|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
TheSharedLockable requirements describe the minimal characteristics of types that provide shared blocking semantics for execution agents (i.e. threads).
Contents |
For typeL to beSharedLockable, the following conditions have to be satisfied for an objectm of typeL:
| Expression | Preconditions | Effects | Return value |
|---|---|---|---|
| m.lock_shared() | Blocks until a lock can be obtained for the current execution agent (thread, process, task). If an exception is thrown, no lock is obtained. | ||
| m.try_lock_shared() | Attempts to obtain a lock for the current execution agent (thread, process, task) without blocking. If an exception is thrown, no lock is obtained. | true if the lock was obtained,false otherwise | |
| m.unlock_shared() | The current execution agent holds a shared lock onm. | Releases the shared lock held by the execution agent. Throws no exceptions. |
A lock on an object is said to beshared lock if it is acquired by a call tolock_shared,try_lock_shared,try_lock_shared_for, ortry_lock_shared_until member function.
The following standard library types satisfySharedLockable requirements:
(C++17) | provides shared mutual exclusion facility (class)[edit] |
(C++14) | provides shared mutual exclusion facility and implements locking with a timeout (class)[edit] |
