Could someone pinpoint me to the status of
enabling the use of std::tie with non-default ctor objects as in the
following example?

struct foo
{
  foo(int a) : a_(a) {}
  int a_;
};

std::pair<bool, foo> my_function()
{
  return { false, foo(1) };
};

foo my_foo; // Compiler errror, as no default ctor available
bool state;
std::tie<state, my_foo> = my_function();

I remember there were several proposals to tackle this problem somehow,
but couldn't find them.

Thanks,
r.

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=D0=BF=D1=8F=D1=82=D0=BD=D0=B8=D1=86=D0=B0, 8 =D0=B8=D1=8E=D0=BB=D1=8F 2016=
 =D0=B3., 14:07:55 UTC+6 =D0=BF=D0=BE=D0=BB=D1=8C=D0=B7=D0=BE=D0=B2=D0=B0=
=D1=82=D0=B5=D0=BB=D1=8C Robert Jakob =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=
=D0=BB:
>
> Could someone pinpoint me to the status of=20
> enabling the use of std::tie with non-default ctor objects as in the=20
> following example?=20
>
> struct foo=20
> {=20
>   foo(int a) : a_(a) {}=20
>   int a_;=20
> };=20
>
> std::pair<bool, foo> my_function()=20
> {=20
>   return { false, foo(1) };=20
> };=20
>
> foo my_foo; // Compiler errror, as no default ctor available=20
> bool state;=20
> std::tie<state, my_foo> =3D my_function();=20
>
> I remember there were several proposals to tackle this problem somehow,=
=20
> but couldn't find them.=20
>
> Thanks,=20
> r.=20
>

Structured binding:
auto [state, my_foo] =3D my_function();

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0217r2.html=20
included into C++17 draft on july committee meeting

Sergey=20

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<div dir=3D"ltr">=D0=BF=D1=8F=D1=82=D0=BD=D0=B8=D1=86=D0=B0, 8 =D0=B8=D1=8E=
=D0=BB=D1=8F 2016 =D0=B3., 14:07:55 UTC+6 =D0=BF=D0=BE=D0=BB=D1=8C=D0=B7=D0=
=BE=D0=B2=D0=B0=D1=82=D0=B5=D0=BB=D1=8C Robert Jakob =D0=BD=D0=B0=D0=BF=D0=
=B8=D1=81=D0=B0=D0=BB:<blockquote class=3D"gmail_quote" style=3D"margin: 0;=
margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;">Could so=
meone pinpoint me to the status of
<br>enabling the use of std::tie with non-default ctor objects as in the
<br>following example?
<br>
<br>struct foo
<br>{
<br>=C2=A0 foo(int a) : a_(a) {}
<br>=C2=A0 int a_;
<br>};
<br>
<br>std::pair&lt;bool, foo&gt; my_function()
<br>{
<br>=C2=A0 return { false, foo(1) };
<br>};
<br>
<br>foo my_foo; // Compiler errror, as no default ctor available
<br>bool state;
<br>std::tie&lt;state, my_foo&gt; =3D my_function();
<br>
<br>I remember there were several proposals to tackle this problem somehow,
<br>but couldn&#39;t find them.
<br>
<br>Thanks,
<br>r.
<br></blockquote><div><br>Structured binding:<br><div class=3D"prettyprint"=
 style=3D"background-color: rgb(250, 250, 250); border-color: rgb(187, 187,=
 187); border-style: solid; border-width: 1px; word-wrap: break-word;"><cod=
e class=3D"prettyprint"><div class=3D"subprettyprint"><span style=3D"color:=
 #008;" class=3D"styled-by-prettify">auto</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: #000;" class=3D"style=
d-by-prettify">state</span><span style=3D"color: #660;" class=3D"styled-by-=
prettify">,</span><span style=3D"color: #000;" class=3D"styled-by-prettify"=
> my_foo</span><span style=3D"color: #660;" class=3D"styled-by-prettify">]<=
/span><span style=3D"color: #000;" class=3D"styled-by-prettify"> </span><sp=
an style=3D"color: #660;" class=3D"styled-by-prettify">=3D</span><span styl=
e=3D"color: #000;" class=3D"styled-by-prettify"> my_function</span><span st=
yle=3D"color: #660;" class=3D"styled-by-prettify">();</span><span style=3D"=
color: #000;" class=3D"styled-by-prettify"><br></span></div></code></div><b=
r>http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0217r2.html incl=
uded into C++17 draft on july committee meeting<br><br>Sergey <br></div></d=
iv>

<p></p>

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40isocpp.org?utm_medium=3Demail&utm_source=3Dfooter">https://groups.google.=
com/a/isocpp.org/d/msgid/std-proposals/6caa738a-2e27-47ba-84ee-e6b7f73f66b3=
%40isocpp.org</a>.<br />

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