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I ran into this issue the other day when writing a large class that needs
additional book-keeping logic when being moved or copied. All fields could
be copied/moved normally (just as the default versions would do), there was
just a few extra function calls that needed to be made to sort things out.
Whenever I added/removed fields in the class, I would have to reflect those
changes in all my constructors, which became both bug-prone and a hassle.
If there was a simple way to create a default move/copy constructor with
some additional behavior in the body, that would be wonderful. Something
along the lines of this:

MyType::MyType(const MyType& copy)
    : default(copy)
{
    // Additional logic
}

The constructor would then copy-construct all fields automatically, as well
as running the additional code in the body. A copy-assignment operator
could be implemented as such:

MyType& operator=(const MyType& copy)
{
    if (this != &copy)
    {
        default(copy);
        // Addition logic
    }
    return *this;
}

Both examples could be easily extended to move construction/assignment as
well.

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<div dir=3D"ltr">I ran into this issue the other day when writing a large c=
lass that needs additional book-keeping logic when being moved or copied. A=
ll fields could be copied/moved normally (just as the default versions woul=
d do), there was just a few extra function calls that needed to be made to =
sort things out. Whenever I added/removed fields in the class, I would have=
 to reflect those changes in all my constructors, which became both bug-pro=
ne and a hassle. If there was a simple way to create a default move/copy co=
nstructor with some additional behavior in the body, that would be wonderfu=
l. Something along the lines of this:<br><br><div class=3D"prettyprint" sty=
le=3D"background-color: rgb(250, 250, 250); border-color: rgb(187, 187, 187=
); border-style: solid; border-width: 1px; word-wrap: break-word;"><code cl=
ass=3D"prettyprint"><div class=3D"subprettyprint"><span style=3D"color: #60=
6;" class=3D"styled-by-prettify">MyType</span><span style=3D"color: #660;" =
class=3D"styled-by-prettify">::</span><span style=3D"color: #606;" class=3D=
"styled-by-prettify">MyType</span><span style=3D"color: #660;" class=3D"sty=
led-by-prettify">(</span><span style=3D"color: #008;" class=3D"styled-by-pr=
ettify">const</span><span style=3D"color: #000;" class=3D"styled-by-prettif=
y"> </span><span style=3D"color: #606;" class=3D"styled-by-prettify">MyType=
</span><span style=3D"color: #660;" class=3D"styled-by-prettify">&amp;</spa=
n><span style=3D"color: #000;" class=3D"styled-by-prettify"> copy</span><sp=
an style=3D"color: #660;" class=3D"styled-by-prettify">)</span><span style=
=3D"color: #000;" class=3D"styled-by-prettify"><br>&nbsp; &nbsp; </span><sp=
an style=3D"color: #660;" class=3D"styled-by-prettify">:</span><span style=
=3D"color: #000;" class=3D"styled-by-prettify"> </span><span style=3D"color=
: #008;" class=3D"styled-by-prettify">default</span><span style=3D"color: #=
660;" class=3D"styled-by-prettify">(</span><span style=3D"color: #000;" cla=
ss=3D"styled-by-prettify">copy</span><span style=3D"color: #660;" class=3D"=
styled-by-prettify">)</span><span style=3D"color: #000;" class=3D"styled-by=
-prettify"><br></span><span style=3D"color: #660;" class=3D"styled-by-prett=
ify">{</span><span style=3D"color: #000;" class=3D"styled-by-prettify"><br>=
&nbsp; &nbsp; </span><span style=3D"color: #800;" class=3D"styled-by-pretti=
fy">// Additional logic</span><span style=3D"color: #000;" class=3D"styled-=
by-prettify"><br></span><span style=3D"color: #660;" class=3D"styled-by-pre=
ttify">}</span><span style=3D"color: #000;" class=3D"styled-by-prettify"><b=
r></span></div></code></div><br>The constructor would then copy-construct a=
