS versions tested:
> > - freetds-0.92.dev.20120312
> > - freetds-dev.0.92.377
> >
> > When fetching a TEXT from the database (SQL Server 2005), using 
> > SQL_DATA_AT_EXEC,
> > it appears that the SQLGetData() function returns the size of the text data,
> > minus one...
> >
> > I have tested the same FreeTDS version on a Linux 32b, and SQLGetData() 
> > returns
> > the correct length as expected...
>
> Strange! How do you read the length?
>
> > I will continue to investigate, but I wanted to ask if this is a know issue.
> >
> > When connecting to SQL Server 2008 R2, this does not occur, because 
> > SQLGetData()
> > returns SQL_NO_TOTAL and we fetch text pieces in a different way...
>
> This is done to deal with different encodings.
>
> > Thanks
> > Seb
>
> Frediano
>
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