qsql_odbc: fix SQLGetStmtAtt usage

Failure to initialize the variable can cause spurious non-zero
values.

http://msdn.microsoft.com/en-us/library/windows/desktop/ms715438(v=vs.85).aspx

"..value can either be a SQLULEN value or a null-terminated character
string. If the value is a SQLULEN value, some drivers may only write the
lower 32-bit or 16-bit of a buffer and leave the higher-order
bit unchanged. Therefore, applications should use a buffer of SQLULEN
and initialize the value to 0 before calling this function. Also, the
BufferLength and StringLengthPtr arguments are not used."

Follow-up to 1509316a37fb2d365230d020d1dfc251c830fd56

Change-Id: I2e92eb845a2590bea0849c52bde8902adff1b419
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
(cherry-picked from qtbase commit af35ee291a1bbbc8627f9a17f7e104898d49b138)

1 files changed, 3 insertions, 5 deletions

diff --git a/src/sql/drivers/odbc/qsql_odbc.cpp b/src/sql/drivers/odbc/qsql_odbc.cpp
index 24357d2..a15a894 100644
--- a/src/sql/drivers/odbc/qsql_odbc.cpp
+++ b/src/sql/drivers/odbc/qsql_odbc.cpp
@@ -967,8 +967,7 @@ bool QODBCResult::reset (const QString& query)
     }
 
     SQLULEN isScrollable = 0;
-    SQLINTEGER bufferLength;
-    r = SQLGetStmtAttr(d->hStmt, SQL_ATTR_CURSOR_SCROLLABLE, &isScrollable, SQL_IS_INTEGER, &bufferLength);
+    r = SQLGetStmtAttr(d->hStmt, SQL_ATTR_CURSOR_SCROLLABLE, &isScrollable, SQL_IS_INTEGER, 0);
     if(r == SQL_SUCCESS || r == SQL_SUCCESS_WITH_INFO)
         QSqlResult::setForwardOnly(isScrollable==SQL_NONSCROLLABLE);
 
@@ -1114,7 +1113,7 @@ bool QODBCResult::fetchLast()
                 "Unable to fetch last"), QSqlError::ConnectionError, d));
         return false;
     }
-    SQLINTEGER currRow;
+    SQLULEN currRow = 0;
     r = SQLGetStmtAttr(d->hStmt,
                         SQL_ROW_NUMBER,
                         &currRow,
@@ -1601,8 +1600,7 @@ bool QODBCResult::exec()
     }
 
     SQLULEN isScrollable = 0;
-    SQLINTEGER bufferLength;
-    r = SQLGetStmtAttr(d->hStmt, SQL_ATTR_CURSOR_SCROLLABLE, &isScrollable, SQL_IS_INTEGER, &bufferLength);
+    r = SQLGetStmtAttr(d->hStmt, SQL_ATTR_CURSOR_SCROLLABLE, &isScrollable, SQL_IS_INTEGER, 0);
     if(r == SQL_SUCCESS || r == SQL_SUCCESS_WITH_INFO)
         QSqlResult::setForwardOnly(isScrollable==SQL_NONSCROLLABLE);