If in the same document more than 1 call to odbc_connect are performed,
the second or subsequent calls fail witout an error. The returned id is empty. Connections with different user/password to the same source will succeed.
Tested with adabas d database.

Sample code:

$cid = odbc_connect($server,$user,$pass);
echo "ID1=$cid<BR>";
odbc_close($cid);
$cid = odbc_connect($server,$user,$pass);
echo "ID2=$cid<BR>";
odbc_close($cid);