All 10 Undefined Behavior questions
More in Undefined Behavior
Why is reading an uninitialized variable undefined behavior? What happens if you dereference a null pointer? What are common causes of undefined behavior? Why is signed integer overflow undefined but unsigned overflow defined? What is the strict aliasing rule and how can violating it cause UB? How can undefined behavior cause 'impossible' optimizations and bugs? What is a data race and why is it undefined behavior?
Advertisement
C++ › Undefined Behavior

How do you detect and prevent undefined behavior?

Intermediate

Answer

Prevent UB with safe practices: initialize variables, use containers/at()/bounds checks, smart pointers and RAII, avoid manual casts, and enable warnings (-Wall -Wextra). Detect it with sanitizers (UndefinedBehaviorSanitizer, AddressSanitizer, ThreadSanitizer), static analysis (clang-tidy, cppcheck), and thorough tests run under these tools in CI.
g++ -fsanitize=undefined,address -g prog.cpp
Real-world example Running tests under UBSan and ASan in CI catches out-of-bounds and overflow bugs before release.

Common follow-ups: What does UBSan detect? | What coding practices prevent UB?

Memory Management Undefined Behavior Undefined Behavior
All 10 Undefined Behavior questions