How deeply does 100 C++ Mistakes and How to Avoid Them cover std::move?

Explains the cast and moved-from state, then demonstrates pointer transfer in move construction and unique_ptr ownership.

Std::move

As explained in 100 C++ Mistakes and How to Avoid Them

std::move is a C++ standard library function template that casts an expression to an rvalue reference to enable move operations.

Mistake: treating std::move as the operation that moves an object. It actually casts an lvalue to an rvalue reference, making the expression eligible for move construction or move assignment instead of ordinary copying. section 2.1 section 2.8

After transfer, treat the source as drained and do not use it unless it is reinitialized. Move constructors and move-assignment operators should neutralize transferred pointers, commonly by setting them to nullptr. section 2.1 section 2.8

Transfer a Page without copying its resources

A copy such as `Page p2 = p1;` duplicates the body and then deletes data from the source in the problematic implementation. The corrected version supplies `Page(Page&& o)`, transfers the pointers, clears `o.headers` and `o.body`, and uses `Page p2 = std::move(p1);`. The transfer can therefore use move semantics rather than a costly copy.

Transfer exclusive ownership with unique_ptr

Use `auto b2 = std::move(b1);` to transfer a `Buffer` held by `std::unique_ptr`. The receiving owner takes the resource, while the original owner should be treated as unusable until reinitialized. section 2.8

How 100 C++ Mistakes and How to Avoid Them covers it

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Also explained in

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C++ Concurrency in Action, Second Edition`std::move` is a C++ standard library function template that casts an expression to an rvalue reference, enabling move operations.
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Learn C++ by Examplestd::move is a C++ standard library utility that casts an expression to an rvalue reference to enable moving from it.

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Related concepts

rvalueproduces · An rvalue is an expression that does not designate an assignable object and provides a value or temporary object for use in computation.
std::threadused by · A C++ standard library class that represents and manages a thread of execution.
unique_lockused by · std::unique_lock is a C++ standard library class template that manages exclusive ownership of a mutex and supports deferred locking, unlocking, and ownership transfer.
std::unique_ptrused by · std::unique_ptr is a C++ standard-library smart pointer that provides exclusive ownership of a dynamically allocated object and manages its lifetime.
moveimplements · Move semantics describe the transfer of a value or its resources to another binding or object rather than duplicating them.

This explainer was generated by Manning's knowledge graph from the text of 100 C++ Mistakes and How to Avoid Them. The section links point to the parts of the book it draws on.