Avoid calling move constructor












13















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?










share|improve this question


















  • 5





    use C++17 :-)...

    – marcinj
    Nov 19 '18 at 19:14






  • 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
    Nov 19 '18 at 19:15








  • 2





    Have you tried removing the =

    – JVApen
    Nov 19 '18 at 19:17






  • 1





    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept

    – Victor Gubin
    Nov 19 '18 at 19:22











  • 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
    Nov 19 '18 at 23:03
















13















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?










share|improve this question


















  • 5





    use C++17 :-)...

    – marcinj
    Nov 19 '18 at 19:14






  • 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
    Nov 19 '18 at 19:15








  • 2





    Have you tried removing the =

    – JVApen
    Nov 19 '18 at 19:17






  • 1





    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept

    – Victor Gubin
    Nov 19 '18 at 19:22











  • 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
    Nov 19 '18 at 23:03














13












13








13


2






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?










share|improve this question














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






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 19 '18 at 19:11









ge45muege45mue

18911




18911








  • 5





    use C++17 :-)...

    – marcinj
    Nov 19 '18 at 19:14






  • 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
    Nov 19 '18 at 19:15








  • 2





    Have you tried removing the =

    – JVApen
    Nov 19 '18 at 19:17






  • 1





    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept

    – Victor Gubin
    Nov 19 '18 at 19:22











  • 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
    Nov 19 '18 at 23:03














  • 5





    use C++17 :-)...

    – marcinj
    Nov 19 '18 at 19:14






  • 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
    Nov 19 '18 at 19:15








  • 2





    Have you tried removing the =

    – JVApen
    Nov 19 '18 at 19:17






  • 1





    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept

    – Victor Gubin
    Nov 19 '18 at 19:22











  • 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
    Nov 19 '18 at 23:03








5




5





use C++17 :-)...

– marcinj
Nov 19 '18 at 19:14





use C++17 :-)...

– marcinj
Nov 19 '18 at 19:14




1




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
Nov 19 '18 at 19:15







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
Nov 19 '18 at 19:15






2




2





Have you tried removing the =

– JVApen
Nov 19 '18 at 19:17





Have you tried removing the =

– JVApen
Nov 19 '18 at 19:17




1




1





And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept

– Victor Gubin
Nov 19 '18 at 19:22





And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept

– Victor Gubin
Nov 19 '18 at 19:22













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
Nov 19 '18 at 23:03





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
Nov 19 '18 at 23:03












2 Answers
2






active

oldest

votes


















14














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").






share|improve this answer



















  • 1





    C++17 demo

    – Kerrek SB
    Nov 19 '18 at 19:15



















5















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.






share|improve this answer


























  • I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.

    – T.C.
    Nov 19 '18 at 22:11











  • @T.C. Wording updated.

    – NathanOliver
    Nov 19 '18 at 22:15











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

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active

oldest

votes









14














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").






share|improve this answer



















  • 1





    C++17 demo

    – Kerrek SB
    Nov 19 '18 at 19:15
















14














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").






share|improve this answer



















  • 1





    C++17 demo

    – Kerrek SB
    Nov 19 '18 at 19:15














14












14








14







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").






share|improve this answer













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").







share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 19 '18 at 19:15









Kerrek SBKerrek SB

367k61690923




367k61690923








  • 1





    C++17 demo

    – Kerrek SB
    Nov 19 '18 at 19:15














  • 1





    C++17 demo

    – Kerrek SB
    Nov 19 '18 at 19:15








1




1





C++17 demo

– Kerrek SB
Nov 19 '18 at 19:15





C++17 demo

– Kerrek SB
Nov 19 '18 at 19:15













5















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.






share|improve this answer


























  • I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.

    – T.C.
    Nov 19 '18 at 22:11











  • @T.C. Wording updated.

    – NathanOliver
    Nov 19 '18 at 22:15
















5















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.






share|improve this answer


























  • I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.

    – T.C.
    Nov 19 '18 at 22:11











  • @T.C. Wording updated.

    – NathanOliver
    Nov 19 '18 at 22:15














5












5








5








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.






share|improve this answer
















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.







share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 19 '18 at 22:14

























answered Nov 19 '18 at 19:17









NathanOliverNathanOliver

92.4k16129195




92.4k16129195













  • I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.

    – T.C.
    Nov 19 '18 at 22:11











  • @T.C. Wording updated.

    – NathanOliver
    Nov 19 '18 at 22:15



















  • I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.

    – T.C.
    Nov 19 '18 at 22:11











  • @T.C. Wording updated.

    – NathanOliver
    Nov 19 '18 at 22:15

















I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.

– T.C.
Nov 19 '18 at 22:11





I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.

– T.C.
Nov 19 '18 at 22:11













@T.C. Wording updated.

– NathanOliver
Nov 19 '18 at 22:15





@T.C. Wording updated.

– NathanOliver
Nov 19 '18 at 22:15


















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