© 2023 Bloomberg Finance L.P. All rights reserved. Exceptionally Bad: The story on the misuse of exceptions and how to do better Core C++ June 7, 2023 Pete Muldoon Senior Engineering Lead© 2023 Bloomberg Bloomberg Finance L.P. All rights reserved. Exceptionally Bad: The story on the misuse of exceptions and how to do better Core C++ June 7, 2023 Pete Muldoon Senior Engineering Lead Exceptions in C++ work • Local error handling • Used for erase/mitigate/recover from the exception • Probably a misuse of exceptions • However the thrower does not know return depth as it’s a hidden relationship • Imposed

Maintenance overhead Add public accessor to widget being tested Testing easier Maybe encourages misuse of library if internals exposed42 High level view – version 2 Implementation Tests class GoToLineTool Maintenance overhead Add public accessor to widget being tested Testing easier Maybe encourages misuse of library if internals exposed49 Testing Custom Qt Widgets – part 2 Option Advantages Disadvantages Maintenance overhead Add public accessor to widget being tested Testing easier Maybe encourages misuse of library if internals exposed Add protected accessor … Make the test fixture inherit the widget

STUDY: LOGGING CASE STUDY: LOGGING From "Easy to Use, Hard to Misuse: Declarative Style in C++" (CppCon 2018) From "Easy to Use, Hard to Misuse: Declarative Style in C++" (CppCon 2018) The The bool bool

not char* 1 47compile-time format strings improved api runtime format api had only vformat easy to misuse api paper addresses this case in working dra� P2918 Runtime format strings II //before std::string , 42); 5 48compile-time format strings improved api runtime format api had only vformat easy to misuse api paper addresses this case in working dra� P2918 Runtime format strings II //before std::string

zumero_register() returns SQLITE_MISUSE? Zumero requires SQLite version 3.7.11 or higher. If the Zumero library is linked with an older version of SQLite, zumero_register() returns SQLITE_MISUSE. Can I use SQLite's

unintended behavior (e.g. broken connection), but still a worthy tradeoff, especially in preventing misuse More on RedBPF • Plan to make RedBPF support more (all) program types - make it a generic compiler

What happens if I call Register twice? –Josh Bloch “APIs should be easy to use and hard to misuse.” If you think it’s slow, prove it with a benchmark Going beyond “You type g o, a space, and

paid contributors! Tokio is good enough Tokio Tokio's APIs are memory-safe, thread-safe, and misuse-resistant. This helps prevent common bugs, such as unbounded queues, buffer overflows, and task

implement procedures to protect keys used to secure stored cardholder data against disclosure and misuse. 3.6 Fully document and implement all key-management processes and procedures for cryptographic

attributes you find. ● Pay attention to the API - the abstraction layer ○ Easy to use, hard to misuse (Ben Deane) ○ Consider preconditions and postconditions ○ Return every potentially useful piece