Boost logo

Boost :

From: Yuval Ronen (ronen_yuval_at_[hidden])
Date: 2005-12-23 18:18:35

Frank Laub wrote:
> I hadn't realized that this was an improper usage of optional. I returned
> 'false' because it felt like a 'natural' thing to return as that of a
> failure. Because the compiler and my tests showed this to work, I figured
> optional had a special bool constructor or something. I've noticed others
> use a 'none' type. I suppose the default ctor is the preferred way?

AFAIK, there's no difference between the default constructor and the
'none' constructor. They both construct the optional in the
'un-initialized' state, and you can use whichever you want. Using any
other constructor (copy constructor aside) would try to construct the
optional's value_type using the argument to the constructor, and put the
optional in an 'initialized' state.

Sending 'false' as a constructor argument falls into the second
category, which is not what you wanted...

> Thanks for the heads up.

My pleasure.

Boost list run by bdawes at, gregod at, cpdaniel at, john at