An object is a region of storage with a type and value, and its lifetime is a property on the abstract machine that dictates when it can be safely manipulated.
Objects created by variable definitions have their lifetime influenced by their storage duration (automatic, static, or thread), which is distinct from the object's actual lifetime that begins after initialization.
Temporary objects are created for prvalues and are usually destroyed at the end of an expression, but their lifetime can be extended when bound directly to a reference or used in a range-based for loop.
Placement `new` allows constructing an object in pre-allocated storage, and if the new object is "transparently replaceable," existing pointers and references to the old object remain valid.
When an object replacement is not transparent (e.g., for `const` objects), `std::launder` must be used on old pointers to prevent undefined behavior by forcing the compiler to acknowledge the new object in that storage.
Certain operations like `malloc` can implicitly create objects to make C-style code valid, and `std::start_lifetime_as` should be used to correctly begin the lifetime of an object in a raw byte buffer.
Reusing storage with placement `new` implicitly destroys the previous object, and best practices include explicit object creation and using the newly returned pointer to avoid aliasing issues.
24:17Arno Schoedl
24:13Jonathan Müller
45:27Andreas Fertig
1:01:15Bjarne Stroustrup
1:00:16Bjarne Stroustrup
26:12Arno Schödl
00:18Stefan Baumgartner
25:29Diana Gastrin
Jobs that call for the skills explored in this talk.
Vesterling Consulting GmbH
Vesterling Consulting GmbH