Arno Schoedl

The C++ rvalue lifetime disaster

Why do common C++ features like `std::min` and the ternary operator create dangling references? This talk reveals a fundamental language flaw and how to fix it.

The C++ rvalue lifetime disaster
#1about 3 minutes

The dual role of rvalue references in C++

Rvalue references were introduced for move semantics to avoid copies but are also used to manage the lifetime of temporary objects.

#2about 6 minutes

Why temporary lifetime extension fails in modern C++

The pre-C++11 feature for extending temporary object lifetimes does not work correctly with rvalue references, necessitating a custom macro to create a value or reference based on expression type.

#3about 6 minutes

How accessor methods cause rvalue amnesia

Standard accessor methods returning a const lvalue reference incorrectly bind to rvalues, losing critical lifetime information and leading to dangling references.

#4about 4 minutes

A proposal for fixing C++ reference binding rules

A proposed language fix using pragmas would introduce new, safer reference binding rules to prevent short-lived rvalues from binding to long-lived lvalue references.

#5about 3 minutes

Practical mitigations for rvalue lifetime issues today

Use custom macros to manage variable lifetimes, guard member accessors, and implement a correct ternary operator to work around the language's flawed binding rules.

#6about 1 minute

Managing C++ complexity with strong coding guidelines

The best way to manage the growing complexity of C++ is to establish strong internal coding guidelines and use custom libraries to standardize code patterns.

Related jobs
Jobs that call for the skills explored in this talk.

Remote

Name of

Name of

Remote
Intermediate
PHP
Java
+1

Matching moments

Understanding temporary objects and lifetime extension rules
05:02 MIN

Understanding temporary objects and lifetime extension rules

An (In-)Complete Guide to C++ Object Lifetimes

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.
Modern C++ evolution and the burden of backward compatibility
07:52 MIN

Modern C++ evolution and the burden of backward compatibility

Eternal Sunshine of the Spotless Programming Language

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.
Using modern language features for safer code
07:50 MIN

Using modern language features for safer code

C++ in constrained environments

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.
Implicit destruction and best practices for object lifetime
01:58 MIN

Implicit destruction and best practices for object lifetime

An (In-)Complete Guide to C++ Object Lifetimes

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.
C++ availability, ecosystem, and backwards compatibility
06:50 MIN

C++ availability, ecosystem, and backwards compatibility

101 brilliant things of C++

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.
Defining objects and lifetimes in C++
03:06 MIN

Defining objects and lifetimes in C++

An (In-)Complete Guide to C++ Object Lifetimes

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.
Q&A on language design, Rust, and the future of C++
08:47 MIN

Q&A on language design, Rust, and the future of C++

The Design and Evolution of C++

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.
Reviewing common memory safety problems in other languages
05:58 MIN

Reviewing common memory safety problems in other languages

A Love Letter to Rust

Unlock Moments
Create a free account to watch a limited number of Moments each month.
Upgrade to PRO for unlimited access to the full archive.

Featured Partners

Related Videos

See all videos
An (In-)Complete Guide to C++ Object Lifetimes28:07

An (In-)Complete Guide to C++ Object Lifetimes

Jonathan Müller

C++ Features You Might Not Know24:13

C++ Features You Might Not Know

Jonathan Müller

C++ in constrained environments1:00:16

C++ in constrained environments

Bjarne Stroustrup

101 brilliant things of C++45:27

101 brilliant things of C++

Andreas Fertig

The Design and Evolution of C++1:01:15

The Design and Evolution of C++

Bjarne Stroustrup

Why Iterators Got It All Wrong — and what we should use instead26:12

Why Iterators Got It All Wrong — and what we should use instead

Arno Schödl

Guided Memory Management: Rust's Ownership Model00:18

Guided Memory Management: Rust's Ownership Model

Stefan Baumgartner

A Love Letter to Rust50:43

A Love Letter to Rust

Rainer Stropek

Related Articles

View all articles
CH
Chris Heilmann
All the videos of Halfstack London 2024!
Last month was Halfstack London, a conference about the web, JavaScript and half a dozen other things. We were there to deliver a talk, but also to record all the sessions and we're happy to share them with you. It took a bit as we had to wait for th...
All the videos of Halfstack London 2024!

From learning to earning

Jobs that call for the skills explored in this talk.