c++ - 如何将 std::string 转换为 boost::chrono::nanoseconds

Question

我尝试过从 std::string 和 long long 进行词法转换。两者都给出零值。有什么想法吗？

boost::lexical_cast<boost::chrono::nanoseconds>(value) //value can be of std::string or long long type

Answer 1

首先尝试对字符串使用词法转换以查看预期结果:

#include <iostream>
#include <string>
#include "boost/lexical_cast.hpp"
#include "boost/chrono.hpp"

int main()
{
    boost::chrono::nanoseconds test1{1000}; // could use long long here directly
    auto text = boost::lexical_cast<std::string>(test1);
    std::cout << text << '\n';
    auto val = boost::lexical_cast<boost::chrono::nanoseconds>(text);
    std::cout << val << '\n';
}

打印:

1000 nanoseconds
1000 nanoseconds