ll fields automatically, as well as running the additional code in the body=
.. A copy-assignment operator could be implemented as such:<br><br><div clas=
s=3D"prettyprint" style=3D"background-color: rgb(250, 250, 250); border-col=
or: rgb(187, 187, 187); border-style: solid; border-width: 1px; word-wrap: =
break-word;"><code class=3D"prettyprint"><div class=3D"subprettyprint"><spa=
n style=3D"color: #606;" class=3D"styled-by-prettify">MyType</span><span st=
yle=3D"color: #660;" class=3D"styled-by-prettify">&amp;</span><span style=
=3D"color: #000;" class=3D"styled-by-prettify"> </span><span style=3D"color=
: #008;" class=3D"styled-by-prettify">operator</span><span style=3D"color: =
#660;" class=3D"styled-by-prettify">=3D(</span><span style=3D"color: #008;"=
 class=3D"styled-by-prettify">const</span><span style=3D"color: #000;" clas=
s=3D"styled-by-prettify"> </span><span style=3D"color: #606;" class=3D"styl=
ed-by-prettify">MyType</span><span style=3D"color: #660;" class=3D"styled-b=
y-prettify">&amp;</span><span style=3D"color: #000;" class=3D"styled-by-pre=
ttify"> copy</span><span style=3D"color: #660;" class=3D"styled-by-prettify=
">)</span><span style=3D"color: #000;" class=3D"styled-by-prettify"><br></s=
pan><span style=3D"color: #660;" class=3D"styled-by-prettify">{</span><span=
 style=3D"color: #000;" class=3D"styled-by-prettify"><br>&nbsp; &nbsp; </sp=
an><span style=3D"color: #008;" class=3D"styled-by-prettify">if</span><span=
 style=3D"color: #000;" class=3D"styled-by-prettify"> </span><span style=3D=
"color: #660;" class=3D"styled-by-prettify">(</span><span style=3D"color: #=
008;" class=3D"styled-by-prettify">this</span><span style=3D"color: #000;" =
class=3D"styled-by-prettify"> </span><span style=3D"color: #660;" class=3D"=
styled-by-prettify">!=3D</span><span style=3D"color: #000;" class=3D"styled=
-by-prettify"> </span><span style=3D"color: #660;" class=3D"styled-by-prett=
ify">&amp;</span><span style=3D"color: #000;" class=3D"styled-by-prettify">=
copy</span><span style=3D"color: #660;" class=3D"styled-by-prettify">)</spa=
n><span style=3D"color: #000;" class=3D"styled-by-prettify"><br>&nbsp; &nbs=
p; </span><span style=3D"color: #660;" class=3D"styled-by-prettify">{</span=
><span style=3D"color: #000;" class=3D"styled-by-prettify"><br>&nbsp; &nbsp=
; &nbsp; &nbsp; </span><span style=3D"color: #008;" class=3D"styled-by-pret=
tify">default</span><span style=3D"color: #660;" class=3D"styled-by-prettif=
y">(</span><span style=3D"color: #000;" class=3D"styled-by-prettify">copy</=
span><span style=3D"color: #660;" class=3D"styled-by-prettify">);</span><sp=
an style=3D"color: #000;" class=3D"styled-by-prettify"><br>&nbsp; &nbsp; &n=
bsp; &nbsp; </span><span style=3D"color: #800;" class=3D"styled-by-prettify=
">// Addition logic</span><span style=3D"color: #000;" class=3D"styled-by-p=
rettify"><br>&nbsp; &nbsp; </span><span style=3D"color: #660;" class=3D"sty=
led-by-prettify">}</span><span style=3D"color: #000;" class=3D"styled-by-pr=
ettify"><br>&nbsp; &nbsp; </span><span style=3D"color: #008;" class=3D"styl=
ed-by-prettify">return</span><span style=3D"color: #000;" class=3D"styled-b=
y-prettify"> </span><span style=3D"color: #660;" class=3D"styled-by-prettif=
y">*</span><span style=3D"color: #008;" class=3D"styled-by-prettify">this</=
span><span style=3D"color: #660;" class=3D"styled-by-prettify">;</span><spa=
n style=3D"color: #000;" class=3D"styled-by-prettify"><br></span><span styl=
e=3D"color: #660;" class=3D"styled-by-prettify">}</span><span style=3D"colo=
r: #000;" class=3D"styled-by-prettify"><br></span></div></code></div><br>Bo=
th examples could be easily extended to move construction/assignment as wel=
l.<br><br></div>

<p></p>

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/a>.<br />

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