std::move (C++11)

In a Nutshell

It force-casts an lvalue to an rvalue reference, telling the compiler "this object's resources are up for grabs" — which triggers move construction or move assignment and avoids a deep copy.

Header

#include <utility>

Core API Quick Reference

Operation	Signature	Description
Move cast (since C++14)	template<class T> constexpr std::remove_reference_t<T>&& move(T&& t) noexcept;	Converts the object t to an rvalue reference (xvalue)
Perfect forwarding	template<class T> T&& forward(typename std::remove_reference<T>::type& t) noexcept;	Preserves the value category in forwarding-reference scenarios; equivalent to std::move for rvalue arguments and to pass-by-reference for lvalues
Conditional move	template<class T> typename std::conditional<...>::type move_if_noexcept(T& t) noexcept;	Converts to an rvalue if the move constructor is non-throwing; otherwise returns an lvalue

Minimal Example

#include <iostream>
#include <string>
#include <utility>
#include <vector>
// Standard: C++11
int main() {
    std::string str = "Hello";
    std::vector<std::string> v;
    v.push_back(str);              // copy
    v.push_back(std::move(str));   // move; str is left in a valid but unspecified state
    std::cout << v[0] << " " << v[1] << "\n";
    std::cout << "str empty: " << str.empty() << "\n";
}

Embedded Suitability: High

• Zero-overhead abstraction: std::move is essentially a static_cast, done at compile time with no runtime cost
• Avoids deep copies: when passing large buffers (such as std::vector<uint8_t> or std::string), it significantly cuts both RAM usage and CPU overhead
• Pairs with custom resource classes: can be used to transfer ownership of raw pointers (in combination with RAII), replacing manual resource handover
• Note that a moved-from object is in a "valid but unspecified" state: you can no longer read its value — you can only assign to it or destroy it

Compiler Support

GCC	Clang	MSVC
4.6	3.0	19.0

See Also

• cppreference: std::move

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