Qstring conversion UTF8

[harleyskater]

QString Qstr1 = ui.usrLineEdit->text();
QString Qstr2 = ui.pwdLineEdit->text();

char *acsUserName = new char[ Qstr1.length() + 1 ]; // + 1 for zero in the end of string
memcpy( acsUserName, Qstr1.toUtf8().constData(),Qstr1.length() + 1 );
char *acsPassword = new char[ Qstr2.length() + 1 ]; // + 1 for zero in the end of string
memcpy( acsPassword, Qstr2.toUtf8().constData(), Qstr2.length() + 1 );

this compiles but my code still isn't working properly. I'm kind of annoyed because I can not create breakpoints in Visual Studios when using QT. It makes it difficult to problem solve but I know its not executing properly because I am checking the number of rows returned from my query is not greater than zero

if (res.num_rows() > 0)
	{
		qApp->exit(0);
		//goodlogin 
	}
	else
	{
		//badlogin
	}

if (res.num_rows() > 0)
	{
		qApp->exit(0);
		//goodlogin 
	}
	else
	{
		//badlogin
	}

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[squidge]

If you can't do breakpoints in Visual Studios when using QT then your VS installation is broken.

Secondly, since your converting to UTF8, the number of bytes to copy might be more than the number of characters in the string, so you can't use Qstr1.length() (one character could be upto 4 bytes in the output). This is why a QString is an array of QChar and not Char.

try and use qDebug for your string

[harleyskater]

I will reinstall my VS 2005, the breakpoints work great in non-qt apps, I also opened up a thread in the newbie qt to get some help with this issue.

is QT compatible with 2008 express?

[ChrisW67]

Since you are using Qt and making a single atomic use of the UTF8 strings I think that:

char *acsUserName = new char[ Qstr1.length() + 1 ]; // + 1 for zero in the end of string
memcpy( acsUserName, Qstr1.toUtf8().constData() );
char *acsPassword = new char[ Qstr2.length() + 1 ]; // + 1 for zero in the end of string
memcpy( acsPassword, Qstr2.toUtf8().constData() );
foo( acsUserName, acsPassword );
delete []acsUserName;
delete []acsPassword;

char *acsUserName = new char[ Qstr1.length() + 1 ]; // + 1 for zero in the end of string
memcpy( acsUserName, Qstr1.toUtf8().constData() );
char *acsPassword = new char[ Qstr2.length() + 1 ]; // + 1 for zero in the end of string
memcpy( acsPassword, Qstr2.toUtf8().constData() );
foo( acsUserName, acsPassword );
delete []acsUserName;
delete []acsPassword;

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is probably more elegantly put without intervening temporary variables and manual memory shuffle:

foo( Qstr1.toUtf8().constData(), Qstr2.toUtf8().constData() );

foo( Qstr1.toUtf8().constData(), Qstr2.toUtf8().constData() );

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The temporary QByteArray object scope extends to the end of the foo() call. If you need to make multiple uses of the UTF8 string:

QByteArray username = QStr1.toUtf8();
QByteArray password = QStr2.toUtf8();
foo( username.constData(), password.constData() );
bar( username.constData() );

QByteArray username = QStr1.toUtf8();
QByteArray password = QStr2.toUtf8();
foo( username.constData(), password.constData() );
bar( username.constData() );

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and let QByteArray worry about NUL termination, memory allocation, and necessary size.

[squidge]

is QT compatible with 2008 express?

Qt is, but Express editions of VS have no support for plugins, so you will have to do everything yourself.

[Lesiok]

Because I'm lazy all SQL queries I have making like this :

QSqlQuery query( *db );
 
query.prepare("SELECT username, password FROM db_user WHERE username = :uname and password = :passwd";
query.bindValue( ":uname", uname );
query.bindValue( ":passwd", passwd );
query.exec();

QSqlQuery query( *db );

query.prepare("SELECT username, password FROM db_user WHERE username = :uname and password = :passwd";
query.bindValue( ":uname", uname );
query.bindValue( ":passwd", passwd );
query.exec();

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where uname and passwd are QString. With this SQL driver is worrying about correct building of query.

[squidge]

If you don't know if the query is being build correctly, send it to the debug console using query.lastQuery()

[Lesiok]

If you don't know if the query is being build correctly, send it to the debug console using query.lastQuery()

I know if the query is build correctly or no . What I want to say is that using QSqlQuery::prepare is a good solution for problems with ie. string coding. I don't need to know about code page used by connection to server.