标准预定义了哪些用户定义的文字? [英] Which user-defined-literals are predefined by the standard?

问题描述

我的问题听起来像是一个矛盾，但是除了 user-defined-literal .我不知道该如何引用新的文字语法.

My question sounds like a contradiction, but I don't know how else to refer to the new literal syntax other than user-defined-literal.

std::string operator "" s ( const char* str, size_t len )
{
   return std::string( str, len );
}

assert( "foo"s == "bar"s );

我记得听到用户定义的文字应该以 _ 前缀开头.这意味着该库为我们定义了一些非前缀的文字.

I remember hearing that user defined literals should start with an _ prefix. That would imply that the library defines some non-prefixed literals for us.

标准是否在标准库中提供一些UDL?
如果是，那是什么?

Does the standard provide some UDLs in the the standard library?
If yes, what are they?

推荐答案

该语言已使用常规文字后缀，例如 1U .

The language already use regular literals suffixes, for example 1U.

如果您将 U 用作用户定义的文字，那么建议将变得模棱两可.

It would become ambiguous if you were to use U as a user-defined-literal, thus the recommendation.

整数后缀: u ， U ， l ， L ， ll ， LL

浮动后缀: f ， F ， l ， L

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