constexpr defer_lock_t defer_lock {};
Defer lock
Value used as possible argument to unique_lock's constructor.

unique_lock objects constructed with defer_lock do not lock the mutex object automatically on construction, initializing them as not owning a lock.

The value is a compile-time constant that carries no state, and is merely used to disambiguate between constructor signatures.

defer_lock_t is an empty class.

See also