Hi,
I think we use always the copy-initialization for pod types inside Mixxx
(Except initializations lists)
int value = 4;
For me this is the best readable version and is exactly what the underlying
machine code does.
The value 4 is copied from the text segment to a cpu register.
Now we have the new keyword auto.
auto value = 4;
Is readable in the same way, if we assume the every reader
knows what auto is and that literal conts defaults to int.
It forces that the variable is initialized and allows no implicit
conversions.
It may improve readability by hiding unimportant info.
So IMHO we should prefer these both notations over direct-initialization.
If the variable of type class,
QString string("Hallo");
seams to be closest to the underlying assembler.
It has the drawback that it cannot easy be distinguish from a call to a
function
string(). I think thats the reason why we find
QString string = "Hallo";
also in the Mixxx code base.
But this implies s lot of c++ magic and complier optimization.
We should avoid it.
A correct legacy form would be (please correct me)
QString tring = QString("Hallo");
A notation like this:
auto string = QString("Hallo");
may combines the best of the to worlds without any duplication.
Is it OK if we prefer this from now?
Now back to my original Question: "How about CSAMPLE"
I think I still prefer:
CSAMPLE a = 0.0;
If auto is desired and a refactoring towards a complex type likely
auto a = CSAMLE(0.0);
seams to be reasonable.
We should not use
CSAMLPE a(0.0);
Since it is still a POD type
Can this be a common agreement?
Thank you,
Daniel
Am 06.06.2015 um 11:24 schrieb Uwe Klotz:
+1 Gavin, I also prefer direct-initialization over copy-initialization.
For classes without a copy constructor you need to use
direct-initialization anyway. And if you bravely declare your single
parameter constructors as 'explicit' (what you should almost always
do, even if Qt does not) you also need to use direct-initialization.
http://en.cppreference.com/w/cpp/language/direct_initialization
"Direct-initialization is more permissive than copy-initialization:
copy-initialization only considers non-explicit constructors and
user-defined conversion functions, while direct-initialization
considers all constructors and implicit conversion sequences. "
But I must confess that I use the assignment style if the type is
obviously a native type.
Uwe
On 06/06/2015 02:11 AM, Gavin Swanson wrote:
are we in violent agreement then? Why not do the optimal thing in the
first place for consistency sake? Rather than rely on the compiler
to do it for you. Especially in a case like this where the
optimization is no more work nor is it less readable.
On Fri, Jun 5, 2015, 7:38 PM Owen Williams <owilli...@mixxx.org
<mailto:owilli...@mixxx.org>> wrote:
That's what I said?
"The compiler is free to elide (remove) the temporary+copying
whenever
it can, but copy constructor must still be accessible"
On Fri, 2015-06-05 at 23:34 +0000, Gavin Swanson wrote:
> http://stackoverflow.com/a/4470763
>
>
> On Fri, Jun 5, 2015, 7:21 PM Owen Williams <owilli...@mixxx.org
<mailto:owilli...@mixxx.org>>
> wrote:
> Since CSAMPLE is a simple type, assignment is best --
and when
> it works,
> assignment is the way to go (hurray for smart compilers
> eliding copies).
> With the form sample(0.0), it gives the impression that
> CSAMPLE is a
> complex type with a constructor.
>
> On Fri, 2015-06-05 at 22:16 +0000, Gavin Swanson wrote:
> > CSAMPLE sample(0.0);
> >
> >
> > On Fri, Jun 5, 2015, 4:45 PM Owen Williams
> <owilli...@mixxx.org <mailto:owilli...@mixxx.org>>
> > wrote:
> > On Fri, 2015-06-05 at 22:30 +0200, Daniel
Schürmann
> wrote:
> >
> > > CSAMPLE sample = 0.0;
> >
> > This one. auto should really only be used when
> assigning from
> > a
> > function whose return value is obvious.
> >
> >
> >
> >
> >
>
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