From: Warren Young
Date: September 8 2010 9:11pm
Subject: Re: mysqlpp::sql_set and mysql_sql_set_null compiler errors
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On 9/8/2010 2:23 PM, Adrian Cornish wrote:
>
> I cannot compile even a simple example using sets?

It's not a very popular part of MySQL++, so you might be the first 
person to either find this particular bug, or at least care enough about 
it to report it.

> Can someone point
> me at the obvious errors I must doing.

You failed to patch MySQL++ to support this use case. :)

If you look down at the bottom of lib/myset.h, you'll see an absence of 
a template specialization for mysqlpp::Set.  I think adding one will fix 
your problem.  It looks easy to add, but I'd rather you did it, since as 
far as I know, you're the only client for that code.

> I dont understand why its trying to apply conversion.

The conversion from const char* is because all data comes from the MySQL 
server as C strings.

The attempt to convert from that to unsigned long is the actual error. 
I'm pretty sure the compiler is trying that because it's the 
fall-through case, allowing us to get away without providing explicit 
conversion paths for all the many integral types, including things like 
bool.