From: Warren Young
Date: May 18 2010 12:53am
Subject: Re: Detecting errors executing SQL queries
List-Archive: http://lists.mysql.com/plusplus/8949
Message-Id: <4BF1E503.5000409@etr-usa.com>
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On 6/10/2009 2:54 AM, Warren Young wrote:
> Martin Dubuc wrote:
>> I expected that the !query would work, but the
>> compiler must do something special because the !query doesn't work.
>
> This behavior is very weird. It must be going through some other
> conversion path, perhaps one inherited from std::ostream.

For the archives, it was due to basic_ios::operator!().  MySQL++ 3.1 
overrides this with Query::operator!(), which fixes this.

Incidentally, this works in MySQL++ 3.0:

	if (query) { ...

It's because that calls Query::operator void*() instead of 
basic_ios::operator!().