operator<<(std::thread::id)

 

C++

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Freestanding and hosted

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Feature test macros (C++20)

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Concepts library (C++20)

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Ranges library (C++20)

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Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Concurrency support library

Threads thread (C++11) jthread (C++20) 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) Cooperative cancellation stop_token (C++20) inplace_stop_token (C++26) never_stop_token (C++26) stop_source (C++20) inplace_stop_source (C++26)   stop_callback (C++20) inplace_stop_callback (C++26) stop_callback_for_t (C++26) stoppable_token (C++26) unstoppable_token (C++26) stoppable-source (C++26) stoppable-callback-for (C++26)   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 (C++11) lock_guard (C++11) scoped_lock (C++17) unique_lock (C++11) shared_lock (C++14) once_flag (C++11) call_once (C++11) try_lock (C++11) defer_locktry_to_lockadopt_lockdefer_lock_ttry_to_lock_tadopt_lock_t (C++11)(C++11)(C++11)(C++11)(C++11)(C++11) Condition variables condition_variable (C++11) condition_variable_any (C++11) notify_all_at_thread_exit (C++11) cv_status (C++11) Semaphores counting_semaphorebinary_semaphore (C++20)(C++20) Latches and Barriers latch (C++20) barrier (C++20) 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) Safe Reclamation rcu_obj_base (C++26) rcu_domain (C++26) rcu_default_domain (C++26) rcu_synchronize (C++26) rcu_barrier (C++26) rcu_retire (C++26) Hazard Pointers hazard_pointer_obj_base (C++26) hazard_pointer (C++26) make_hazard_pointer (C++26)

Atomic types atomic (C++11) atomic_ref (C++20) atomic_flag (C++11) Initialization of atomic types atomic_init (C++11)(deprecated in C++20) ATOMIC_VAR_INIT (C++11)(deprecated in C++20) ATOMIC_FLAG_INIT (C++11) Memory ordering memory_order (C++11) kill_dependency (C++11) atomic_thread_fence (C++11) atomic_signal_fence (C++11) Free functions for atomic operations atomic_storeatomic_store_explicit (C++11)(C++11) atomic_loadatomic_load_explicit (C++11)(C++11) atomic_exchangeatomic_exchange_explicit (C++11)(C++11) atomic_compare_exchange_weakatomic_compare_exchange_weak_explicitatomic_compare_exchange_strongatomic_compare_exchange_strong_explicit (C++11)(C++11)(C++11)(C++11) atomic_fetch_addatomic_fetch_add_explicit (C++11)(C++11) atomic_fetch_subatomic_fetch_sub_explicit (C++11)(C++11) atomic_fetch_andatomic_fetch_and_explicit (C++11)(C++11) atomic_fetch_oratomic_fetch_or_explicit (C++11)(C++11) atomic_fetch_xoratomic_fetch_xor_explicit (C++11)(C++11) atomic_fetch_maxatomic_fetch_max_explicit (C++26)(C++26) atomic_fetch_minatomic_fetch_min_explicit (C++26)(C++26) atomic_is_lock_free (C++11) atomic_waitatomic_wait_explicit (C++20)(C++20) atomic_notify_one (C++20) atomic_notify_all (C++20) Free functions for atomic flags atomic_flag_test_and_setatomic_flag_test_and_set_explicit (C++11)(C++11) atomic_flag_clearatomic_flag_clear_explicit (C++11)(C++11) atomic_flag_testatomic_flag_test_explicit (C++20)(C++20) atomic_flag_waitatomic_flag_wait_explicit (C++20)(C++20) atomic_flag_notify_one (C++20) atomic_flag_notify_all (C++20)

 

std::thread

Member classes

thread::id

Member functions

thread::thread

thread::~thread

thread::operator=

Observers

thread::joinable

thread::get_id

thread::native_handle

thread::hardware_concurrency

Operations

thread::join

thread::detach

thread::swap

Non-member functions

swap(std::thread) (C++11)

 

std::thread::id

Member functions

id::id

Non-member functions

operator==operator!=operator<operator<=operator>operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

operator<<

Helper classes

hash<std::thread::id>

formatter<std::thread::id> (C++23)

 

Defined in header <thread>
template< class CharT, class Traits > std::basic_ostream<CharT,Traits>&     operator<<( std::basic_ostream<CharT,Traits>& ost, std::thread::id id );		(since C++11)

Writes a textual representation of a thread identifier id to the output stream ost.

If two thread identifiers compare equal, they have identical textual representations; if they do not compare equal, their representations are distinct.

Parameters

ost	-	output stream to insert the data into
id	-	thread identifier

Return value

ost

Exceptions

May throw implementation-defined exceptions.

Example

Run this code

#include <chrono>
#include <iostream>
#include <thread>
using namespace std::chrono;
 
int main()
{
    std::thread t1([]{ std::this_thread::sleep_for(256ms); });
    std::thread t2([]{ std::this_thread::sleep_for(512ms); });
 
    std::clog << t1.get_id() << '\n' << t2.get_id() << '\n';
 
    t1.join();
    t2.join();
}

Possible output:

141592653589793
141421356237309