Re: Microsoft C++ Exception std::out_of_range mysql-connector-c++-8.0.18-winx64

[Rafal Somla]

Hi,

Indeed in common/result.h, in method Row_impl<VAL>::get() we have this non-orthodox code that uses std::out_of_range exception to detect if given field in the row was already cached in m_vals member or not:

try {
..return m_vals.at(pos);
}
catch (const std::out_of_range&)
{
..if (!m_mdata)
....throw;
..const Format_info &fi = m_mdata->get_format(pos);
..convert_at(pos, fi);
..return m_vals.at(pos);
}

The intention is that this out_of_range exception should be thrown only first time given field is accessed, later m_vals.at(pos) should return the value without any further processing. This is why in debug session you see the exceptions being thrown and yes, it can disrupt a debug session a bit. I am not claiming this is the most efficient or the most elegant code, but it is what we have and it worked good enough for us so far.

Btw. We are fixing our code to build seamlessly with VS2019, so watch out for the upcoming release!