Avoid calling move constructor

up vote
11
down vote

favorite

I have following example

#include <cstdint>



class FooC

{

public:

   FooC(uint16_t iPort, uint16_t iPin)

   : PORT(iPort)

   , PIN(iPin)

   {

   };



   ~FooC() = default;



   FooC() = delete;

   FooC(const FooC&) = delete;

   FooC(FooC&&) = delete;



private:

   const uint16_t PORT;

   const uint16_t PIN;

};



int main()

{

    FooC array[2] = {

       FooC(1,2),

       FooC(3,4)

    };

}

and I don't want to call the default, move and copy constructor. Due to that I deleted the functions. Unfortunately this results in following error (compiled with C++11)

: In function 'int main()':

:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
Compiler returned: 1

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

asked 2 days ago

Zlatan

1409

5

use C++17 :-)...
– marcinj
2 days ago

1

Since you've deleted default copy and move constructors (as well as assignment oprators) your class is no longer movable and copyable, when your program expecting move assignable class.
– Victor Gubin
2 days ago

2

Have you tried removing the =
– JVApen
2 days ago

1

And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
2 days ago

Note that you don't need to delete the move-constructor: when you delete the copy-constructor, the move-constructor is not implicitly generated
– M.M
2 days ago

add a comment |

up vote
11
down vote

favorite

I have following example

#include <cstdint>



class FooC

{

public:

   FooC(uint16_t iPort, uint16_t iPin)

   : PORT(iPort)

   , PIN(iPin)

   {

   };



   ~FooC() = default;



   FooC() = delete;

   FooC(const FooC&) = delete;

   FooC(FooC&&) = delete;



private:

   const uint16_t PORT;

   const uint16_t PIN;

};



int main()

{

    FooC array[2] = {

       FooC(1,2),

       FooC(3,4)

    };

}

and I don't want to call the default, move and copy constructor. Due to that I deleted the functions. Unfortunately this results in following error (compiled with C++11)

: In function 'int main()':

:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
Compiler returned: 1

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

asked 2 days ago

Zlatan

1409

5

use C++17 :-)...
– marcinj
2 days ago

1

Since you've deleted default copy and move constructors (as well as assignment oprators) your class is no longer movable and copyable, when your program expecting move assignable class.
– Victor Gubin
2 days ago

2

Have you tried removing the =
– JVApen
2 days ago

1

And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
2 days ago

Note that you don't need to delete the move-constructor: when you delete the copy-constructor, the move-constructor is not implicitly generated
– M.M
2 days ago

add a comment |

up vote
11
down vote

favorite

I have following example

#include <cstdint>



class FooC

{

public:

   FooC(uint16_t iPort, uint16_t iPin)

   : PORT(iPort)

   , PIN(iPin)

   {

   };



   ~FooC() = default;



   FooC() = delete;

   FooC(const FooC&) = delete;

   FooC(FooC&&) = delete;



private:

   const uint16_t PORT;

   const uint16_t PIN;

};



int main()

{

    FooC array[2] = {

       FooC(1,2),

       FooC(3,4)

    };

}

and I don't want to call the default, move and copy constructor. Due to that I deleted the functions. Unfortunately this results in following error (compiled with C++11)

: In function 'int main()':

:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
Compiler returned: 1

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

asked 2 days ago

Zlatan

1409

I have following example

#include <cstdint>



class FooC

{

public:

   FooC(uint16_t iPort, uint16_t iPin)

   : PORT(iPort)

   , PIN(iPin)

   {

   };



   ~FooC() = default;



   FooC() = delete;

   FooC(const FooC&) = delete;

   FooC(FooC&&) = delete;



private:

   const uint16_t PORT;

   const uint16_t PIN;

};



int main()

{

    FooC array[2] = {

       FooC(1,2),

       FooC(3,4)

    };

}

and I don't want to call the default, move and copy constructor. Due to that I deleted the functions. Unfortunately this results in following error (compiled with C++11)

: In function 'int main()':

:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
:28:5: error: use of deleted function 'FooC::FooC(FooC&&)'
 };



 ^
:16:4: note: declared here
FooC(FooC&&) = delete;



^~~~
Compiler returned: 1

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

c++ c++11 c++17

asked 2 days ago

Zlatan

1409

asked 2 days ago

Zlatan

1409

asked 2 days ago

Zlatan

1409

asked 2 days ago

Zlatan

1409

asked 2 days ago

Zlatan

1409

5

use C++17 :-)...
– marcinj
2 days ago

1

Since you've deleted default copy and move constructors (as well as assignment oprators) your class is no longer movable and copyable, when your program expecting move assignable class.
– Victor Gubin
2 days ago

2

Have you tried removing the =
– JVApen
2 days ago

1

And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
2 days ago

Note that you don't need to delete the move-constructor: when you delete the copy-constructor, the move-constructor is not implicitly generated
– M.M
2 days ago

add a comment |

5

use C++17 :-)...
– marcinj
2 days ago

1

Since you've deleted default copy and move constructors (as well as assignment oprators) your class is no longer movable and copyable, when your program expecting move assignable class.
– Victor Gubin
2 days ago

2

Have you tried removing the =
– JVApen
2 days ago

1

And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
2 days ago

Note that you don't need to delete the move-constructor: when you delete the copy-constructor, the move-constructor is not implicitly generated
– M.M
2 days ago

use C++17 :-)...
– marcinj
2 days ago

Since you've deleted default copy and move constructors (as well as assignment oprators) your class is no longer movable and copyable, when your program expecting move assignable class.
– Victor Gubin
2 days ago

Have you tried removing the =
– JVApen
2 days ago

And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
2 days ago

Note that you don't need to delete the move-constructor: when you delete the copy-constructor, the move-constructor is not implicitly generated
– M.M
2 days ago

add a comment |

2 Answers
2

active

oldest

votes

up vote
13
down vote

In C++11 and C++14, you can use nested braces:

FooC array[2] = {{1,2}, {3,4}};

In C++17 your code should already work as written thanks to the new prvalue/materialization rules ("guaranteed copy elision").

answered 2 days ago

Kerrek SB

359k60674910

1

C++17 demo
– Kerrek SB
2 days ago

add a comment |

up vote
5
down vote

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

No with your current syntax (before C++17) and yes (in C++17).

