Struct beeing moved around

[Sean Kelly]

On May 20, 2011, at 8:43 AM, so wrote:

> On Fri, 20 May 2011 17:30:33 +0300, Sean Kelly <sean at invisibleduck.org> wrote:
> 
>> In main above you're declaring a new struct variable t which is default-constructed, then a temporary is created and initialized to 5, and then the temporary is copied onto t.  It does seem like a postblit should probably occur in this scenario though.
> 
> I am confused.
> There shouldn't be any copying, it is construction.

If you do the following:

    MyStruct s;

A new instance of MyStruct is be created and default-initialized.  Changing this to:

    MyStruct s = MyStruct(5);

Is really just shorthand for:

    MyStruct s;
    s = MyStruct(5);

The compiler can translate this into a single construction (it does in C++), but I don't know that it's required to.