Questions tagged [stdmove]
117 questions
2
votes
2 answers
C++ moving a unique_ptr to a struct member
I have the following program -
#include
#include
class Person
{
public:
Person(const std::string& name):
name(name) { }
~Person() { std::cout << "Destroyed" << std::endl; }
std::string…
Jai Prabhu
- 245
- 3
- 10
1
vote
1 answer
How to prevent unique pointers from overlapping
I'm trying to build a timer in C++.
In my Timer class there are two Date objects that hold a std::unique_ptr pointer.
After I std::move the second unique_ptr in the second Date object in the following piece of code, it points to the same…
loremol
- 25
- 4
1
vote
1 answer
C++20 Compiler Error in Visual Studio 2022 Community: Resolving Internal Error C1001
I am facing an issue with C++20 in Visual Studio 2022 Community. The code works correctly in G++ but I get an internal compiler error with MSVC.
Here is the code:
#include
struct Foo {
float* data;
Foo(float * const * const &…
Matt
- 179
- 6
1
vote
2 answers
Why does std::move cause SEGFAULT in this case?
Why does std::move() cause a SEGFAULT in this case?
#include
struct Message {
std::string message;
};
Message * Message_Init(std::string message) {
Message * m = (Message*)calloc(1, sizeof(Message));
m->message =…
Евгений Павлов
- 111
- 6
1
vote
1 answer
Does std::vector "move" implicitly?
Consider the following code:
#include
#include
#include
class Domain {
public:
enum class fieldname {
pos_x, pos_y
};
std::unordered_map>…
P. Nair
- 79
- 7
1
vote
1 answer
return std::move a class with a unique_ptr member
Why can't I return a class containing a std::unique_ptr, using std::move semantics (I thought), as in the example below? I thought that the return would invoke the move ctor of class A, which would std::move the std::unique_ptr. (I'm using GCC 11.2,…
voxoid
- 1,164
- 1
- 14
- 31
1
vote
1 answer
Mixing Rvalue and LValue reference
I'm trying to better understand LValue, RValue, and how std::move works.
I have the following code
#include
class A
{
public:
A() = default;
A(std::string&& aString): myString(std::move(aString)) {}
std::string myString;
};
class…
Evethir
- 31
- 3
1
vote
1 answer
using an initializer list where the values contain unique_ptr member variables
I have a class that contains a unique_ptr. I want to place instances of this class inside a container (specifically std::map). This works using std::move and .emplace however, I would like to perform all this initialization within the container's…
J'e
- 3,014
- 4
- 31
- 55
1
vote
1 answer
getting invalid ouput after std::move of an element from std::list
I'm trying to understand about std::move. In my code I'm moving an element from std::list where struct Data internally contains two std::string fields, but I'm not getting expected output. This is my code:
#include
#include…
Harry
- 2,177
- 1
- 19
- 33
1
vote
2 answers
Why move ctor is not called in this case?
#include
using namespace std;
class Test {
public:
Test(string value){
cout<<"Ctor "<
HDenied
- 37
- 6
1
vote
2 answers
Can I avoid copies when returning multiple values, while keeping my return type?
If we write the following function:
auto foo() {
Foo foo { /* ... */ };
do_stuff(foo);
return foo;
}
then NRVO should kick in, so that foo does not get copied on return.
Now suppose I want to return two different values:
auto foo() {
…
einpoklum
- 118,144
- 57
- 340
- 684
1
vote
1 answer
Right values as function argument, correct usage?
Trying to use rightvalues a bit more but I got confused, how should I design my function in which I want to use the right value:
// Pass by whatever-it's-called
void RockyBalboa::DoSomething(std::string&& str){
m_fighters.push_back(str);
}
//…
dejoma
- 394
- 1
- 6
- 18
1
vote
2 answers
Why am I getting a const reference when I for(auto& it : myUnorderedMap) {... = std::move(it.second)}?
Minimally reproducible example cpp.sh/2nlzz :
#include
#include
#include
#include
using namespace std;
int main()
{
struct Movable {
Movable() = default;
Movable ( Movable && ) = default; //…
matthias_buehlmann
- 4,641
- 6
- 34
- 76
1
vote
1 answer
How to route to different implementations according to whether an object is a rvalue reference or not?
For example, I have a class called MyClass and create an instance from it:
auto obj = MyClass()
I have two ways to call its method.
Option 1: call the method directly
obj.method()
Option 2: cast obj to rvalue reference first, then call the…
Hanfei Sun
- 45,281
- 39
- 129
- 237
1
vote
2 answers
Casting to rvalue reference to "force" a move in a return value - clarification
Ok, I am starting to get the jist of rvalue references (I think). I have this code snippet that I was writing:
#include
using namespace std;
std::string get_string()
{
std::string str{"here is your string\n"};
return std::move(str);…
code_fodder
- 15,263
- 17
- 90
- 167