32 Thread support library [thread]

32.2 Requirements [thread.req]

32.2.5 Requirements for Cpp17Lockable types [thread.req.lockable]

32.2.5.2 Cpp17BasicLockable requirements [thread.req.lockable.basic]

A type L meets the Cpp17BasicLockable requirements if the following expressions are well-formed and have the specified semantics (m denotes a value of type L).
m.lock()
Effects: Blocks until a lock can be acquired for the current execution agent.
If an exception is thrown then a lock shall not have been acquired for the current execution agent.
m.unlock()
Requires: The current execution agent shall hold a lock on m.
Effects: Releases a lock on m held by the current execution agent.
Throws: Nothing.