Avoid calling move constructor
up vote
13
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?
c++ c++11 c++17
asked Nov 19 at 19:11
Zlatan
14810
add a comment |
up vote
13
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?
c++ c++11 c++17
asked Nov 19 at 19:11
Zlatan
14810
5
use C++17 :-)...
– marcinj
Nov 19 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 at 19:15
2
Have you tried removing the=
– JVApen
Nov 19 at 19:17
1
Andconstexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
Nov 19 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 at 23:03
add a comment |
up vote
13
down vote
favorite
up vote
13
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?
c++ c++11 c++17
asked Nov 19 at 19:11
Zlatan
14810
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
c++ c++11 c++17
asked Nov 19 at 19:11
Zlatan
14810
asked Nov 19 at 19:11
Zlatan
14810
asked Nov 19 at 19:11
Zlatan
14810
asked Nov 19 at 19:11
Zlatan
14810
asked Nov 19 at 19:11
Zlatan
14810
14810
5
use C++17 :-)...
– marcinj
Nov 19 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 at 19:15
2
Have you tried removing the=
– JVApen
Nov 19 at 19:17
1
Andconstexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
Nov 19 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 at 23:03
add a comment |
5
use C++17 :-)...
– marcinj
Nov 19 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 at 19:15
2
Have you tried removing the=
– JVApen
Nov 19 at 19:17
1
Andconstexpr FooC(uint16_t iPort, uint16_t iPin) noexcept
– Victor Gubin
Nov 19 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 at 23:03
5
5
use C++17 :-)...
– marcinj
Nov 19 at 19:14
use C++17 :-)...
– marcinj
Nov 19 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 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 at 19:15
2
2
Have you tried removing the
=– JVApen
Nov 19 at 19:17
Have you tried removing the
=– JVApen
Nov 19 at 19:17
1
1
And
constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept– Victor Gubin
Nov 19 at 19:22
And
constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept– Victor Gubin
Nov 19 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 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 at 23:03
add a comment |
2 Answers
2
active
oldest
votes
up vote
14
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 Nov 19 at 19:15
Kerrek SB
361k61677914
1
C++17 demo
– Kerrek SB
Nov 19 at 19:15
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.
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
Nov 19 at 22:11
@T.C. Wording updated.
– NathanOliver
Nov 19 at 22:15
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
14
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 Nov 19 at 19:15
Kerrek SB
361k61677914
1
C++17 demo
– Kerrek SB
Nov 19 at 19:15
add a comment |
up vote
14
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 Nov 19 at 19:15
Kerrek SB
361k61677914
1
C++17 demo
– Kerrek SB
Nov 19 at 19:15
add a comment |
up vote
14
down vote
up vote
14
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 Nov 19 at 19:15
Kerrek SB
361k61677914
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 Nov 19 at 19:15
Kerrek SB
361k61677914
answered Nov 19 at 19:15
Kerrek SB
361k61677914
answered Nov 19 at 19:15
Kerrek SB
361k61677914
answered Nov 19 at 19:15
Kerrek SB
361k61677914
361k61677914
1
C++17 demo
– Kerrek SB
Nov 19 at 19:15
add a comment |
1
C++17 demo
– Kerrek SB
Nov 19 at 19:15
1
1
C++17 demo
– Kerrek SB
Nov 19 at 19:15
C++17 demo
– Kerrek SB
Nov 19 at 19:15
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.
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
Nov 19 at 22:11
@T.C. Wording updated.
– NathanOliver
Nov 19 at 22:15
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.
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
Nov 19 at 22:11
@T.C. Wording updated.
– NathanOliver
Nov 19 at 22:15
add a comment |
up vote
5
down vote
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.
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
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.
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
edited Nov 19 at 22:14
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
answered Nov 19 at 19:17
NathanOliver
85.5k15118177
85.5k15118177
I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
Nov 19 at 22:11
@T.C. Wording updated.
– NathanOliver
Nov 19 at 22:15
add a comment |
I'd be careful with the phrasing here. Your pre-C++17 example is copy-list-initializing the elements.
– T.C.
Nov 19 at 22:11
@T.C. Wording updated.
– NathanOliver
Nov 19 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 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 at 22:11
@T.C. Wording updated.
– NathanOliver
Nov 19 at 22:15
@T.C. Wording updated.
– NathanOliver
Nov 19 at 22:15
add a comment |
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5
use C++17 :-)...
– marcinj
Nov 19 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 at 19:15
2
Have you tried removing the
=– JVApen
Nov 19 at 19:17
1
And
constexpr FooC(uint16_t iPort, uint16_t iPin) noexcept– Victor Gubin
Nov 19 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 at 23:03