std可选:无此类文件或目录 [英] std optional: No such file or directory
问题描述
我尝试使用不同的编译器(包括gcc 6.1)编译以下程序:
I tried to compile the following program with different compilers (including gcc 6.1) :
#include <optional>
int main()
{
std::optional<int> o1;
}
输出为
main.cpp:1:20:致命错误:可选:没有这样的文件或目录#include可选
main.cpp:1:20: fatal error: optional: No such file or directory #include optional
对于此处给出的示例,这甚至是正确的: http://en.cppreference.com/w/cpp/utility/optional/optional
This is even true for the examples given here: http://en.cppreference.com/w/cpp/utility/optional/optional
任何线索为何?
推荐答案
std::optional
将成为C ++ 17标准的一部分,但如果要在此之前使用,则必须使用std::experimental::optional
代替在标题<experimental/optional>
中.
std::optional
will be part of the C++17 standard, but if you want to use before then you will have to use std::experimental::optional
instead, available in the header <experimental/optional>
.
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