Difference between revisions of "cpp/thread/yield"
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{{cpp/title|n=this_thread::|yield}} | {{cpp/title|n=this_thread::|yield}} | ||
{{cpp/thread/navbar}} | {{cpp/thread/navbar}} | ||
| − | {{ddcl | header=thread | since=c++11 | 1= | + | {{ddcl|header=thread|since=c++11|1= |
| − | void yield(); | + | void yield() noexcept; |
}} | }} | ||
| Line 12: | Line 12: | ||
===Return value=== | ===Return value=== | ||
(none) | (none) | ||
| + | |||
| + | ===Notes=== | ||
| + | The exact behavior of this function depends on the implementation, in particular on the mechanics of the OS scheduler in use and the state of the system. For example, a first-in-first-out realtime scheduler ({{tt|SCHED_FIFO}} in Linux) would suspend the current thread and put it on the back of the queue of the same-priority threads that are ready to run, and if there are no other threads at the same priority, {{tt|yield}} has no effect. | ||
===Example=== | ===Example=== | ||
| − | {{example | + | {{example |
| − | + | |code= | |
| − | + | ||
| − | + | ||
#include <chrono> | #include <chrono> | ||
| + | #include <iostream> | ||
#include <thread> | #include <thread> | ||
| Line 27: | Line 29: | ||
auto start = std::chrono::high_resolution_clock::now(); | auto start = std::chrono::high_resolution_clock::now(); | ||
auto end = start + us; | auto end = start + us; | ||
| − | do { | + | do |
| + | { | ||
std::this_thread::yield(); | std::this_thread::yield(); | ||
| − | } while (std::chrono::high_resolution_clock::now() < end); | + | } |
| + | while (std::chrono::high_resolution_clock::now() < end); | ||
} | } | ||
| Line 43: | Line 47: | ||
<< " microseconds\n"; | << " microseconds\n"; | ||
} | } | ||
| − | + | |p=true | |
| + | |output= | ||
waited for 128 microseconds | waited for 128 microseconds | ||
}} | }} | ||
| − | + | ===See also=== | |
| − | + | {{dsc begin}} | |
| − | + | {{dsc see c|c/thread/thrd_yield}} | |
| − | + | {{dsc end}} | |
| − | + | ||
| − | + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | |
| − | + | ||
| − | + | ||
Latest revision as of 02:35, 7 October 2024
| Defined in header <thread>
|
||
| void yield() noexcept; |
(since C++11) | |
Provides a hint to the implementation to reschedule the execution of threads, allowing other threads to run.
Contents |
[edit] Parameters
(none)
[edit] Return value
(none)
[edit] Notes
The exact behavior of this function depends on the implementation, in particular on the mechanics of the OS scheduler in use and the state of the system. For example, a first-in-first-out realtime scheduler (SCHED_FIFO in Linux) would suspend the current thread and put it on the back of the queue of the same-priority threads that are ready to run, and if there are no other threads at the same priority, yield has no effect.
[edit] Example
Run this code
#include <chrono> #include <iostream> #include <thread> // "busy sleep" while suggesting that other threads run // for a small amount of time void little_sleep(std::chrono::microseconds us) { auto start = std::chrono::high_resolution_clock::now(); auto end = start + us; do { std::this_thread::yield(); } while (std::chrono::high_resolution_clock::now() < end); } int main() { auto start = std::chrono::high_resolution_clock::now(); little_sleep(std::chrono::microseconds(100)); auto elapsed = std::chrono::high_resolution_clock::now() - start; std::cout << "waited for " << std::chrono::duration_cast<std::chrono::microseconds>(elapsed).count() << " microseconds\n"; }
Possible output:
waited for 128 microseconds
[edit] See also
| C documentation for thrd_yield
|
