Return Value Optimization: Harder Than It Looks
summary
Explains where the return slot lives in typical calling conventions, why C++03/C++11/C++17 rules sometimes elide, sometimes move, and sometimes silently copy; shows surprising failures: slicing and base-class converting constructors block the implicit move, conversion operators and by-value sinks cause copies, rvalue-reference parameters behave differently; implements a Clang diagnostic (-Wreturn-std-move) that detects problematic return x cases and suggests fixes.
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chapters (11)
- 0:00Introduction
- 0:45The Return Slot
- 1:50Big Objects
- 3:08Moving Objects
- 4:45Copy Elision
- 6:34durian
- 7:42RPO rules
- 9:43Example
- 12:28The real deal
- 16:25Why converting constructors
- 18:29Examples
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