小编mar*_*rkd的帖子

在g ++ 4.7和g ++ 4.8.2下使用零初始化原子编译下面需要数小时.默认初始化的原子和零初始化的非原子编译立即.

#include <iostream>
#include <array>
#include <algorithm>
#include <atomic>

int main(int argc, char* argv[]) {

    //std::array<std::atomic<int>, 1000000>  arr;         // default initialization (i.e., random data) = FAST

    //std::array<int, 1000000>  arr={{}};     // zero init non-atomic = FAST

    //std::array<std::atomic<int>, 1000000>  arr{{}};   // zero initialization = FOREVER

    //std::array<std::atomic<int>, 1000000>  arr={{}};     // zero init via assignment = FOREVER

    std::array<std::atomic<int>, 1000000>  arr{};   // zero initialization = FOREVER

    std::cerr << "sum = " << std::accumulate(arr.begin(), arr.end(), 0) << std::endl;
}

g++ -std=c++11 array.cpp …