Parallelism Guidelines

Deadlock guidelines

• CP.20: Use RAII, never plain lock()/unlock()
• CP.21: Use std::lock() or std::scoped_lock to acquire multiple mutexes
• CP.22: Never call unknown code while holding a lock (e.g., a callback)
• [CP.50: Define a mutex together with the data it guards. Use synchronized_value where possible](https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rconc-mutex)
• CP.52: Do not hold locks or other synchronization primitives across suspension points

Lifetime guidelines

• CP.23: Think of a joining thread as a scoped container
• CP.25: Prefer gsl::joining_thread over std::thread
• CP.26: Don’t detach() a thread

New guidelines

• 0.4.8 Mutexes locked with std::lock or std::try_lock shall be wrapped with std::lock_guard, std::unique_lock or std::shared_lock with adopt_lock tag within the same scope.
  • CP.44: Remember to name your lock_guards and unique_locks
• 0.4.13 std::recursive_mutex and std::recursive_timed_mutex should not be used
  • CP.22: Never call unknown code while holding a lock (e.g., a callback)
• 0.5.4 Do not use std::condition_variable_any on std::mutex
• 0.6.1 Use only std::memory_order_seq_cst for atomic operations
• 0.12.4 Always explicitly specify a launch policyfor std::async
• 0.12.11 Objects of type std::mutex shall not have dynamic storage duration

Modfied guidelines

• 0.10.5 Use std::call_once to ensure a function is called exactly once (rather than the Double-Checked Locking pattern)
  • CP.110: Do not write your own double-checked locking for initialization

MISRA exclusive rules

• 0.4.4 Do not destroy objects of the following types std::mutex , std::timed_mutex , std::recursive_mutex , std::recursive_timed_mutex , std::shared_mutex , std::shared_timed_mutex if object is in locked or shared locked state
• 0.4.11 There shall be no code path which results in locking of the non-recursive mutex within the scope when this mutex is already locked
• 0.4.12 The order of nested locks unlock shall form a directed acyclic graph

Reference

• Parallelism Safety-Critical Guidelines for C++ - Michael Wong, Andreas Weis, Ilya Burylov - CppCon22
• C++ Core Guidelines
• CP: Concurrency and parallelism