SQL 2008 Driver not returning SQL_NULL_DATA for null values.

I have this ODBC code that runs fine with SQL 2005 Native Driver connected to
a SQL 2005 database. The same code gives me a different result when I use the
SQL 2008 Native Driver connected to a SQL 2008 database (or for that matter
the problem happens even for SQL 2008 Native Driver connected to SQL 2005
database). So, the problem seems to be with the SQL 2008 Native Driver.

My stripped down version of the ODBC code is as shown below:


long lPtr = 0;
SQLBindCol(myQuery, 1, SQL_C_LONG, &myId, 0, &lPtr);
SQLFetch(myQuery);
if (lPtr == SQL_NULL_DATA)
{
<do something for null data>
}
else
{
<do something for non-null data>
}


For this particular column, the value that is stored in the database is NULL
and that I have verified using the SQL 2008 Management Studio.

When the app is run using SQL 2005 Driver, the variable "lPtr" contains
SQL_NULL_DATA (which is defined as -1 in the SQL.H file)
When the app is run using SQL 2008 Driver, the variable "lPtr" contains 0
(which is the value for SQL_SUCCESS in the SQL.H file)

Now, is this a problem with SQL 2008 Native Driver? Is there some setting or
some parameter that can give me the same result in 2008 as I get in 2005? Or
have I unwittingly stumbled into a SQL 2008 bug?

Thanks.