Difference between revisions of "cpp/thread/yield"
From cppreference.com
m (Use since= and until= params of {{ddcl}} template.) |
(behavioral notes) |
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===Return value=== | ===Return value=== | ||
(none) | (none) | ||
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| + | ===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=== | ||
Revision as of 16:39, 20 December 2013
| Defined in header <thread>
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| void yield(); |
(since C++11) | |
Provides a hint to the implementation to reschedule the execution of threads, allowing other threads to run.
Contents |
Parameters
(none)
Return value
(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 (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).
Example
Run this code
#include <iostream> #include <chrono> #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
