Hi,

i discovered that the ODBC api throw an acces violation exception if i close
handles in the wrong order.
is this a bug? i thought that the ODBC API was supposed to return
INVALID_HANDLE if a supplied handle was not valid anymore?

i work with Visulal C++ 7.1, windows XP and SQL server 2000 SP2. i have also
tried this with access.

int main(void)
{
HENV henv;
HDBC hdbc;
HSTMT hstmt;
unsigned char sDSN[] = "northwind";
unsigned char sLogin[] = "sa";
unsigned char sPassword[] = "";

SQLAllocHandle(SQL_HANDLE_ENV,
SQL_NULL_HANDLE,
&henv);

SQLSetEnvAttr(henv,
SQL_ATTR_ODBC_VERSION,
(SQLPOINTER) SQL_OV_ODBC3,
SQL_IS_INTEGER);

//try to allocate a connectionhandle
SQLAllocHandle(SQL_HANDLE_DBC,
henv,
&hdbc);

//try to connect the connectionhandle to a DSN
SQLConnect(hdbc,
sDSN,
strlen((char*)sDSN),
sLogin,
strlen((char*)sLogin),
sPassword,
strlen((char*)sPassword));

//try to create a new stmt handle
SQLAllocHandle(SQL_HANDLE_STMT,
hdbc,
&hstmt);

//close the connection handles
SQLDisconnect(hdbc);
SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
SQLFreeHandle(SQL_HANDLE_ENV, henv);

//free the statement handle.
//now it will crash
SQLFreeHandle(SQL_HANDLE_STMT,hstmt);


return 0;
}

is there a way to make the api not throw exceptions? i know that the handles
should be closed in a different order, but due to specific reasons i cannot
guarantee this. in this case it shoudl return an error.

kind regards,
Bruno.

Sorry, the ODBC documentation explicitly states that the behavior is
undefined in this case.

When you call SQLDisconnect() (and it returns SQL_SUCCESS) it will free your
statement handles for you.

This is by design.

Brannon

"Bruno van Dooren" <microvax@hotmail.com> wrote in message
news:uKzIBxngDHA.2188@TK2MSFTNGP10.phx.gbl...
> Hi,
>
> i discovered that the ODBC api throw an acces violation exception if i
close
> handles in the wrong order.
> is this a bug? i thought that the ODBC API was supposed to return
> INVALID_HANDLE if a supplied handle was not valid anymore?
>
> i work with Visulal C++ 7.1, windows XP and SQL server 2000 SP2. i have
also
> tried this with access.
>
> int main(void)
> {
> HENV henv;
> HDBC hdbc;
> HSTMT hstmt;
> unsigned char sDSN[] = "northwind";
> unsigned char sLogin[] = "sa";
> unsigned char sPassword[] = "";
>
> SQLAllocHandle(SQL_HANDLE_ENV,
> SQL_NULL_HANDLE,
> &henv);
>
> SQLSetEnvAttr(henv,
> SQL_ATTR_ODBC_VERSION,
> (SQLPOINTER) SQL_OV_ODBC3,
> SQL_IS_INTEGER);
>
> //try to allocate a connectionhandle
> SQLAllocHandle(SQL_HANDLE_DBC,
> henv,
> &hdbc);
>
> //try to connect the connectionhandle to a DSN
> SQLConnect(hdbc,
> sDSN,
> strlen((char*)sDSN),
> sLogin,
> strlen((char*)sLogin),
> sPassword,
> strlen((char*)sPassword));
>
> //try to create a new stmt handle
> SQLAllocHandle(SQL_HANDLE_STMT,
> hdbc,
> &hstmt);
>
> //close the connection handles
> SQLDisconnect(hdbc);
> SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
> SQLFreeHandle(SQL_HANDLE_ENV, henv);
>
> //free the statement handle.
> //now it will crash
> SQLFreeHandle(SQL_HANDLE_STMT,hstmt);
>
>
> return 0;
> }
>
> is there a way to make the api not throw exceptions? i know that the
handles
> should be closed in a different order, but due to specific reasons i
cannot
> guarantee this. in this case it shoudl return an error.
>
> kind regards,
> Bruno.
>
>