是否必须逃离制表字符C和C ++？ [英] Is it mandatory to escape tabulator characters in C and C++?

问题描述

在C和C ++（和其他几种语言）的字符和字符串常量水平制表符（ASCII code 9）表示转义形式'\\ T'和\\ t的。不过，我经常打字的字符串作为例如转义制表字符A＆＃x0009; B（没有在杠一TAB A 和 B ），并且至少铛似乎++不要打扰 - 字符串似乎等同于A \\ TB。我喜欢的转义版本更好，因为长期缩进多行字符串在源$ C ​​$ C更好的可读性。

In C and C++ (and several other languages) horizontal tabulators (ASCII code 9) in character and string constants are denoted in escaped form as '\t' and "\t". However, I am regularly typing the unescaped tabulator character in string literals as for example in "A B" (there is a TAB in betreen A and B), and at least clang++ does not seem to bother - the string seems to be equivalent to "A\tB". I like the unescaped version better since long indented multi-line strings are better readable in the source code.

现在，我问自己，这是否是在C和C一般法律++或只是我的编译器的支持。便携性如何在字符和字符串常量转义制表？

Now I am asking myself whether this is generally legal in C and C++ or just supported by my compiler. How portable are unescaped tabulators in character and string constants?

令人惊讶的我找不到答案这个看似简单的问题，无论是与谷歌也没有对计算器（我刚刚发现的这个中隐约相关的问题）。

Surprisingly I could not find an answer to this seemingly simple question, neither with Google nor on stackoverflow (I just found this vaguely related question).

推荐答案

是的，您可以在一个字符串或字符，并至少根据C ++ 11制表符。允许的字符包括（与我的强调）：

Yes, you can include a tab character in a string or character literal, at least according to C++11. The allowed characters include (with my emphasis):

除了在源代码字符集的任何成员
  双引号，反斜线 \\ ，或换行字符

any member of the source character set except the double-quote ", backslash \, or new-line character

（从 C ++ 11标准，附件A.2）

和源字符集包括：

空格字符，控制字符重新presenting 水平标签，垂直制表符，换页，以及新线，加上下面91图形字符

the space character, the control characters representing horizontal tab, vertical tab, form feed, and new-line, plus the following 91 graphical characters

（从 C ++ 11标准款2.3.1）

更新：我刚注意到你问两种不同的语言。对于C99来说，答案同样是肯定的。措辞不同，但基本上是说同样的事情：

UPDATE: I've just noticed that you're asking about two different languages. For C99, the answer is also yes. The wording is different, but basically says the same thing:

在字符常量或字符串，执行字符集的成员应当重新由相应的源代码字符集的成员psented $ P $ 或[...]

In a character constant or string literal, members of the execution character set shall be represented by corresponding members of the source character set or [...]

其中源和执行字符集包括

where both the source and execution character sets include

控制字符重新presenting 水平标签，垂直标签，
  换。

control characters representing horizontal tab, vertical tab, and form feed.

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