зеркало из
https://github.com/iharh/notes.git
synced 2025-10-31 05:36:08 +02:00
146 строки
4.3 KiB
Plaintext
146 строки
4.3 KiB
Plaintext
https://en.cppreference.com/w/cpp/language/move_assignment
|
|
https://docs.microsoft.com/en-us/cpp/cpp/move-constructors-and-move-assignment-operators-cpp
|
|
|
|
2022
|
|
CppCon - Fertig - Back to Basics: C++ Move Semantics 0:00 of 1:02:05
|
|
https://www.youtube.com/watch?v=knEaMpytRMA
|
|
CppCon - Iglberger - Back to Basics: Cpp Value Semantics 0:00 of 48:27
|
|
https://www.youtube.com/watch?v=G9MxNwUoSt0
|
|
https://itnext.io/move-semantics-and-rvalue-references-modern-c-fundamentals-cbbe38760c05
|
|
FPMI - Ibragimov - Cpp and Algorithms
|
|
https://www.youtube.com/playlist?list=PL4_hYwCyhAvY1CNC2azvnDjkQfx5_S13l
|
|
! last videos of course
|
|
2021
|
|
https://proglib.io/p/osnovy-move-semantics-v-c-2021-09-21
|
|
!!! tons of cppreference links
|
|
Josuttis - Modern Cpp - Move Semantics
|
|
https://www.youtube.com/watch?v=YcZJsVPqOdc
|
|
https://artificial-mind.net/blog/2021/10/23/return-moves
|
|
https://www.thecodedmessage.com/posts/cpp-move/
|
|
https://radekvit.medium.com/move-semantics-in-c-and-rust-the-case-for-destructive-moves-d816891c354b
|
|
2020
|
|
CppCon - Josuttis - The Hidden Secrets of Move Semantics 0:00 of 1:05:29
|
|
https://www.youtube.com/watch?v=TFMKjL38xAI
|
|
https://herbsutter.com/2020/02/17/move-simply/
|
|
https://habr.com/ru/post/484380/
|
|
2019
|
|
https://www.bfilipek.com/2019/07/move-debug.html
|
|
https://medium.com/@winwardo/c-moves-for-people-who-dont-know-or-care-what-rvalues-are-%EF%B8%8F-56ee122dda7
|
|
2018
|
|
O'Dwyer - Trivially Relocatable
|
|
https://www.youtube.com/watch?v=xxta6LEn9Hk
|
|
https://p1144.godbolt.org/z/Qvyuvr
|
|
O'Dwyer - Return Value Optimization: Harder Than It Looks
|
|
https://www.youtube.com/watch?v=hA1WNtNyNbo
|
|
https://www.fluentcpp.com/2018/12/11/overview-of-std-map-insertion-emplacement-methods-in-cpp17/
|
|
https://blogs.msdn.microsoft.com/vcblog/2018/12/10/guaranteed-copy-elision-does-not-elide-copies/
|
|
Aloni - Rust - System Programming Language
|
|
http://blog.aloni.org/rust-featurewise-slides-1/#/front-page
|
|
https://www.fluentcpp.com/2018/07/17/how-to-construct-c-objects-without-making-copies/
|
|
|
|
From Meyers:
|
|
std::move is an unconditional cast to r-val
|
|
the better name for std::move will be rvalue_cast
|
|
std::move turns its arg to rval even if it isn't, and achieves that by "hiding the name"
|
|
|
|
std::forward ... conditional ...
|
|
casts param to rval iff rval was passed in
|
|
|
|
// conceptual impl at namespace std
|
|
|
|
template<typename T>
|
|
T &&forward(T &¶m)
|
|
{
|
|
if (is_lvalue_reference<T>::value)
|
|
return param
|
|
else
|
|
return move(param); // cast to rval
|
|
}
|
|
|
|
Universal ref - can become either lval or rval
|
|
|
|
decltype(auto) - for return type
|
|
|
|
Ex 1:
|
|
|
|
class string {
|
|
public:
|
|
...
|
|
string &operator=(const string &rhs); // copy assignment
|
|
string &operator=(string &&rhs); // move assignment
|
|
...
|
|
};
|
|
|
|
void processAndAdd(const string s)
|
|
{
|
|
...
|
|
sds.name = std::move(s); // copies s! since s is declared as const
|
|
...
|
|
}
|
|
|
|
Ex 2:
|
|
|
|
void process(Widget &lvalParam);
|
|
void process(Widget &&rvalParam);
|
|
|
|
template<typename T>
|
|
void logAndProcess(T &¶m)
|
|
{
|
|
...
|
|
process(std::forward<T>(param));
|
|
}
|
|
|
|
Widget w;
|
|
logAndProcess(w); // call with lval
|
|
logAndProcess(std::move(w)); // call with rval
|
|
|
|
|
|
From Lavavej:
|
|
don't return by &&
|
|
don't return by const &
|
|
(NOTE: RVO, NRVO optimizations do the job)
|
|
|
|
|
|
From ... Becker:
|
|
|
|
Derived(Derived &&rhs)
|
|
: Base (std::move(rhs)) // !!! very important to cast to rval here, maybe using std::forward
|
|
{
|
|
// other stuff
|
|
}
|
|
|
|
RVO (return value optimization)
|
|
|
|
X foo()
|
|
{
|
|
X x;
|
|
// ...
|
|
return x; // !!! don't need to call std::move since compiler does RVO and would construct X object directly at the location of foo's return value
|
|
}
|
|
|
|
Ex 3. We use URef when there is a type-deduction, if there is no - we just about RRef
|
|
|
|
void std::vector<Widget>::push_back(Widget &&x); // no type-deduction needed, so - RRef
|
|
|
|
template<class ...Args>
|
|
void std::vector<Widget>::emplace_back(Args &&... args); // type-deduction, so - URef
|
|
|
|
Ex 4.
|
|
|
|
Reference collapsing is used for:
|
|
- template arg deduction
|
|
- auto-vars
|
|
- decltypes
|
|
|
|
Ex 5.
|
|
http://candcplusplus.com/c-difference-between-emplace_back-and-push_back-function/
|
|
|
|
template<class... Args>
|
|
void emplace_back(Args &&... args);
|
|
|
|
Appends a new element to the end of the container. The element is constructed in-place, i.e. no copy or move operations are performed.
|
|
|
|
vector samples
|
|
https://pagefault.blog/2018/03/01/common-misconception-with-cpp-move-semantics/
|
|
https://habr.com/ru/post/174019/
|