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std::jthread

From cppreference.com
< cpp‎ | thread
 
 
Thread support library
Threads
(C++11)
jthread
(C++20)
(C++20)
this_thread namespace
(C++11)
(C++11)
(C++11)
Mutual exclusion
(C++11)
Generic lock management
(C++11)
(C++11)
(C++11)
(C++11)(C++11)(C++11)
(C++11)
(C++11)
Condition variables
(C++11)
Semaphores
Latches and barriers
(C++20)
(C++20)
Futures
(C++11)
(C++11)
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Defined in header <thread>
class jthread;
(since C++20)

The class jthread represents a single thread of execution. It has the same general behavior as std::thread, except that jthread automatically rejoins on destruction, and can be cancelled/stopped in certain situations.

Threads begin execution immediately upon construction of the associated thread object (pending any OS scheduling delays), starting at the top-level function provided as a constructor argument. The return value of the top-level function is ignored and if it terminates by throwing an exception, std::terminate is called. The top-level function may communicate its return value or an exception to the caller via std::promise or by modifying shared variables (which may require synchronization, see std::mutex and std::atomic)

Unlike std::thread, the jthread logically holds an internal private member of type std::stop_source, which maintains shared stop-state. The jthread constructor accepts a function that takes a std::stop_token as its first argument, which will be passed in by the jthread from its internal stop_source. This allows the function to check if stop has been requested during its execution, and return if it has.

std::jthread objects may also be in the state that does not represent any thread (after default construction, move from, detach, or join), and a thread of execution may be not associated with any jthread objects (after detach).

No two std::jthread objects may represent the same thread of execution; std::jthread is not CopyConstructible or CopyAssignable, although it is MoveConstructible and MoveAssignable.

Contents

[edit] Member types

Member type Definition
id std::thread::id
native_handle_type(optional) std::thread::native_handle_type

[edit] Member functions

constructs new jthread object
(public member function) [edit]
if joinable() is true, calls request_stop() and then join(); in either case destructs the jthread object.
(public member function) [edit]
moves the jthread object
(public member function) [edit]
Observers
checks whether the thread is joinable, i.e. potentially running in parallel context
(public member function) [edit]
returns the id of the thread
(public member function) [edit]
returns the underlying implementation-defined thread handle
(public member function) [edit]
returns the number of concurrent threads supported by the implementation
(public static member function) [edit]
Operations
waits for a thread to finish its execution
(public member function) [edit]
permits the thread to execute independently from the thread handle
(public member function) [edit]
swaps two jthread objects
(public member function) [edit]
Stop token handling
returns a stop_source object associated with the shared stop state of the thread
(public member function) [edit]
returns a stop_token associated with the shared stop state of the thread
(public member function) [edit]
requests execution stop via the shared stop state of the thread
(public member function) [edit]

[edit] Non-member functions

specializes the std::swap algorithm
(function) [edit]