Pre-C++17:

This is not possible. The aggregate initialization copies the initializers into the aggregate. This means you have to have an accessible copy/move constructor. In C++11 you have to pass the constructor parameters as their own braced-init-list. This means you aren't copying FooC's but instead copy-list-initializing the FooC's in the array which calls the 2 parameter constructor instead of the copy/move constructor.

FooC array[2] = {

   {1, 2},

   {3, 4}

};

C++17:

You no longer have temporary objects in the braced-init-list and each element of the array will be directly initialized instead of copy initialized.

edited 2 days ago

answered 2 days ago

NathanOliver

82.7k15112172

I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
2 days ago

@T.C. Wording updated.
– NathanOliver
2 days ago

add a comment |

Your Answer

StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});

}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53381152%2favoid-calling-move-constructor%23new-answer', 'question_page');
}
);

Post as a guest

Name

Required, but never shown

2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
13
down vote

In C++11 and C++14, you can use nested braces:

FooC array[2] = {{1,2}, {3,4}};

In C++17 your code should already work as written thanks to the new prvalue/materialization rules ("guaranteed copy elision").

answered 2 days ago

Kerrek SB

359k60674910

1

C++17 demo
– Kerrek SB
2 days ago

add a comment |

up vote
13
down vote

In C++11 and C++14, you can use nested braces:

FooC array[2] = {{1,2}, {3,4}};

In C++17 your code should already work as written thanks to the new prvalue/materialization rules ("guaranteed copy elision").

answered 2 days ago

Kerrek SB

359k60674910

1

C++17 demo
– Kerrek SB
2 days ago

add a comment |

up vote
13
down vote

In C++11 and C++14, you can use nested braces:

FooC array[2] = {{1,2}, {3,4}};

In C++17 your code should already work as written thanks to the new prvalue/materialization rules ("guaranteed copy elision").

answered 2 days ago

Kerrek SB

359k60674910

In C++11 and C++14, you can use nested braces:

FooC array[2] = {{1,2}, {3,4}};

In C++17 your code should already work as written thanks to the new prvalue/materialization rules ("guaranteed copy elision").

answered 2 days ago

Kerrek SB

359k60674910

answered 2 days ago

Kerrek SB

359k60674910

answered 2 days ago

Kerrek SB

359k60674910

answered 2 days ago

Kerrek SB

359k60674910

1

C++17 demo
– Kerrek SB
2 days ago

add a comment |

1

C++17 demo
– Kerrek SB
2 days ago

C++17 demo
– Kerrek SB
2 days ago

add a comment |

up vote
5
down vote

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

No with your current syntax (before C++17) and yes (in C++17).

Pre-C++17:

FooC array[2] = {

   {1, 2},

   {3, 4}

};

C++17:

You no longer have temporary objects in the braced-init-list and each element of the array will be directly initialized instead of copy initialized.

edited 2 days ago

answered 2 days ago

NathanOliver

82.7k15112172

I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
2 days ago

@T.C. Wording updated.
– NathanOliver
2 days ago

add a comment |

up vote
5
down vote

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

No with your current syntax (before C++17) and yes (in C++17).

Pre-C++17:

FooC array[2] = {

   {1, 2},

   {3, 4}

};

C++17:

You no longer have temporary objects in the braced-init-list and each element of the array will be directly initialized instead of copy initialized.

edited 2 days ago

answered 2 days ago

NathanOliver

82.7k15112172

I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
2 days ago

@T.C. Wording updated.
– NathanOliver
2 days ago

add a comment |

up vote
5
down vote

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

No with your current syntax (before C++17) and yes (in C++17).

Pre-C++17:

FooC array[2] = {

   {1, 2},

   {3, 4}

};

C++17:

You no longer have temporary objects in the braced-init-list and each element of the array will be directly initialized instead of copy initialized.

edited 2 days ago

answered 2 days ago

NathanOliver

82.7k15112172

Is it possible to force in this example the calling of constructor with the parameters and still delete the default, move and copy constructor?

No with your current syntax (before C++17) and yes (in C++17).

Pre-C++17:

FooC array[2] = {

   {1, 2},

   {3, 4}

};

C++17:

You no longer have temporary objects in the braced-init-list and each element of the array will be directly initialized instead of copy initialized.

edited 2 days ago

answered 2 days ago

NathanOliver

82.7k15112172

edited 2 days ago

answered 2 days ago

NathanOliver

82.7k15112172

answered 2 days ago

NathanOliver

82.7k15112172

answered 2 days ago

NathanOliver

82.7k15112172

I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
2 days ago

@T.C. Wording updated.
– NathanOliver
2 days ago

add a comment |

I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
2 days ago

@T.C. Wording updated.
– NathanOliver
2 days ago

I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
2 days ago

@T.C. Wording updated.
– NathanOliver
2 days ago

add a comment |

draft saved

draft discarded

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Name

Required, but never shown

Name

Required, but never shown

This page is only for reference, If you need detailed information, please check here

Search This Blog

Ufyukyu