From: David Hall
Date: August 13 2009 11:20pm
Subject: RE: problem when calling mysqlpp connection object connect function
 after calling disconnect
List-Archive: http://lists.mysql.com/plusplus/8704
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Hi Warren, it still crashes (access violation at the second connect) when y=
our patch is applied (though my original version of simple1.cpp looks a lit=
tle different to yours (from the 3.0.9 release I downloaded.)

(with patch)
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D
mysqlpp::Connection conn(false);
        if (conn.connect(db, server, user, pass)) {
                conn.disconnect();
                conn.connect(db, server, user, pass);
                // Retrieve a subset of the sample stock table set up by re=
setdb
                // and display it.
                mysqlpp::Query query =3D conn.query("select item from stock=
");
                if (mysqlpp::StoreQueryResult res =3D query.store()) {
                        cout << "We have:" << endl;
                        mysqlpp::StoreQueryResult::const_iterator it;
                        for (it =3D res.begin(); it !=3D res.end(); ++it) {
                                mysqlpp::Row row =3D *it;
                                cout << '\t' << row[0] << endl;
                        }
                }
                else {
                        cerr << "Failed to get item list: " << query.error(=
) << endl;
                        return 1;
                }

                //return 0;
        }
        else {
                cerr << "DB connection failed: " << conn.error() << endl;
                return 1;
        }

        conn.disconnect();
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D

My details:

Using MySQL Server 5.1.

I have the following Visual studio versions:

- Visual studio 2003 version 7.1.6030

- Visual studio 2005 version 8.0.50727.762 (SP.050727-7600)

- Visual studio 2008 version 9.0.30729.1 SP

What other information would you like?

Cheers,

Dave

-----Original Message-----
From: Warren Young [mailto:mysqlpp@stripped]
Sent: Friday, 14 August 2009 12:41 AM
To: MySQL++ Mailing List
Subject: Re: problem when calling mysqlpp connection object connect functio=
n after calling disconnect

Wojciech Barski wrote:
> On May 20, 2009, at 5:04 PM, Warren Young wrote:
>
>> Yes, do.  I tried modifying one of the examples to bounce the connection=
 a
> few times in a few different places, and it doesn't affect anything. See =
the
> attached patch.
>
> I seem to be having the same problem. The simple code like this brings th=
e
> access violation exception (on a reconnect try). I've traced it to
> mysql_real_connect line in the dbdriver::connect method.

I still can't reproduce it.  I added these two lines to simple1.cpp, and
it didn't crash:

> Index: examples/simple1.cpp
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- examples/simple1.cpp        (revision 2561)
> +++ examples/simple1.cpp        (working copy)
> @@ -48,9 +48,6 @@
>     mysqlpp::Connection conn(false);
>     if (conn.connect(mysqlpp::examples::db_name, cmdline.server(),
>                 cmdline.user(), cmdline.pass())) {
> -           conn.disconnect();
> -           conn.connect(mysqlpp::examples::db_name, cmdline.server(),
> -                   cmdline.user(), cmdline.pass());
>             // Retrieve a subset of the sample stock table set up by rese=
tdb
>             // and display it.
>             mysqlpp::Query query =3D conn.query("select item from stock")=
;

I tried it on both Linux and Windows.  Please apply the same patch to
your copy of MySQL++.  If it crashes, I'll need some details about the
environment, since it clearly doesn't happen everywhere.  If it doesn't
crash, it's likely that you just didn't follow the README-Visual-C++.txt
instructions carefully enough.

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