C++11:std::locale::empty() 是一个东西吗？

Question

正在尝试编译 some code来自 StackOverflow，基本上，这些行:

std::wifstream wif(filename);
wif.imbue(std::locale(std::locale::empty(), new std::codecvt_utf8<wchar_t>));

GCC 版本:gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0

编译错误:

'empty' is not a member of 'std::locale'

我同意编译器，并检查了像 cppreference 这样的文档- 没有关于此类事情的信息。头文件也不显示任何内容。

我想知道，这是我个人还是其他主题的示例代码...

它可以是 MSVC 功能吗？ (我使用的示例代码来自与Windows相关的问题)

Answer 1

这是语言环境类的特定于平台的扩展，它曾经在 this MSVC documentation 中描述过*:

In this implementation, you can also call the static member function:

static locale empty( );

to construct a locale object that has no facets. It is also a transparent locale; if the template functions has_facet and use_facet cannot find the requested facet in a transparent locale, they consult first the global locale and then, if that is transparent, the classic locale.

* MSVC 文档链接现已过时，最佳替代品请参见 this documentation page相反