1 獲取CPU核心數量
使用std::thread::hardware_concurrency()獲取當前CPU核心數量。
代碼示例:
#include <iostream>
#include <thread>
int main()
{
std::cout << std::thread::hardware_concurrency() << std::endl;
getchar();
return 0;
}
2 獲取當前線程ID
get_id()可用於獲取當前線程的id。
代碼示例:
#include <iostream>
#include <thread>
int main()
{
std::thread thread{ [] {std::cout << "線程函數被啓動" << std::endl; } };
std::cout << thread.get_id() << std::endl;
thread.join();
getchar();
return 0;
}
3 線程休眠
3.1 sleep_for讓當前線程休眠一段時間
#include <iostream>
#include <thread>
int main()
{
std::thread thread{ [] {std::cout << "線程函數被啓動" << std::endl; } };
std::this_thread::sleep_for(std::chrono::seconds(1));
std::cout << thread.get_id() << std::endl;
thread.join();
getchar();
return 0;
}
3.2 sleep_until讓當前線程休眠一直到指定時間
#include <iostream>
#include <iomanip>
#include <thread>
#include <chrono>
#include <ctime>
#pragma warning(disable:4996)//加上可去掉unsafe 請使用localtime_s的編譯報錯
int main()
{
std::thread thread{ [] {std::cout << "線程函數被啓動" << std::endl; } };
std::time_t tt = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
struct std::tm * ptm = std::localtime(&tt);
std::cout << "當前時間爲: " << std::put_time(ptm, "%X") << std::endl;
// 設定線程被喚醒時間爲1分鐘後
ptm->tm_min += 1;
std::this_thread::sleep_until(std::chrono::system_clock::from_time_t(mktime(ptm)));
std::cout << thread.get_id() << std::endl;
std::cout << "線程重新被喚起時間爲:" << std::put_time(ptm, "%X") << std::endl;;
thread.join();
getchar();
return 0;
}
4 yield
yield放棄當前線程執行,回到準備狀態,重新分配cpu資源。所以調用該方法後,可能執行其他線程,也可能還是執行該線程。
#include <iostream>
#include <thread>
#include <chrono>
int main()
{
bool ready = false;
std::thread thread{ [&] {
while (!ready)
{
std::cout << "線程函數被掛起" << std::endl;
std::this_thread::yield();
ready = true;
}
std::cout << "線程函數被啓動" << std::endl;
} };
thread.join();
getchar();
return 0;
}
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