std::unique_lock::try_lock

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

Thread support library

Threads
thread (C++11)
hardware_destructive_interference_sizehardware_constructive_interference_size (C++17)(C++17)
this_thread namespace
get_id (C++11) yield (C++11)	sleep_for (C++11) sleep_until (C++11)
Mutual exclusion
mutex (C++11) recursive_mutex (C++11) shared_mutex (C++17)	timed_mutex (C++11) recursive_timed_mutex (C++11) shared_timed_mutex (C++14)
Generic lock management
lock_guard (C++11) scoped_lock (C++17) unique_lock (C++11) shared_lock (C++14) defer_lock_ttry_to_lock_tadopt_lock_t (C++11)(C++11)(C++11)	lock (C++11) try_lock (C++11) defer_locktry_to_lockadopt_lock (C++11)(C++11)(C++11) once_flag (C++11) call_once (C++11)
Condition variables
condition_variable (C++11)
condition_variable_any (C++11)
notify_all_at_thread_exit (C++11)
cv_status (C++11)
Futures
promise (C++11) future (C++11) shared_future (C++11) packaged_task (C++11) async (C++11)	launch (C++11) future_status (C++11) future_error (C++11) future_category (C++11) future_errc (C++11)

std::unique_lock

Member functions

unique_lock::unique_lock

unique_lock::~unique_lock

unique_lock::operator=

Locking

unique_lock::lock

unique_lock::try_lock

unique_lock::try_lock_for

unique_lock::try_lock_until

unique_lock::unlock

Modifiers

unique_lock::swap

unique_lock::release

Observers

unique_lock::mutex

unique_lock::owns_lock

unique_lock::operator bool

Non-member functions

std::swap

bool try_lock();		(since C++11)

Tries to lock the associated mutex without blocking. Effectively calls mutex()->try_lock().

std::system_error is thrown if there is no associated mutex or if the mutex is already locked by this std::unique_lock.

Parameters

(none)

Return value

true if the ownership of the mutex has been acquired successfully, false otherwise.

Exceptions

• Any exceptions thrown by mutex()->try_lock() (Mutex types do not throw in try_lock, but a custom Lockable might)

• If there is no associated mutex, std::system_error with an error code of std::errc::operation_not_permitted

• If the mutex is already locked by this std::unique_lock, std::system_error with an error code of std::errc::resource_deadlock_would_occur

See also

lock	locks the associated mutex (public member function)
try_lock_for	attempts to lock the associated TimedLockable mutex, returns if the mutex has been unavailable for the specified time duration (public member function)
try_lock_until	tries to lock the associated TimedLockable mutex, returns if the mutex has been unavailable until specified time point has been reached (public member function)
unlock	unlocks the associated mutex (public member function)