Avoid calling move constructor











up vote
9
down vote

favorite
1












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
    yesterday






  • 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
    yesterday








  • 2




    Have you tried removing the =
    – JVApen
    yesterday






  • 1




    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
    – Victor Gubin
    yesterday










  • 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
    yesterday















up vote
9
down vote

favorite
1












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
    yesterday






  • 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
    yesterday








  • 2




    Have you tried removing the =
    – JVApen
    yesterday






  • 1




    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
    – Victor Gubin
    yesterday










  • 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
    yesterday













up vote
9
down vote

favorite
1









up vote
9
down vote

favorite
1






1





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 yesterday









Zlatan

1308




1308








  • 5




    use C++17 :-)...
    – marcinj
    yesterday






  • 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
    yesterday








  • 2




    Have you tried removing the =
    – JVApen
    yesterday






  • 1




    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
    – Victor Gubin
    yesterday










  • 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
    yesterday














  • 5




    use C++17 :-)...
    – marcinj
    yesterday






  • 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
    yesterday








  • 2




    Have you tried removing the =
    – JVApen
    yesterday






  • 1




    And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
    – Victor Gubin
    yesterday










  • 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
    yesterday








5




5




use C++17 :-)...
– marcinj
yesterday




use C++17 :-)...
– marcinj
yesterday




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
yesterday






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
yesterday






2




2




Have you tried removing the =
– JVApen
yesterday




Have you tried removing the =
– JVApen
yesterday




1




1




And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
yesterday




And constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
yesterday












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
yesterday




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
yesterday












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").






share|improve this answer

















  • 1




    C++17 demo
    – Kerrek SB
    yesterday


















up vote
4
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.






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.
    yesterday










  • @T.C. Wording updated.
    – NathanOliver
    yesterday











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






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").






share|improve this answer

















  • 1




    C++17 demo
    – Kerrek SB
    yesterday















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").






share|improve this answer

















  • 1




    C++17 demo
    – Kerrek SB
    yesterday













up vote
13
down vote










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").






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 yesterday









Kerrek SB

359k60673909




359k60673909








  • 1




    C++17 demo
    – Kerrek SB
    yesterday














  • 1




    C++17 demo
    – Kerrek SB
    yesterday








1




1




C++17 demo
– Kerrek SB
yesterday




C++17 demo
– Kerrek SB
yesterday












up vote
4
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.






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.
    yesterday










  • @T.C. Wording updated.
    – NathanOliver
    yesterday















up vote
4
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.






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.
    yesterday










  • @T.C. Wording updated.
    – NathanOliver
    yesterday













up vote
4
down vote










up vote
4
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.






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 yesterday

























answered yesterday









NathanOliver

82.5k15111172




82.5k15111172












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










  • @T.C. Wording updated.
    – NathanOliver
    yesterday


















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










  • @T.C. Wording updated.
    – NathanOliver
    yesterday
















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




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












@T.C. Wording updated.
– NathanOliver
yesterday




@T.C. Wording updated.
– NathanOliver
yesterday


















 

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