未知的元字符在C / C ++字符串字面量？ [英] Unknown meta-character in C/C++ string literal?

问题描述

我创建了以下code段一个新项目：

I created a new project with the following code segment:

char* strange = "(Strange??)";
cout << strange << endl;

导致下面的输出

resulting in the following output:

（奇怪]

因此​​翻译'？） - >]

Thus translating '??)' -> ']'

调试它表明我的char *字符串文字实际上是一个价值，它是不是甲流的翻译。这显然​​不是我见过的元字符序列。
某种统一的code或者宽字符序列？我不这么认为......但是我已经试过禁用所有相关的项目设置，也没有用。

Debugging it shows that my char* string literal is actually that value and it's not a stream translation. This is obviously not a meta-character sequence I've ever seen. Some sort of Unicode or wide char sequence perhaps? I don't think so however... I've tried disabling all related project settings to no avail.

任何人有一个解释？

• 搜索：'问号，问号，右括号'C C ++字符串字面量

推荐答案

你看到的被称为 三字符的。

What you're seeing is called a trigraph.

在用大人的书面语言，一是问号足以满足任何情况。不要使用一个以上的时间和你永远不会再看到这一点。

In written language by grown-ups, one question mark is sufficient for any situation. Don't use more than one at a time and you'll never see this again.

GCC忽略默认情况下，三字母，因为几乎没有人使用它们故意。与 -trigraph 选项启用它们，或者告诉编译器与 -Wtrigraphs 选项警告你他们。

GCC ignores trigraphs by default because hardly anyone uses them intentionally. Enable them with the -trigraph option, or tell the compiler to warning you about them with the -Wtrigraphs option.

的Visual C ++ 2010也默认和报价 / ZC禁止它们：三字母启用它们。我不能找到方法来启用或以前版本中禁用他们什么。

Visual C++ 2010 also disables them by default and offers /Zc:trigraphs to enable them. I can't find anything about ways to enable or disable them in prior versions.

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